Satellite remote sensing of oil spills at sea

Transcription

1 Sateite remote sensing of oi spis at sea Good practice guideines for the appication of sateite remote sensing during oi spi response operations

2 The goba oi and gas industry association for environmenta and socia issues Leve 14, City Tower, 40 Basingha Street, London EC2V 5DE, United Kingdom Teephone: +44 (0) Facsimie: +44 (0) E-mai: Website: Internationa Association of Oi & Gas Producers Registered office Leve 14, City Tower, 40 Basingha Street, London EC2V 5DE, United Kingdom Teephone: +44 (0) Facsimie: +44 (0) E-mai: Website: Brusses office Bouevard du Souverain 165, 4th Foor, B-1160 Brusses, Begium Teephone: +32 (0) Facsimie: +32 (0) E-mai: Houston office Westheimer Road, Suite 1100, Houston, Texas 77042, United States Teephone: +1 (713) E-mai: IOGP Report 549 Date of pubication: 2016 IPIECA-IOGP 2016 A rights reserved. No part of this pubication may be reproduced, stored in a retrieva system, or transmitted in any form or by any means, eectronic, mechanica, photocopying, recording or otherwise, without the prior consent of IPIECA. Cover photographs courtesy of the foowing: (eft) NASA/GSFC, MODIS Rapid Response (pubic domain image via Wikimedia Commons); (centre) MacDonad, Dettwier and Associates Ltd; (right) MacDonad, Dettwier and Associates Ltd/Esri/OSRL. Discaimer Whie every effort has been made to ensure the accuracy of the information contained in this pubication, neither IPIECA, IOGP nor any of their members past, present or future warrants its accuracy or wi, regardess of its or their negigence, assume iabiity for any foreseeabe or unforeseeabe use made of this pubication. Consequenty, such use is at the recipient s own risk on the basis that any use by the recipient constitutes agreement to the terms of this discaimer. The information contained in this pubication does not purport to constitute professiona advice from the various content contributors and neither IPIECA, IOGP nor their members accept any responsibiity whatsoever for the consequences of the use or misuse of such documentation. This document may provide guidance suppementa to the requirements of oca egisation. However, nothing herein is intended to repace, amend, supersede or otherwise depart from such requirements. In the event of any confict or contradiction between the provisions of this document and oca egisation, appicabe aws sha prevai.

3 Sateite remote sensing of oi spis at sea Good practice guideines for the appication of sateite remote sensing during oi spi response operations Cover photographs reproduced courtesy of the foowing: (eft) NASA/GSFC, MODIS Rapid Response (pubic domain image via Wikimedia Commons); (centre) MacDonad, Dettwier and Associates Ltd.; (right) RADARSAT-2 Data and Products MacDonad, Dettwier and Associates Ltd., A Rights Reserved. RADARSAT is an officia mark of the Canadian Space Agency.

4 IPIECA IOGP Preface This pubication is part of the IPIECA-IOGP Good Practice Guide Series which summarizes current views on good practice for a range of oi spi preparedness and response topics. The series aims to hep aign industry practices and activities, inform stakehoders, and serve as a communication too to promote awareness and education. The series updates and repaces the we-estabished IPIECA Oi Spi Report Series pubished between 1990 and It covers topics that are broady appicabe both to exporation and production, as we as shipping and transportation activities. The revisions are being undertaken by the IOGP-IPIECA Oi Spi Response Joint Industry Project (JIP). The JIP was estabished in 2011 to impement earning opportunities in respect of oi spi preparedness and response foowing the Apri 2010 we contro incident in the Guf of Mexico. The origina IPIECA Report Series wi be progressivey withdrawn upon pubication of the various tites in this new Good Practice Guide Series during Note on good practice Good practice in the context of the JIP is a statement of internationay-recognized guideines, practices and procedures that wi enabe the oi and gas industry to deiver acceptabe heath, safety and environmenta performance. Good practice for a particuar subject wi change over time in the ight of advances in technoogy, practica experience and scientific understanding, as we as changes in the poitica and socia environment. 2

5 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Contents Preface 2 About this guide 4 Introduction 5 Oi spi surveiance 6 What is surveiance for oi spis? 6 The roe of surveiance during an oi spi response 6 The toos and approaches used for surveiance 7 during a response Measuring the effectiveness of a 9 surveiance programme Sateite remote sensing as an 10 oi spi surveiance technique The roe of sateite remote sensing as part of an 10 oi spi surveiance programme Meeting the data requirements of a response 10 Using sateite imagery to provide information 13 to the response Estabishing sateite remote sensing 15 within the response Deveoping a sateite imagery pan 16 Preparedness for sateite remote sensing 16 Choosing a sateite imagery provider 18 Creating an oi spi sateite imagery pan 19 Estabishing agreements with sateite 22 imagery providers From sateite remote sensing preparedness 23 to response Stakehoder roes and responsibiities 24 Sateite Remote Sensing (SRS) Coordinator 25 Beyond coordination: estabishing a Sateite 26 Remote Sensing Team Integrating sateite remote sensing into an 27 existing Incident Management System Working with the sateite imagery provider 28 Working with reguatory and governmenta 29 organizations The sateite imagery acquisition workfow 30 The imagery acquisition workfow 30 Imagery acquisition workfow considerations 37 Using and communicating the imagery 40 and data Geo-referencing of sateite imagery 40 Licensing and sharing of imagery 41 Expoitation of the imagery and anciary data 42 in a response Improving imagery provision during and 42 after a spi Storing and archiving imagery 43 Using sateite imagery as evidence for 44 iega discharge Understanding sateite technoogy for 45 oi spi response The basics of sateite technoogy 45 Sateite technoogy for oi spi response 45 Using optica and radar (SAR) sensors for 47 oi spi response Using mutispectra and hyperspectra sensors for 53 oi spi response Innovation in sateite remote sensing technoogy 54 for oi spi response Recommendations for improving sateite 56 remote sensing for oi spi response Critica steps in using sateite remote 57 sensing for oi spi response List of acronyms 58 Gossary of terms 59 References 60 Acknowedgements 61 3

6 IPIECA IOGP About this guide This Good Practice Guide (GPG) buids on two reports, one produced on behaf of the IPIECA-IOGP OSR-JIP entited An Assessment of Surface Surveiance Capabiities for Oi Spi Response using Sateite Remote Sensing (IPIECA-IOGP, 2014a), and the second pubished by the American Petroeum Institute entited Remote Sensing in Support of Oi Spi Response (API, 2013). The API report focuses on how remote sensing is integrated into overa OSR activity (incuding the key individua roes remote sensing may be required to pay), whie the OSR-JIP report concentrates on the surveiance capabiities of sateites (such as the practica issues associated with data avaiabiity). The objective of this Good Practice Guide is to synthesize and summarize the content presented within these reports, and to provide responders, reguators, statutory consutees, industry, nongovernmenta organizations, oi spi response organizations and academia with an overview of the strategic and operationa appication of sateite remote sensing for oi spi response. 4

7 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Introduction To respond to an oi spi effectivey, those invoved in the response operations require accurate and timey information on the ocation, the quantity and characteristics of the oi spied and the characteristics of the areas ikey to be impacted by the spied oi. This information enabes the incident command to effectivey determine the scae and nature of the oi spi scenario, make decisions on where and how to respond, contro various response operations and, over time, confirm whether or not the response is effective. Surveiance is key to providing this situationa awareness during an oi spi response operation. It is supported by a range of different technoogies and techniques, from traditiona and we-tested observation from vesses and aeria patforms to the use of innovative, sma-scae unmanned aeria vehices (UAVs). Sateite remote sensing for oi spi response Sateite remote sensing (SRS) is an additiona surveiance too that can be readiy used to provide synoptic and strategic information to the response. Remote sensing is the acquisition of data about an object or phenomenon without making physica contact with it, often using eectromagnetic radiation. Sateites, and the sensors onboard, can be used as remote sensing patforms to measure properties of the Earth from above the atmosphere and to gather data that can be used for a variety of appications. For oi spi response, sateite imagery provides information that can be used to support various missions, incuding assessing the initia (and potentia future) extent and impact of a spi, panning response operations and monitoring the effectiveness of the response as a whoe. To fufi these roes, sateite remote sensing must meet various requirements of the response, incuding deivering information within certain timeines or at reguar intervas. It must aso be abe to operate in a variety of environmenta conditions, incuding during adverse weather. Operationa guidance: using sateite remote sensing within an oi spi response This GPG provides operationa guidance on how to: prepare a sateite image pan; estabish the roes and responsibiities required during the response; foow and manage the acquisition of sateite imagery; and understand the technoogy (and its imitations) invoved. A basic checkist that shoud be foowed when using sateite remote sensing as part of an oi spi response can be found on page 57, and ists the steps that shoud be foowed prior to, during and after an incident. 5

8 IPIECA IOGP Oi spi surveiance What is surveiance for oi spis? Surveiance is the observation of a spi to gather information that is used to detect, identify, assess and monitor an ongoing spi scenario. Surveiance not ony requires observation but aso the recording, documentation and dissemination of the information gathered so that it can be shared with the necessary stakehoders within the response. During an oi spi response, surveiance can be used for various roes and purposes. In particuar, those organizing the response operations can use surveiance to enhance their situationa awareness of the spi. In addition, the outputs from surveiance incuding imagery and video, maps, spreadsheets and cacuations can be used for panning operations, monitoring and assessing the impact of recovery methods, vaidating and caibrating numerica modes of the spi, and as a communication too for briefing externa parties, such as the media and the pubic. Furthermore, rea-time surveiance can provide tactica support during a response, e.g. by using aircraft to spot oi sicks and direct the dispersant appication vesses to the appropriate area. Exampe of synthetic aperture radar (SAR) C-band microwave image of the Guf of Mexico oi spi in 2010, captured by RADARSAT-2. RADARSAT-2 Data and Products MacDonad, Dettwier and Associates Ltd., A Rights Reserved. RADARSAT is an officia mark of the Canadian Space Agency. Surveiance information that has been recorded and documented can be used post-spi for a variety of other purposes, e.g. providing support for training courses and exercises, and for educationa and academic reference. The information can aso be used to hep address any ega issues and reguatory requirements that have arisen from the spi. In addition to being used during oi spi response operations, surveiance can aso be used as a preparedness measure to monitor areas at potentia risk from oi spis (e.g. areas near instaations, shipping routes, pipeines) on a routine or even a continuous basis. The roe of surveiance during an oi spi response Surveiance is an essentia part of the response tookit, and provides vauabe information on the evoving scenario during a response operation. Oi spi surveiance shoud provide the response team with: an initia detection (or confirmation) and assessment (characterization and quantification) of an oi spi within a specified time frame. ongoing assessment and synoptic monitoring of an oi spi and the response operations at reguar intervas; and tactica support (constant monitoring) for operations and missions at the required time and ocation. The deivery of information within the required time frame is critica for ensuring an adequate eve of situationa awareness, as we as heping with operationa panning and communication. 6

9 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Box 1 What is situationa awareness? Situationa awareness is knowing what is going on around you. For an oi spi response, situationa awareness requires a hoistic yet comprehensive understanding of the spi scenario; this is achieved by identifying, processing and comprehending critica eements of the information provided. Obtaining the right types of information and ensuring that it is correct and up to date is thus intrinsic to gaining an accurate situationa awareness of an oi spi. How does surveiance contribute to situationa awareness? Surveiance is used primariy to detect, characterize and preferaby quantify spied oi that may be present in on-water, in-water and onshore settings. Furthermore, surveiance can be used to gather information on the environment surrounding the oi spi. Surveiance can therefore provide much of the key information needed to inform the response about the evoving spi scenario, such as the ocations of spied oi (absoute and reative), estimates of the quantity of spied oi, characterization of the oi, and even information on the operating conditions (weather forecasts, oca terrain or hydrography, environmenta sensitivities) a of which are of critica importance for situationa awareness. The toos and approaches used for surveiance during a response To ensure that the most appropriate information is provided efficienty during a response, an oi spi surveiance and monitoring programme shoud be put in pace that uses a variety of surveiance approaches and toos to gather the information needed and support the ongoing response (Figure 1). Figure 1 Exampes of surveiance toos that may be used in a response operation 7

10 IPIECA IOGP Surveiance toos can incude: sateites (using optica, infrared and radar techniques); unmanned underwater vehices (UUVs), incuding autonomous underwater vehices (AUVs) (e.g. giders) and remotey operated vehices (ROVs); unmanned surface vesses (USVs), incuding autonomous surface vehices (ASVs) (e.g. AutoNaut, wave giders); surface vesses (using techniques incuding optica and radar, photography and video, and human eye); buoys, trackers and mounted systems (e.g. instruments mounted on rigs or moored independenty); onshore observers (using human eye, photography and video) aeria patforms such as fixed-wing aircraft and heicopters (using techniques incuding human eye, optica and radar surveiance, photography and video); unmanned aeria vehices (UAVs) (using optica and radar techniques); and tethered baoon systems (i.e. aerostats, using optica and infrared techniques). Each too has its advantages and imitations when used to gather information for oi spi response; these characteristics are outined in the API report on remote sensing (API, 2013). For information on surveiance toos other than sateite remote sensing technoogies see IPIECA-IMO-IOGP, 2015 and IPIECA-IOGP, Observing a ocaized sma spi The advantages and imitations of sateite remote sensing technoogies need to be considered in conjunction with the oi spi scenario, as a variety of different factors may affect the overa suitabiity of a particuar too. Factors that may need to be taken into account incude: the size of the spi (and predicted duration); the ocation of the spi (both geographica position and type, e.g. offshore, inand); the environmenta conditions; the operating conditions; the type of oi spit and its behaviour during weathering (e.g. tendency to spread); ogistica issues (e.g. access to depoy the technoogy); reguatory and poitica constraints (incuding contro and reguation of airspace and the ocean, and oca governance of technoogy); the type of response operations; when the information wi be needed; and the ease of integrating and organizing different sources and types of information. For exampe, a ocaized sma spi may ony require human observers; and the depoyment of surveiance aircraft to monitor arger spis coud be prevented by poor weather conditions. In genera, to gather a the information required, a surveiance programme shoud utiize a combination of the surveiance toos that are appropriate for the response. OSRL As an incident progresses, the demands on a surveiance programme wi generay increase, and the programme often divides into strategic (situationa awareness, operations panning and impact monitoring) and tactica (supporting operations) roes. Any too used shoud be capabe of meeting at east one of these roes and their requirements. 8

11 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Measuring the effectiveness of a surveiance programme The overa effectiveness of the surveiance programme wi be most visibe within the response s common operating picture (COP). The COP is a shared view of the incident and its operating conditions, and has been defined as a computing patform based on geographic information system (GIS) technoogy, which provides a singe source of data and information for situationa awareness, coordination, communication and data archiva to support emergency management and response personne and other stakehoders invoved in, or affected by, an incident (IPIECA-IOGP, 2015a). The COP is used to support strategic and tactica decision making within the Incident Management System used to manage the response. The COP aows response personne and other stakehoders to view any data and information generated within the response, incuding surveiance data. Much of the information in the COP is static and can therefore be deveoped and pre-popuated during the response panning phase for the ocation in question. If any surveiance-reevant information required by users is missing from the COP, the surveiance programme wi need to be improved and updated to ensure that a users needs are meet. Detaied guidance on the eements that shoud be incuded in the COP can be found in IPIECA-IOGP, 2015a. Waypoint Mapping/Esri Surveiance data gathered during a response operation is fed into the GIS-based common operating picture to ensure that a stakehoders are operating from a common situationa awareness standpoint. 9

12 IPIECA IOGP Sateite remote sensing as an oi spi surveiance technique Sateites are used as a surveiance too for oi spi response because they can: capture imagery over a arge area in a reativey short time period; capture imagery at varying eves of detai; capture different types of imagery, dependent on the sensor used; be tasked to coect imagery over a certain area on a repeatabe basis; capture imagery in adverse weather conditions (dependent on the sensor onboard); and normay operate independenty of ogistica and poitica constraints. Furthermore, the processing and anaysis of the imagery can be fuy or partiay automated aong with the output of the fina product. Additiona datasets can aso be derived from imagery (such as information on other environmenta conditions or the presence of hazards), whie a fina products can be easiy incorporated into GIS software and dispayed with other types of data. The roe of sateite remote sensing as part of an oi spi surveiance programme SRS can be used to fufi the strategic roes within a surveiance programme during an oi spi response, incuding: supporting the initia detection and assessment; conducting ongoing assessment and synoptic monitoring; and providing pre-spi and baseine data. Each of these roes has its own data requirements. For oi spi response, the deivery of data within a required time frame is often the most critica requirement, as the vaue of sateite imagery data is greaty diminished by deays incurred between its receipt and the production of actionabe inteigence. Tabe 1 on page 11 presents a checkist of the requirements that, as a surveiance too, SRS woud be expected to meet. In the case of ongoing assessment and synoptic monitoring, these requirements may change as the response progresses, i.e. towards the atter stages of ceanup, an image every 2 3 days may be sufficient. The ikeihood of SRS meeting these requirements is determined by various factors that wi vary on a spi-by-spi basis, and wi therefore need to be considered when choosing SRS as a surveiance too. Meeting the data requirements of a response The factors that affect whether SRS can meet the requirements of an oi spi response incude the: set-up and operation of a sateite remote sensing capabiity; data acquisition workfow process; and operating/environmenta conditions. For the initia assessment, the time it takes for data captured by SRS to be transated into information that can be used by the response wi vary from one response to another. 10

13 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Tabe 1 Data requirements for sateite remote sensing Initia detection and assessment Detection of an oi spi Determination of the extent of the reease and other characteristics Providing situationa awareness at the source Supporting the seection of appropriate recovery methods Roes of sateite remote sensing Ongoing assessment and synoptic monitoring Providing updates on the extent, ocation and tracking of the spi Supporting and refining oi spi modeing/forecasting Providing support to operations panning Assessing the impact of response efforts Pre-spi/baseine data Determining spi timeines Identifying fase aarms Estabishing pre-existing geographic setting and the environmenta/ infrastructure condition Identifying resources at risk Providing support for modeing/forecasting Requirements that SRS is expected to meet Data avaiabiity Minimum: data deivery within 24 hours of data request Minimum: data deivery within 24 hours of data request Minimum: data deivery within 48 hours of data request Goa: data acquisition within three hours of data request Goa: meeting a schedued requests. Data coection frequency Minimum: daiy Minimum: daiy Minimum: image from the ast month before the spi Goa: image from the ast 72 hours before spi Coverage Minimum: 100% of spi at required spatia resoution* Goa: additiona imagery of critica or impact areas Minimum: 100% of spi and surrounding area at required spatia resoution* Oi parameters to be assessed Minimum: oi ocation and extent Goa: concentration, thickness**, condition N/A Other parameters to be assessed Goa: identification of any factors that may impede the commencement of operations Goa: post-spi near rea-time conditions (environment, asset ocations, conditions, access, hazard identification) Minimum: pre-spi baseine conditions Goa: anciary datasets identifying resources at risk Critica requirements for an oi spi response Minimum: data format shoud be readabe by GIS software/common operating picture Goa: to provide supporting information, incuding text expanations to hep interpretations * May be provided by mutipe images during the same acquisition. ** See Box 2, Can (sateite) remote sensing determine oi thickness and type? on page

14 IPIECA IOGP To deiver imagery within the first 24 hours of a spi wi require that there are no time deays or ags in the imagery acquisition process, or that the image acquisition has been pre-panned (discussed ater in this GPG). In the absence of pre-panned imagery, it is more ikey that the first imagery wi be avaiabe within the first hours. Sateites may not, therefore, be suitabe for short-ived spis (e.g. ess than 24 hours) or for time-critica missions; for the initia assessment of the spi which shoud be conducted within the first 3 6 hours aeria surveiance is ikey to be the more suitabe too. For ongoing assessment and monitoring, sateites can be programmed to acquire imagery at reguar intervas, and the end products customized to fit the response requirements. As a resut, sateites can generay be highy reiabe in providing repeatabe, routine and/or schedued surveiance, and if there is any potentia disruption to surveiance, this can be reported eary on. This is important when reguar information is required, such as to feed into daiy briefings during operations panning. Sateites cannot, however, provide continuous monitoring; aternative toos, such as tethered baoons, shoud therefore be used if continuous monitoring is required for operations such as directing response vesses towards the oi. The capabiity to provide historica surveiance is aso a key advantage of using SRS as a surveiance too. Sateite archive imagery can aso be used to provide pre-spi imagery of the area, which can hep to identify when the spi occurred and show the characteristics and conditions of the surrounding environment. This is, however, dependent on a suitabe image being present within the archive cataogue for the affected area, and cannot necessariy be guaranteed. In genera, sateites can operate independenty of adverse weather conditions and operationa constraints that may hinder other toos. For exampe, if the right sensor-sateite combination is used, sateites can acquire imagery in adverse weather conditions (e.g. coud cover, rain). Other toos may be restricted by operationa contros, such as the reguation of working hours for aircrews used in aeria surveiance. Furthermore, sateites are subject to fewer poitica constraints (e.g. ground or airspace contros) compared to other toos; however, if an area is subject to miitary restrictions, the use of sateite surveiance may not be possibe. It is aso possibe that ega or reguatory provisions may impose restrictions on the use and sharing of certain surveiance data and information in some geographic ocations. Sateites shoud be used in conjunction with other surveiance toos to ensure that a of the response s data requirements are met. Cedre Overa, sateites can provide a reiabe and repeatabe source of surveiance information to the response, but shoud be used in combination with other surveiance toos to ensure that a of the response s data requirements can be met. 12

15 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Using sateite imagery to provide information to the response The purpose of any surveiance too is to provide information that can be used by end users to improve decision making within the response. The end users of sateite imagery may incude: response staff (those in charge/command, those organizing genera and specific operations and those in the fied); the party responsibe for the spi; reguatory or governmenta organizations; the media; and the genera pubic. The information provided may be essentia to informing situationa awareness at the command eve, or for providing operation-specific inteigence, e.g. the ocation of individua sicks when panning in-situ burning operations. Tabe 2 outines the types of information that SRS can provide to the response through image processing and interpretation (by both human and computer anaysis). Whie this information can be provided by other surveiance toos, the imagery produced by sateites has various advantages over its counterparts that may make it a preferabe option. Tabe 2 Information provided by sateite remote sensing Aspects of the spi/ response to be assessed Presence of oi on water Information provided by SRS Detection of oi on water Rejection of fase aarms Vaidation of oi on water (using expert interpretation) Oi spi measurements and characteristics Location of the oi spi/surrounding area Geographica ocation of the oi spi and individua sicks/monitoring sick movement Extent of the oi spi Number of sicks Quantity of oi spied (estimate)* Type and condition of oi spied (if possibe, wi require expert interpretation)* Physica ocation (on-water, onshore, inand) Associated environmenta conditions (ocean currents, surface type, ice coverage) Environmenta sensitivities in the area (mangroves, nesting areas) Operating conditions Socio-economic factors Ongoing operations Associated physica characteristics that coud impede operations Access routes Areas of habitation/urbanization nearby Economic vunerabiities (fishing zones, farmand) Location of resources and assets and number depoyed * See Box 2, Can (sateite) remote sensing determine oi thickness and type? on page

16 IPIECA IOGP Box 2 Can (sateite) remote sensing determine oi thickness and type? The determination of oi spi thickness and type through the anaysis of imagery is a prominent area of research in both the oi spi and remote sensing industries. Whether a remote sensor is depoyed on a vesse, aircraft or sateite, it needs to be capabe of distinguishing between different oi thicknesses across a spi to cacuate spi voumes as we as improve the abiity to pan ahead and determine the most appropriate recovery techniques. Using image anaysis to determine oi thickness and type requires the optimum combination of sensors, specific operating conditions and expert interpretation. Research is sti being carried out on this technique, athough some progress has been made in determining thickness using hyperspectra imagery. These advances are discussed further in the chapter on Understanding sateite technoogy for oi spi response on page 45. The main advantages of using sateite imagery incude: automation of the processing and anaysis of data as soon as it is downoaded, e.g. to automaticay detect oi spis and determine their extent (athough this woud normay be vaidated manuay); the abiity to fuse (integrate) severa ayers of data to hep with data vaidation, e.g. using different types of data to hep in the detection of fase aarms; the abiity to derive anciary datasets that can inform other parts of the response (e.g., deriving oi movement, wind and current directions can hep to vaidate and refine oi spi trajectory modeing); the abiity to mosaic (i.e. stitch together) imagery with reative ease, creating arge-coverage imagery usefu for base maps and operation panning; consistency of the format of the imagery and its outputs, enabing fina products to be standardized across responses; additiona datasets reating to other environmenta conditions and hazards can be derived from the captured imagery; and fina products can be easiy incorporated into GIS software and dispayed with other types of data. The data outputs from other surveiance toos are unikey to provide a of these advantages. For exampe, whie a highy inteigent camera system onboard an aircraft may be abe to automate data processing and fusion, it is unikey to match the coverage or eve of detai that sateites are abe to provide. In addition, data captured by the different technoogies used during aeria surveiance ranging from inteigent camera systems mounted onboard to hand-hed cameras operated by human observers viewing the scene through an aircraft window can be variabe and may resut in inconsistencies in the output format. 14

17 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Estabishing sateite remote sensing within the response Recent advances in airborne remote sensing, and in UAV technoogy in particuar, might ead some to beieve that SRS no onger has a pace in spi response. However, SRS remains a unique contributor to wide-area, synoptic views required by the COP. By combining the abiity to schedue and programme sateites as we as automate the processing, anaysis and deivery of the imagery, SRS can prove itsef to be a robust and reiabe way of acquiring and providing surveiance information throughout the response. Fundamentay, once the initia sateite imagery has been acquired, a pan can be impemented for future acquisitions. This wi enabe the response team to know the times and the frequency at which they wi receive sateite imagery, as we as the area covered and the type of imagery received (athough the quaity or usefuness of the data captured wi be subject to the appropriate weather conditions). This is of particuar use for ongoing assessment and synoptic monitoring as we as operations panning, where the provision of consistent, reguar and punctua information is critica to aiding the response. The key chaenge when estabishing SRS within a response is the initia process of identifying and seecting the most appropriate sateite system and sateite imagery provider to use. It is essentia that the personne responsibe for these decisions have appropriate authority and experience, otherwise the process can easiy become drawn out or over-compicated. The onger it takes to choose the required technoogy, the onger it wi be before data acquisition can begin; this wi therefore be an important constraining factor in determining whether SRS can meet the reevant data requirements for the initia time-critica mission of assessing the oi spi. This difficuty can be overcome by making the reevant preparations, preferaby as part of the contingency panning process, in advance of a spi occurring. As the capabiity and coverage of a sateite is fixed, the most appropriate sateite system (and sateite imagery provider) can be preidentified for a particuar area, and even the expected timings, the revisit frequencies and spatia coverage can be determined to create a preiminary sateite imagery pan. The sateite imagery pan is an important preparedness measure that shoud be expoited within a response. MacDonad, Dettwier and Associates Ltd. Seecting the most appropriate sateite can be one of the most crucia chaenges for the response organization. The exampe on the eft is RADARSAT-2, an advanced commercia radar sateite operated by MacDonad, Dettwier and Associates Ltd. 15

18 IPIECA IOGP Deveoping a sateite imagery pan To faciitate the efficient use of SRS as a surveiance too during a response, it is recommended that the necessary groundwork is conducted as an oi spi preparedness measure, preferaby as part of the oi spi contingency panning process (see Box 4 on page 17). This panning work shoud resut in the formuation of a sateite imagery pan that contains the information necessary to commence SRS operations with the minimum deay in the event of an oi spi incident. The deveopment of a sateite imagery pan invoves: identifying one or more sateite imagery provider(s); choosing the most appropriate technoogy for potentia spi scenarios in the area of interest (AOI); deveoping a standard operating procedure for requesting the sateite imagery from the provider; and compiing the above information in a readiy accessibe format. Once the sateite imagery pan has been finaized, it can be incuded as part of the oi spi contingency pan (OSCP) or incident response pan. The creation of an effective sateite imagery pan is described in more detai beow. Sateite coverage map of the North Sea by RADARSAT-2, iustrating a SAR owincidence ange imaging mode over a nine-day period. MacDonad, Dettwier and Associates Ltd. Preparedness for sateite remote sensing The sateite imagery pan aims to increase the ikeihood that the imagery is acquired successfuy and used effectivey in a response. The creation of a sateite imagery pan shoud foow a process simiar to that of an OSCP; existing sateites and associated sateite imagery providers shoud first be compared to assess their reative capabiities and provision over the AOI for various scenarios, in particuar accounting for seasona weather conditions. The most appropriate choice of sateite technoogy and imagery provider is then made, and the detais are documented within the pan. The pan shoud aso describe the operating protocos and procedures that wi be foowed in the case of a spi, incuding how to order imagery from a sateite imagery provider, and the expected data requirements of the response. 16

19 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA The deveopment of a rigorous sateite imagery pan requires those responsibe for creating it to have: experience in understanding and using sateite remote sensing technoogy; an understanding of the expected data requirements of a potentia response; knowedge of the various response scenarios that coud occur over the AOI; and access to sateite image panning software that can aid in identifying the appropriate sateites (see Box 3). Box 3 Sateite image panning software Commercia sateite image panning software is avaiabe, either as desktop packages or as web-enabed services. These can be used to optimize the assessment and monitoring of areas of interest, through trade-offs invoving tempora and spatia samping, cost and type of imaging sensors. One exampe is SaVoir, a mutisateite swath panner provided by Taitus Software. SaVoir was originay deveoped for the European Space Agency to support operations of the Internationa Charter for Space and Major Disasters. The aim was to provide an easy-to-use too to quicky identify potentia data acquisition opportunities over any area of interest and with any sateite and sensor combination, speeding the efforts in data ordering for disaster reief. Whie these capabiities may be avaiabe in-house for use by the party who is creating the pan (whether a company, response organization or government/reguatory agency), it is recommended that a sateite imagery pan be deveoped in conjunction with a sateite imagery provider. As the sateite imagery provider wi be responsibe for acquiring the imagery, they wi need to be aware of the potentia scenarios they may become invoved in. They wi pay a major roe in ensuring that the sateites chosen are avaiabe and suitabe for use, and that the imagery requested is suitabe for the response. Furthermore, as the sateite imagery provider wi have access to their own sateite panning software, they wi be abe to provide further detais regarding the samping capabiities, incuding the projected sateite path, revisit capabiities and spatia coverage, as we as a potentia imagery deivery schedue for the various sateites. Box 4 Oi spi preparedness and contingency panning Oi spi preparedness is part of a framework that seeks to improve industry s capabiity to respond to oi spis. The oi spi preparedness and response framework is founded on the beief that a successfu response depends on we-trained personne working to a we-deveoped response strategy that is adequatey resourced and propery exercised and tested. The preparedness process consists of: identifying potentia events; panning scenarios based on previous events that encompass the fu range of potentia impact and response chaenges; deveoping response strategies based on these scenarios; and providing the response resources that are ikey to be required. The oi spi preparedness process is fundamenta to contingency panning and the deveopment of an OSCP. An OSCP is a document, or suite of documents, that provides guidance on how to respond to an oi spi, providing the instructions and information needed in a response and demonstrating that a rigorous panning process has been undertaken in buiding response capabiity for the region or faciity at risk. The desired outcomes of both processes are to: ensure that pre-approved response strategies are in pace to respond to a spi as rapidy and effectivey as possibe; hep to overcome barriers during a response through rapid non-partisan decision making and the sharing of objective information; and everage the right expertise before, during and after a spi through cear predefined roes and responsibiities, resuting in the designation of operationa authority ony to appropriate response parties. A of the above increases the ikeihood of a successfu and effective response operation. More information about the contingency panning process can be found in the IPIECA-IOGP Good Practice Guide on contingency panning for oi spis on water (IPIECA-IOGP, 2014b). 17

20 IPIECA IOGP By invoving the sateite imagery provider at an eary stage, the party can benefit from any expertise and experience that the provider may have in using sateite remote sensing for oi spi response; this can hep to further ensure that a robust pan is deveoped. In addition, invoving the sateite imagery provider eary on aows for a good working reationship to be estabished without the pressures of responding to an incident; this is ikey to make it easier to work together in the future if an incident occurs. Estabishing a good reationship with the imagery provider may aso present additiona tangibe benefits for exampe, the provider may have their own image panning tempate or other standardized protocos and procedures in pace that can be adapted for the response, thereby reducing the amount of work that needs to be carried out in deveoping the pan. Choosing a sateite imagery provider When seecting a sateite imagery provider, it is recommended that a Request for information is first prepared and sent to interested providers asking them to outine their capabiity for the provision of sateite imagery and coverage over the AOI. Different sateite imagery providers have access to different sateites, and the capabiity of each sateite is ikey to vary depending on the types of sensors used and on the tempora and spatia coverage across geographica regions. It is therefore important to identify who can provide the optima soution for the AOI. Once the most suitabe sateite imagery provider(s) is identified, the sateite imagery pan can be deveoped with the provider s input as required. Eary engagement with sateite operators (and remote sensing speciaists) is key to ensuring that SRS operations can be impemented efficienty at the time of an oi spi response. Access to mutipe sateites It is vita to ensure that the sateite imagery provider chosen has access to mutipe sateites (and/or sateite operators); this wi ensure that sateite imagery can be acquired as quicky as possibe during a response. At any one point in a day, the avaiabiity of sateite imagery over a particuar AOI can be imited. This is due to factors such as: weather conditions that may prevent the capture of usabe imagery; sateites not being avaiabe for tasking due to maintenance issues; or that the AOI is poory samped by sateites at the particuar time of day due to orbit configurations. These factors are discussed ater in this guide. As a resut, choosing a sateite imagery provider that has access to more than one sateite wi increase the ikeihood of a sateite being successfuy tasked, and of usabe imagery being captured within the required time frames. Box 5 Sateite imagery provider or sateite operator or both? Sateite imagery providers act as a middeman, taking orders from customers and sending these requests on to sateite operators (who are responsibe for tasking and maintaining the sateite). Often, the imagery provider and sateite operator wi be the same company. In other scenarios, sateite imagery providers wi have distributor agreements, aowing them to submit orders to the sateite operators for task requests and then provide the imagery to the cient on behaf of the operator. 18

21 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA In the case of a significant incident, it is ikey that the response wi require access to a commercia sateites avaiabe to maximize the probabiity of success and protect against gaps in data due to tasking conficts, transmission faiures, etc. Why wi the sateite need tasking? Sateites are generay used for coecting data prospectivey and buiding up a ibrary of imagery that can be referenced at any time. However, a pre-existing image ibrary wi not aways be sufficient to satisfy a customer s specific requirements. For this reason, sateite operators offer various tasking options to externa parties. Tasking enabes end users to order specific data from a particuar pass of the sateite over the AOI, thereby providing end users with near rea-time data. In practice, a combination of both approaches may be used. However, the majority of sateites suitabe for oi spi response wi operate as tasked sateites and wi often have been tasked months in advance to compete acquisitions for particuar purposes. As a resut, to acquire sateite imagery for an emergency response, an order wi need to be submitted to the sateite operator that asks for the sateite to be tasked to acquire imagery over a certain AOI when it passes over on its next orbit. It is important to bear in mind that urgent tasking requests may need to take precedence over existing, potentiay ong-standing orders for data from the same sateite, and that the specific tasks requested by the response team wi need to be carried out as soon as possibe. For these reasons, a tasking order wi need to be submitted as a high priority request, and is therefore ikey to incur additiona associated costs. Creating an oi spi sateite imagery pan In genera, a sateite imagery pan shoud provide: 1. Contacts for ordering sateite imagery: this shoud incude the contact detais of sateite imagery provider(s), as we as detais of any existing agreements with those providers. 2. A standard operating protoco (SOP) for ordering imagery: cear instructions shoud be provided for ordering imagery, together with a description of the data specifications of the imagery and the expected fina product. See beow for addition information on the SOP. 3. Potentia acquisition pans for various timescaes: this shoud incude exampe approaches to scheduing reguar imagery acquisitions for various timescaes. 4. List of suitabe sateites for varying scenarios: an initia evauation of sateites suitabe for use for a range of scenarios, missions and operating/environmenta conditions shoud be documented; the evauation shoud incude the sateite data capabiities (e.g. revisit frequency) and the expected tempora and spatia coverage over the AOI. 5. Reguatory requirements for the use of sateite remote sensing within the AOI: detais of the reguatory requirements pertaining to the required imagery, frequency and deivery times or required coverage of the spi, shoud be ceary documented. 6. Licensing and/or terms of use for the imagery: the pan shoud incude an outine of how the imagery can be used and shared within the response, together with any conditions governing its use, e.g. acknowedgement of the sateite imagery suppier/sateite provider. 19

22 IPIECA IOGP Standard operating protoco The specifications provided within the SOP incude the data specifications (such as preference of imagery type and expectations for deivery times), fina product specifications (such as the output format, expected detais provided, map tempates) and genera organizationa specifications (such as contact detais, data sharing procedures) that woud be required by the response. These specifications are used to pre-pan imagery and can be referred to during a response to hep communicate exacty what is expected from the sateite imagery provider. Having these specifications to hand minimizes the time spent on ascertaining the response requirements, and aso reduces the risk of ambiguity for both the response team and sateite imagery provider regarding what wi be provided. The specifications to be incuded within the SOP are outined in Tabe 3 on page 21, which provides a minimum recommendation of the detai that shoud be pre-panned and ready to give to a sateite imagery provider, as we as preferred and optiona detais that can aso be incuded within the sateite imagery pan. Image pre-panning may aso incorporate a potentia acquisition pan. This woud detai how to set up reguar acquisition requests for varying periods of time, and shoud incude information on when, and how often, imagery shoud be acquired, and whether this is ikey to change as the response progresses or for certain missions. As this information is ikey to be incident-specific, it can ony serve as genera guidance and shoud be updated, based on the spi scenario, before impementation during an oi spi response. Reguatory requirements The sateite imagery pan shoud acknowedge whether any reguatory requirements for using sateite imagery within a response exist for the AOI. For exampe, the pan shoud stipuate whether the use of sateite remote sensing is mandatory, and if so, what requirements it shoud be abe to meet (e.g. capacity to operate during the night). The use of sateite remote sensing as part of an oi spi response operation is a reativey new technique, and its reguation is not yet standardized. It is therefore recommended that advice be sought directy from the reguators during the deveopment of the sateite imagery pan. In addition, the icensing and/or terms of use shoud be agreed at the outset to ensure that the response operators are abe to use the imagery according to their needs during a response. Using and updating the sateite imagery pan Once competed, the sateite imagery pan can be incuded within the OSCP as a supporting document. It can aso be integrated with other fied deveopment and emergency response pans as necessary. As with the OSCP, the sateite imagery pan shoud be updated as and when the situation changes, for exampe when new sateites are aunched or existing sateites retired from service, or when a new agreement is reached with a sateite imagery provider. As a minimum, the pan shoud be reviewed every 6 12 months. 20

23 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Tabe 3 Data specifications to be incuded in the standard operating protoco Specification Minimum Preferred Additiona The required AOI with the respective coordinates Coordinates avaiabe to hand (i.e. in note form) with ongitude and atitudes. The coordinates shoud be provided in an acceptabe coordinate reference system (CRS). Coordinates shoud be provided in a format that can be interpreted by any GIS or image processing software, e.g. using a KML fie or providing a CSV fie with ongitude and atitudes. This shoud hep prevent errors occurring when transmitting the coordinates of the AOI (e.g. transcribing coordinates over the teephone may resut in atitudes and ongitudes being inadvertenty transposed or misinterpreted). For arger areas, areas of differing priorities or mutipe AOIs, a geodatabase consisting of vector fies for each AOI, pus information about each AOI within the attribute tabe (e.g. imagery requirements) shoud be avaiabe. Operationa Required deivery time Expectation of when the imagery is required/within a certain time frame. Daiy pan of when imagery wi be needed for the first few days of the response. Request for genera timings of image acquisition and deivery times. Imagery requirements Oi parameters that shoud be assessed Coverage of oi spi required. Leve of detai required. Extent of oi spi and individua sicks. Estimated area covered by the spi. Coverage of oi spi required. Type of imagery pre-identified. Spatia resoution identified. Extent of oi spi and individua sicks. Estimated area covered by the spi. Oi characterization. Data-specific Fina output requirements Description of expected fina product, e.g. PDF map, data fies. Specification of fina product eve/eve of processing required. Anaysis of the types of oi spis to be provided. List of anciary data sets to be provided. Types of products to be extracted from imagery. Map tempate (supporting information) List of expected features to be present on a map and/or with data sets. Standard tempate provided for PDF maps, containing a detais required from imagery (e.g. surface area estimations). Output Standard tempate estabished for providing data products, incuding origina raster imagery and/or vector fies of the digitized spis. Contact detais of those requesting imagery Data sharing procedures Contact of preferred sateite imagery provider to be used. Detais of an emai address or fie-sharing site for fina products to be sent. Direct contact detais of a key individua within the preferred sateite imagery provider. Detais of the agreement with the preferred sateite imagery provider. Open Geospatia Consortium (OGC)-compiant data formats provided. Access given to upoad directy to the COP. Organization Basic data format provided. 21

24 IPIECA IOGP Estabishing agreements with sateite imagery providers During the creation of a sateite imagery pan, it may be beneficia to estabish an agreement with the seected sateite imagery provider(s) that outines the intent for both parties working together in the event of an oi spi response. The agreement may be informa or formaized through a Service Leve Agreement (SLA). An SLA wi provide a contractua obigation, stating the eve of service expected by both parties; for exampe, the sateite imagery provider may agree to offer an emergency response on-ca service 24 hours a day for 7 days a week. Whether formaized or not, the agreement shoud outine specific operationa detais regarding the authorization and impementation of the sateite imagery pan. For exampe, this may incude a requirement for the response personne to suppy the imagery provider with an authorized request form before sateite tasking can begin, or a requirement for any potentia costs to be Box 6 Oi spi detection and monitoring programmes As previousy mentioned, surveiance can be used to monitor areas at risk from oi spis (e.g. near instaations, shipping routes, pipeines) on a routine or even continuous basis as a preparedness measure. Many different techniques can be used to monitor these areas for oi spis, from fying UAVs aong pipeines to identify eakages, to using heicopters to survey rigs. Sateites can be used proactivey on a routine basis to monitor areas at risk, providing an initia aert that a possibe oi spi has been detected. Furthermore, sateites can cover arge areas at risk, unike mounted radar system on rigs and instaations. As a resut, sateites can be used for monitoring on a variety of scaes, and are therefore appropriate for use in regiona and goba initiatives, as we as for meeting individua ocaized needs. As a separate preparedness measure, sateite imagery providers are aso abe to provide oi spi detection programmes for individua customers, incuding customized programmes to monitor priority areas or during specific time periods. Severa oi spi detection/monitoring programmes are currenty in pace to monitor specific areas by using sateites. An exampe is the European Maritime Safety Agency s CeanSeaNet programme, which monitors waters cose to European shores and provides an aert and the reevant imagery to member states when a possibe oi spi is detected. The service suppies radar and optica sateite imagery to 28 participating states, incuding EU Member States and their overseas territories. EMSA, 2011: CeanSeaNet First Generation, p8. Exampe of a focus map generated from data captured by the European Maritime Safety Agency s (EMSA s) CeanSeaNet programme (16 Apri January 2011), which covers a European sea areas. 22

25 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA ceary communicated. An agreement can aso be usefu to hep carify and confirm the potentia icensing and/or terms of use of the imagery between the party and sateite imagery provider (see aso the section on Using and communicating the imagery and data on page 40). The type of agreement with the imagery provider can range from a response-ony arrangement to a fuy comprehensive preparedness service. For exampe, an SLA may be put in pace that offers many benefits other than reactive imagery acquisition, such as oi spi detection monitoring, the provision of sateite imagery updates to rue out fase positives (see the ist of potentia fase aarms in Tabe 14 on page 48), and the provision of archive imagery that can be used for baseine monitoring and as evidence for use in cases of iega discharge (i.e. third parties dumping oi near oi instaations). In addition, the sateite imagery provider coud provide access to a rea-time assessment of potentia image acquisition opportunities as part of the sateite imagery pan, so that the pan can be updated and executed without deay in an event of a spi. From sateite remote sensing preparedness to response The creation of a sateite imagery pan requires a person within the response party to take responsibiity for its deveopment and impementation; for arge companies and organizations with sufficient capacity, this may be the task of a dedicated sateite remote sensing or technica speciaist working on a particuar preparedness project or assigned with genera responsibiity for the sateite remote sensing team. It may aso be the case that the deveopment of the sateite imagery pan is outsourced to an oi spi response organization, a technica consutancy or the sateite imagery provider. Whenever the pan deveopment is outsourced, an individua within the response party wi sti need to take ownership of the sateite imagery pan, even if this roe ony invoves documentation and management (version updates) of the pan, and its distribution to stakehoders in the case of a spi. For companies and organizations that do not have a sateite imagery pan in pace for existing operations, it is recommended that an appropriate pan is deveoped; this task coud be assigned to the same individua responsibe for ongoing reviews and improvements in the preparedness and SRS capabiity of the company as a whoe. As soon as a spi is reported, the process of obtaining sateite imagery for the response can be put into action using the sateite imagery pan. Impementing the pan requires that one or more individuas within the response team have at east some basic knowedge and experience of working with sateite remote sensing. These individua(s) wi be responsibe for initiaizing and communicating the pan, and iaising with those in charge of organizing the response (the Incident Command) and with the sateite imagery provider. The responsibe person(s) wi aso need to hep update the existing data requirements to refect the evoving scenario, incuding reviewing sateite options and their suitabiity for operation in changing weather conditions. If SRS preparedness measures have not been taken and a sateite imagery pan does not exist, the responsibe person(s) wi aso need to take on the responsibiity of deveoping a pan eary on in the response effort. The different roes and responsibiities for the use of SRS shoud be carified at the start of a response, and can be incuded in the sateite imagery pan, if appropriate. 23

26 IPIECA IOGP Stakehoder roes and responsibiities The use of sateite remote sensing within a response invoves severa stakehoders, who have varying roes and responsibiities to ensure that the sateite imagery pan can be impemented without deay and the resuting imagery can be used effectivey within the response. The stakehoders and their roes are summarized beow in Tabe 4. An individua within the response team (whether this is the responsibe party (RP), the oi spi response organization (OSRO) or other managing organization such as a oca government agency) is required to take on the roe of Coordinator at the start of a response. The Coordinator shoud be responsibe for impementing the sateite imagery pan and iaising between the reevant stakehoders during the response. Preferaby, an SRS Coordinator shoud be identified by companies, OSROs and oca government agencies during the contingency panning process, and shoud be responsibe for deveoping, updating and impementing the sateite imagery pan. Tabe 4 The roes and responsibiities of stakehoders when using sateite remote sensing for oi spi response Stakehoder The responsibe party (RP) Roe The party responsibe for the spi, which in some cases wi authorize the use of SRS. This party may aso be responsibe for managing the spi response and using the imagery directy. Responsibiities Provide the sateite imagery pan (if it exists). Authorize the expenditure and use of sateite imagery. Provide a Coordinator/Liaison responsibe for managing SRS within the response. The oi spi response organization (OSRO) The organization coordinating and managing the response (if not conducted internay by the RP), and that wi use the sateite imagery. Provide the sateite imagery pan (if it exists). Provide a Coordinator/Liaison responsibe for managing SRS within the response (if required). The sateite imagery provider The organization providing the imagery to the response. The provider may be pre-identified within a sateite imagery pan or chosen during the response. Deveop a sateite imagery pan if one does not exist. Provide sateite imagery according to the requirements outined by the pan and ensure that it is appropriate for the response. Ensure that the response personne understand the acquisition timings and the resuting imagery provided. Reguatory or governmenta organizations (e.g. oca government agency) Organizations that may enforce any ega or reguatory requirements for the use of sateite imagery. They may aso use the imagery for their own purposes, or even be responsibe for managing the response. Inform stakehoders of any reguatory or ega requirements. 24

27 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Sateite Remote Sensing (SRS) Coordinator The initia task of the SRS Coordinator is to determine whether a sateite imagery pan exists for the spi area; the pan may be hed by the RP or, if mobiized, the OSRO, or a oca government agency. If a pan is not in pace, the SRS Coordinator shoud take the necessary steps to deveop a pan by: iaising with those organizing the response (i.e. the Incident Command which usuay consists of representatives from both the RP and the OSRO, as we as other key stakehoders such as maritime agencies and coast guards) to ascertain their needs and requirements; identifying a suitabe imagery provider; and deveoping a sateite imagery pan with the hep of the imagery provider. Any existing pan wi aso need to be updated to refect the operating environmenta conditions. Once a pan is in pace, the image acquisition process can begin. Based on the response requirements and environmenta conditions, the sateite imagery provider wi determine the most appropriate technoogy to use for the scenario and, if required, wi present potentia options to the SRS Coordinator. The sateite imagery provider wi then manage the acquisition process (from tasking to fina product deivery) based on the specifications given by the SRS Coordinator; these wi incude the timescaes, output format and any anciary data requested. The SRS Coordinator shoud communicate these specifications and timescaes to Incident Command and, once the fina imagery products are received, manage and disseminate them within the response. The responsibiities of the SRS Coordinator fa into the foowing five categories: 1. Awareness and understanding of any pre-existing sateite imagery pans for the area at risk. 2. Ordering imagery by iaising between sateite imagery providers and incident command (incuding chain-of-custody oversight). 3. Basic data management, and quaity assurance and contro of fina products (incuding origina data and imagery). 4. Basic interpretation of fina products (e.g. understanding what the imagery depicts). 5. Sharing, stewardship, discosure and dissemination of information and data. To fufi these tasks, the SRS Coordinator wi need to have reevant knowedge, experience and organizationa skis, incuding as a minimum: an understanding of the basic principes of remote sensing; a basic understanding of the different technoogies avaiabe (incuding sensors and patforms); the abiity to discuss and expain the reative advantages/imitations of the different technoogies to stakehoders; the abiity to expain the image acquisition workfow to stakehoders; experience in ordering imagery from sateite imagery providers; experience in using the fina products offered by sateite imagery providers; the abiity to project manage the acquisition process, incuding good communication and organizationa skis; and the abiity to manage (store and archive) the products deivered. 25

28 IPIECA IOGP Meeting these requirements wi hep to ensure that the needs of the response are communicated accuratey and efficienty between the incident command and the sateite imagery provider, and that the data is distributed among the appropriate personne within the response as soon as it has been deivered. Beyond coordination: estabishing a Sateite Remote Sensing Team In addition to iaising between stakehoders, and ordering and managing the sateite imagery, various other tasks wi need to be competed so that the fina products are ready to be used by the response. These tasks may incude: imagery panning (forming initia orders and panning future tasking requests); data/image processing (incuding independent processing of imagery products received from the imagery providers); data generation; data vaidation and quaity assurance; advanced data management, using databases and/or cataogues to hep end users ocate the required imagery; and integrating imagery into GIS software and/or the Common Operating Picture (or providing data in a GIS-compatibe format). The sateite imagery provider conducts the majority of these tasks in the first instance, in particuar image panning, processing and data vaidation. However, if the response team has the capacity, both in terms of time and resources (manpower, computing), and the capabiity to carry out these tasks independenty, a technica SRS Team can be estabished. The exact set-up of an SRS team wi vary according to the nature of the response. For exampe, these responsibiities may rest with ony one individua taking on the roe of both SRS Coordinator and SRS Anayst; or a team may be estabished which incudes severa speciaists, each with their own designated roes. In genera, the various set-ups that may be estabished are: a singe individua within the response, acting as both SRS Coordinator and SRS Anayst; a team of speciaists within the response, incuding an SRS Coordinator and separate a SRS Anayst; and an individua or sma team of speciaists within the response, incuding an SRS Coordinator, which aso uses the sateite imagery provider to provide extra capacity when necessary. However the team is structured, it is essentia that they have appropriate experience and knowedge to compete a of the required tasks. 26

29 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Integrating sateite remote sensing into an existing Incident Management System An Incident Management System (IMS), such as the Incident Command System (ICS) used within the USA, is the fundamenta command and contro organizationa structure of an emergency response team. For any response, a form of IMS wi be in pace that defines the roes and responsibiities of those invoved in the response, as we as the units they beong to and the reporting structure within. Figure 2 iustrates the basic IMS structure. For more information on the IMS see the IPIECA-IOGP Good Practice Guide entited Incident management system for the oi and gas industry (IPIECA-IOGP, 2014c). Figure 2 The organizationa structure of an Incident Management System To integrate SRS into the response s IMS, it is recommended that the SRS Coordinator (and/or SRS Team) is assigned to the Panning Section and reports to the Situation Unit Leader. A centra function of the Panning Section invoves the coection and evauation of operationa information about the incident, incuding the current and forecasted situations (e.g. weather, oi spi trajectory, air quaity, ecoogica and socio-economic features at risk) and the status of assigned resources. The Situation Unit wi coect and evauate situation information for the response (incuding information on actions currenty being taken and forecasts of future incident management activities and information); the Documentation Unit wi then manage the overa documentation for the response and deveop an overa administrative record, incuding ogs, fies, pans, maps and other records for the response. In addition, the Panning Section wi be responsibe for estabishing and maintaining the COP. The SRS Coordinator shoud provide data and information to the Situation Unit so that they can be integrated into the overa information management process. The SRS Coordinator shoud aso be aware of whether a GIS team is present within the response, and if so, shoud work with them to popuate the COP with sateite imagery and data, ensuring that any protocos and procedures (such as naming conventions, data formats etc.) are consistent across the response. It is possibe that the individua acting as SRS Coordinator may aso be invoved in other response teams. 27

30 IPIECA IOGP Coordination with the Air Operations Team The SRS Coordinator shoud aso work cosey with the Air Operations Team, which is responsibe and accountabe for the safe operation and tracking of aircraft, and typicay operates out of the Operations Section. The Air Operations Team can use sateite imagery to identify areas affected by the spi, and to hep guide surveiance/dispersant-spraying aircraft to their targets. The imagery can aso be used to monitor the impact of aeria dispersant appication. Near right: map showing sateite surveiance data being used to guide aeria surveiance. The (bue) poygons show the outine of the oi detected by sateite (shape fies in a map dispay), whie two separate aeria surveiance overfights are iustrated in red and green, respectivey. RADARSAT-2 Data and Products MacDonad, Dettwier and Associates Ltd., A Rights Reserved. RADARSAT is an officia mark of the Canadian Space Agency. MacDonad, Dettwier and Associates Ltd. OSRL Far right: conducting aeria surveiance. To ensure that the Air Operations Team is using the most up-to-date information, the SRS Coordinator shoud inform the Team of the expected acquisition and deivery times of the sateite imagery. This wi enabe the Air Operations Team to schedue their operations to take pace as soon as the imagery is avaiabe for panning. The SRS Coordinator shoud ensure that the Air Operations Team is abe to access the imagery as soon as it is accessibe. The IPIECA-IMO-IOGP Good Practice Guide entited Aeria observation of oi spis at sea provides guidance on the strategic and operationa use of aeria patforms for oi spi response (IPIECA-IMO-IOGP, 2015). Working with the sateite imagery provider As we as providing the imagery, the sateite imagery provider pays a major roe in ensuring that the imagery ordered is appropriate for the response and that the fina products are suitabe for use by the end users. This is particuary important when: ony an SRS Coordinator with imited SRS experience is present within the response team; a sateite imagery pan has not previousy been deveoped; or the in-house SRS team does not have the capacity to fufi a of the SRS tasks required. Estabishing a good working reationship with the sateite imagery provider is important and can be achieved by putting in pace an agreement that outines the requirements of the response. 28

31 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA The SRS Coordinator shoud be aware of any agreements that exist with a sateite imagery provider, whether as part of the sateite imagery pan or as an informa arrangement between parties. Parties to the agreement with the imagery provider may be the responsibe party, an oi spi response organization, or both. For exampe: The responsibe party may have a pre-existing agreement with a sateite imagery provider. If the responsibe party is a member of an OSRO that has a pre-existing agreement with a sateite imagery provider, it is ikey that the OSRO wi manage the imagery acquisition on behaf of the responsibe party as part of the SLA between the OSRO and the responsibe party. If the responsibe party is a member of an OSRO that has a pre-existing agreement with a sateite imagery provider but the responsibe party aso has its own agreement with a sateite imagery provider, the responsibe party wi need to decide which provider to use. If an agreement is not aready in pace, the responsibe party wi need to decide how to estabish one: If the responsibe party is a member of an OSRO that does not have a pre-existing agreement with a sateite imagery provider, the responsibe party wi need to either estabish an agreement directy with a sateite imagery provider or instruct the OSRO to estabish an agreement on their behaf as an additiona service. If the responsibe party is not a member of an OSRO, they may: estabish an agreement directy with a sateite imagery provider; or instruct an OSRO to estabish an agreement on their behaf, whie maintaining separation from the OSRO s other services. Utimatey it is the decision of the responsibe party to decide which sateite imagery provider shoud be used. The important provision is that an agreement is made by the SRS Coordinator, and that a stakehoders are made fuy aware of its existence we in advance of, and during, a spi. Working with reguatory and governmenta organizations During a spi, reguatory and governmenta organizations wi be present to monitor the progress of the response, ensure that a reguatory conditions are adhered to and report on the impact of the spi to the reevant authorities. In many paces, the government may even take the ead on managing the response. In either situation, the SRS Coordinator shoud take a proactive roe in engaging with the reguatory and governmenta organizations, providing the reevant imagery and information when requested to do so. By providing arge-scae synoptic coverage, sateite imagery is an important communication too that can be used in a response. However, it needs to be used carefuy. Distinguishing oi on an image often requires expert anaysis; any imagery provided to externa organizations (and reeased to the media and pubic) shoud therefore be accompanied by the instructions necessary to interpret what is shown on the image. Reguatory and governmenta organizations may aso be a source of sateite imagery. Those which have their own oi spi monitoring programmes may have provided the initia notification of a spi, and wi possess the origina image(s) in which the oi was detected. This is a key advantage of having an oi spi monitoring detection programme in pace, whether run by reguatory organizations or provided by a sateite imagery provider under contract to a specific company or customer. The origina imagery can be used to begin updating the sateite imagery pan and to hep seect the most suitabe technoogy for the response. 29

32 IPIECA IOGP The sateite imagery acquisition workfow As soon as a spi is reported, actions can begin to obtain sateite imagery for the response. Foowing the initia spi notification, the SRS Coordinator shoud begin image panning with the sateite imagery provider who wi then be abe to submit an order to the sateite operator as soon as it is authorized by the response. The imagery acquisition workfow The acquisition of sateite imagery forms a defined workfow (Figure 3). This can be used by the SRS Coordinator to outine to other stakehoders the timescae required for acquisition of the sateite imagery. Each step of the acquisition workfow is expained beow. Figure 3 Image acquisition workfow Spi notification The initia spi notification informs the responsibe party or OSRO that a spi has been detected. The spi notification is important for SRS as it provides detais of the ocation, incuding country or region, and coordinates of the spi, the type of area affected (e.g. inand, rivers, offshore, subsea, etc.), the date and time, and the source, cause and status of the spi. Environmenta (e.g. weather) and sea conditions may aso be given. These detais shoud be provided to the SRS Coordinator to hep with imagery panning. Image panning Using the information provided at the spi notification stage, the SRS Coordinator can update the sateite imagery pan and then consut with the sateite imagery provider to determine the most suitabe options and put together an order for the sateite imagery. Using image panning software, the sateite imagery provider wi determine the most appropriate technoogy to meet the requirements and priorities of the response, and wi agree this with the SRS Coordinator. This agreement between the SRS Coordinator and the provider, often known as the tasking handshake, is a critica step in the acquisition workfow. The Coordinator is responsibe for reviewing the tasking proposa, providing a map of the acquisition area, and reconfirming the AOI; this avoids any risk of the wrong area being targeted something that coud potentiay occur, for exampe if atitude and ongitude coordinates are inadvertenty misquoted. 30

33 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA The image panning software shoud take into account whether or not a sateite is avaiabe for tasking. Tabe 5 ists the main reasons why a sateite may not be avaiabe. Tabe 5 Factors affecting the avaiabiity of a sateite Factor Sateite/sensor avaiabiity Higher priority acquisitions Area Expanation There may be insufficient sateite resources avaiabe for acquisition due to maintenance and/or ongoing issues. A higher priority acquisition from another cient (e.g. miitary) may confict with the order. The target area may be restricted (i.e. acquisitions not aowed) due to security or for commercia reasons. As a resut, the image panning process may invove consideration of severa different potentia combinations of sateites to ensure that the optima imagery can be acquired; using a sateite imagery provider that has access to a wide seection of sateite options wi be beneficia for this process. Data ordering Once the most appropriate sateite(s) and operator have been identified, the imagery provider wi pace the order with the sateite operator. Orders which are required as a matter of urgency shoud be ceary marked with the appropriate priority eve for the attention of the operator. The initia order for an oi spi response shoud be given emergency or rush priority to ensure that the required imagery is acquired, processed and deivered as quicky as possibe. Priority orders are ikey to incur additiona costs but wi ensure that the imagery is acquired at the next suitabe opportunity. Tabe 6 expains the terms that are commony used to describe different priority eves for tasking the sateites; note that the terms used and the expected timings may differ between sateite imagery providers and aso between sateite operators. Tabe 6 Common priority eves assigned to the tasking of a sateite Priority eve Standard/non-time critica Time-critica Emergency/rush Expanation The order is agreed in advance (at east the previous day); acquisition occurs on a best effort basis, i.e. when the sateite next passes over the AOI and there are no other tasking conficts. Such orders can be superseded by higher-priority acquisitions. The order is agreed in advance and acquisition occurs during a pre-agreed date/time period. Such an order takes priority over non-time critica orders and can be guaranteed, but may sti be superseded by emergency orders. The order can be paced at 4 12 hours notice; acquisition occurs on the next avaiabe pass over the AOI. Such an order takes priority over a other orders. 31

34 IPIECA IOGP Sateite tasking and data acquisition If an order is accepted, the sateite wi be tasked to acquire data when it passes over the AOI on its next orbit. Sateite tasking ony occurs a imited number of times per day in set periods; these are known as the tasking windows. If an order is not accepted within a particuar tasking window, the response team wi need to wait for the next tasking window, which wi deay the acquisition of the imagery. MacDonad, Dettwier and Associates Ltd. Once the sateite is tasked, the next opportunity for imagery acquisition known as the acquisition window wi depend on where the sateite is in its orbit in reation to the spi. If the spi is just behind the sateite when it is tasked, the acquisition wi be deayed by at east the time it takes for a sateite to compete one fu orbit (~100 minutes). The acquisition of imagery may therefore take up to severa hours from the point of order, dependent on the spi ocation and the set-up of the sateite and its operation. The potentia deays shoud be considered when deveoping the sateite imagery pan (see aso pages 37 38). Onboard data recording and data downoad Sateites transmit the recorded data to the sateite operator by downoading it to an avaiabe ground station which is set up and ready to receive the transmitted data. If a sateite has an immediate ine of communication with a suitabe ground station as it passes over the AOI, it wi downoad the data amost immediatey. If there is no ground station in the immediate ine of communication, the onboard data recorder wi store the coected data and downoad it to the next avaiabe ground station. This can resut in a further deay in the imagery acquisition process. Initia data processing Once the data has been downoaded from the sateite, it wi then undergo initia processing at the preferred processing faciity (ocated either within the ground station or at a separate processing faciity). Due to the way in which the data are coected by the sensor, there wi aways be a need for a minimum eve of initia processing. The initia raw data acquired by the sateite known as a Leve 0 data product are not directy suitabe for oi spi response as they need to be converted from engineering units into geographicay positioned and caibrated geophysica units. Imagery providers therefore icense their products as Leve X products where X represents the eve of processing appied to provide an understanding of the processing that the data has undergone. Tabe 7 on page 33 describes common product eves and the respective processing that wi have been appied. For oi spi response, Leve 1B or Leve 2A/B products are the most suitabe. Leve 1B products can be used for standaone remote sensing appications, such as image cassification or the generation of anciary datasets. To use the imagery within GIS software and appications (such as the COP), it wi need to be geo-referenced, and therefore a Leve 2A/B product wi be required (the coordinate reference system used shoud be specified in the metadata or within the map). To ensure efficiency during processing, the product eve required shoud be predetermined during image panning. 32

35 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Tabe 7 Common sateite imagery product eves and processing appied Product eve Product type Processing appied Leve 0 Leve 1A Leve 1B Leve 2A Leve 2B Leve 3A Raw instrument data Reconstructed raw instrument data Geometric corrected and caibrated Geo-referenced Refined geo-referencing Gridded and quaity controed None Radiometric caibration; atmospheric correction Geometric correction; coud cover cropped Geo-referenced using standard cartographic map Geo-referencing using ground contro points Ortho-rectification (accounting for reief dispacement within imagery) Leve 3B/ Leve 4 At this stage in the workfow, the acquired imagery is ready for secondary processing and oi spi anaysis by the imagery provider, or the SRS Team if present. Oi spi anaysis Mode output; derived variabes Ony after initia processing shoud an SRS Anayst (with experience in using the data provided) interpret the imagery. This anaysis is ikey to be conducted by the sateite imagery provider uness the SRS Team has the capabiity, capacity and preference to process the imagery internay. Using image processing software, the SRS Anayst wi anayse the imagery and determine whether it provides a vaid indication of the presence of oi. The information that the SRS Anayst wi be expected to extract from the imagery incudes: the ocation of the spi(s); the extent of the spi(s); estimations of the surface area covered by the spi(s); other characteristics of the spi (if appicabe); identification of response resources and assets; and identification of fase aarms. Whie the anaysis of singe images can provide usefu information, it may be preferabe to use mutipe images and/or data types to confirm the resuts of the anaysis. The use of mutipe types of data, known as data fusion, can aso hep identify fase aarms within the imagery. Band cacuations for indices; overaying of imagery from mutipe sensors; modeing of data in imagery Beow: sateite poygons (shape fies) on a map dispay: the yeow, orange and red poygons iustrate the outine of the oi detected by the sateite; yeow and orange indicate a ow confidence of oi; red iustrates the SAR signature, indicating that this is a probabe instance of oi. RADARSAT-2 Data and Products MacDonad, Dettwier and Associates Ltd., A Rights Reserved. RADARSAT is an officia mark of the Canadian Space Agency. MacDonad, Dettwier and Associates Ltd. 33

36 IPIECA IOGP In addition to ooking for oi spis within the imagery, the SRS Anayst may aso create anciary datasets from the imagery to hep confirm the presence of oi. For exampe, the Normaized Difference Vegetation Index (cacuated using red and near-infrared waveengths) may be used in persistent inand spis to show whether areas have been inundated with oi. The index provides an indication of whether green vegetation is present or not, and by comparing baseine data with current imagery, the SRS Anayst can determine the ikeihood of oi by measuring the deterioration of the vegetation. The same imagery may aso be used to provide other types of information to the response, e.g. by identifying access routes, characterizing neighbouring infrastructure, and performing various panning activities. Once the imagery has been interpreted and the observations vaidated by aternative data sources (and by another SRS Anayst, if avaiabe), the data and various fina products shoud be created and provided to the response team. Fina product deivery The most common data that can be extracted from an image are: the imagery itsef; outined/digitized oi sick features; estimations of oi sick areas; identification of assets and/or response operations; and anciary information on environmenta conditions, hazards and other man-made infrastructure (if appicabe). Depending on the response requirements, these data can be provided as a variety of fina products in different output formats, from hard copy imagery and maps to data fies and data streams. In genera the COP wi determine the output format of the fina products provided as we as the specification and detais of these output formats (e.g. tempates and standards that shoud be used for both the data and its metadata). The Open Geospatia Consortium (OGC) provides industry-wide recommendations on the standards and formats that shoud be used when using spatia data; further expanation can be found in IPIECA-IOGP, 2015a. To ensure that the data are accessibe and usabe by the appropriate stakehoders during an oi spi response, data suppiers shoud be encouraged to provide fina products in common and, if suitabe, editabe formats. Tabe 8 on page 35 ists the recommended formats for each product type. To ensure that the data are received in an appropriate format, the sateite imagery provider shoud foow an agreed set of data management protocos and procedures. Providers shoud ensure that the formats are compatibe with the various different types of GIS and image processing software packages (incuding the different open source and proprietary systems), and that the data are accompanied by the information necessary to understand what is shown, the appropriate metadata, and instructions for use and/or icensing requirements. This wi aso hep to ensure that the fina products suppied can be integrated into the COP. 34

37 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Tabe 8 Recommended formats for fina data products Product type Usage Product requirements Formats Hard copy maps, imagery and photographs Printing Sharing within non-gis users (by emai, FTP etc.) Map features (tite, egend) Legibe tempate PDF PNG/JPEG (Sateite) imagery and photography (e.g. aeria, observer) Within GIS or imageprocessing software Geo-referenced Metadata GeoTIFF Images with geo-referencing data Other raster-based fies Other raster formats Oi sick features (digitized from imagery) Within GIS or imageprocessing software Geo-referenced Metadata Data attribute expanations Suitabe for end user: KML GoogeEarth Shapefie/GeoJSON/GML, GIS Other vector-based fies Geodatabases Web-based maps Share imagery/maps with non-gis users Expanation of what the maps show OGC compiant WMS, WFS, WCS, WMTS Create dashboards Cacuations, observations Share numerica and text data/information Data is accessibe within products Deimited text fies (CSV, DBF, TXT) Appropriate units provided Screenshot of Esri s web-based map integrating various data feeds during the Guf of Mexico oi spi in Esri 35

38 IPIECA IOGP In the absence of a depoyed COP, a GIS Speciaist shoud be responsibe for determining the preferred fina products and output formats. In this scenario, as GIS and other spatia-based software wi sti be used, the COP data management procedures and protocos shoud sti be foowed for the products and formats agreed upon, for exampe using map tempates for hard copy maps. Box 7 Creating a sateite imagery map tempate A common fina product that shoud be provided by the sateite imagery provider is a map derived from the sateite image which outines any oi spis present; if possibe, an estimation of the sick area shoud aso be provided. To ensure that a usefu map is provided, it is recommended that a map tempate be deveoped in consutation with the sateite imagery provider before imagery is provided preferaby as part of the sateite imagery pan or whie waiting for the imagery to be acquired. The key features of a map tempate are outined in Tabe 9 (beow) and an exampe is presented on the right. Standardizing the tempate wi ensure that the end users wi understand the imagery throughout the response. The imagery shoud be provided in either PDF or PNG/JPEG output format (which are easy to open on mobie devices and share) and in an easy-to-interpret presentation, with expanations to hep users understand what is shown. RADARSAT-2 Data and Products MacDonad, Dettwier and Associates Ltd., A Rights Reserved. RADARSAT is an officia mark of the Canadian Space Agency. Tabe 9 The key features of a map tempate Essentia features Desirabe features Optiona features The image Base map behind image, showing outine of potentia oi sicks (pus estimation of probabiity) The date and time the image was acquired The sensor/sateite used Cartographic information, incuding: projection; coordinate reference system; scae; north arrow Legend (if appicabe) Interpretation instructions An overview map (showing image scene ocation(s)) Estimations of sick area (if appicabe) Licensing instructions (if appicabe) Map graticues/grids Identification of assets (if appicabe) Labes on major andmarks and geographic references Anciary environmenta, hazard or infrastructure information 36

39 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Imagery acquisition workfow considerations Whie the imagery acquisition workfow is theoreticay a simpe step-by-step process, it is subject to a variety of factors that can hinder the speed at which an image can be acquired, as we as the usabiity of the data. These factors incude: turnaround time (ead and atency time deays); acquisition timings and revisit capabiities; and environmenta considerations. Whie these factors can, to an extent, be considered in advance, e.g. during the deveopment of a sateite imagery pan, each incident wi represent a unique scenario, with potentia unanticipated chaenges. As a resut, these factors wi need to be reconsidered when using SRS to understand the reaistic avaiabiity and usabiity of the acquired imagery, particuary when using it for timecritica missions. Data ead times and atency Throughout the acquisition workfow, there is potentia for deays to occur that wi increase the time it takes to acquire an image after the order has been paced. These deays can be categorized as: 1. ead-time deays: the time between pacing an order and the image being acquired by the sateite sensor; and 2. atency: the time between the image being acquired by the sateite sensor and the fina product being deivered. Lead time deays argey resut from having to wait for both the tasking and acquisition windows, i.e. waiting for the sateite to be at the right point of its orbit, first to be tasked, and then to be over the AOI. They can aso be caused by indecision on behaf of the response organization during the image panning stage, deayed contractua arrangements, or orders being rejected by the sateite operator. The atency is mainy due to the sateite waiting to downoad the data to the next avaiabe ground station; this is dependent on the distribution and avaiabiity of suitabe ground stations. In genera, northern ocations are better served as there is greater coverage by ground stations. Equatoria ocations are not as we served, and it can take up to 100 minutes for a sateite to communicate with a ground station. Access to ground stations can aso vary depending on the sateite operator. To minimize the potentia deay in downoading the data, the sateite imagery provider shoud try to use sateites and operators with good access to ground stations. The atency can aso be affected by the efficiency of data processing carried out by the sateite operator and/or sateite image provider, and whether the fina deivered product meets the needs of the response team. For exampe, data deivered without area cacuations or without enough information to enabe the response team to interpret the imagery wi be unikey to meet the immediate needs of the response; in such cases it may be necessary to repeat the imagery acquisition process. These deays can have a serious impact on the utiity of the imagery provided. For exampe, imagery is usuay needed before operations are panned and conducted each day, and any 37

40 IPIECA IOGP imagery acquired during the previous evening or overnight wi need to be deivered in time for the morning meeting; if the imagery is not deivered in time, it wi be redundant and serve itte purpose for the operationa response team. Time deays caused by the response can be managed and reduced by foowing the previous guidance on deveoping a sateite imagery pan (page 16) and pre-panning imagery (page 20). However, time deays caused by the sateite s operation cannot be reduced and wi therefore need to be taken into account when panning the use of the imagery for time-critica missions, such as initia assessment and eary operation panning. Expected data acquisition timings and revisit capabiity In addition to deays within the workfow, the tempora coverage of sateite sensors (i.e. when and how often data is coected) may affect the avaiabiity of imagery for acquisition. Due to their orbita paths, sateites coect data at imited times during the day, often foowing the same oca time across the gobe. Whie a response may prefer to have the atest information eary in the morning for initia briefings, it is possibe that the imagery may not be coected unti midday, hence the atest information may not be avaiabe unti the end of day. In addition, the revisit capabiity (i.e. how often a sateite wi pass over the AOI in a day) wi determine whether or not the required imagery can be acquired on the day the order is submitted. For exampe, if the response misses the ony acquisition window for that day, it wi need to wait unti the sateite passes over the AOI on the foowing day. The revisit capabiity increases with higher atitudes, thus the tempora coverage is higher for spis near the poes than it is for those near the equator. Both of these timing factors shoud be taken into account when panning imagery acquisitions and the depoyment of other assets, such as aeria surveiance. Environmenta considerations The usabiity of the acquired imagery can be affected by the environmenta conditions prevaiing at the time of the acquisition. Many sensors onboard sateites require particuar environmenta conditions to be present to effectivey detect oi on water; for exampe, a certain wave height is needed for some sateites to be abe to distinguish between oi and water. To overcome potentia issues with capturing poor imagery, particuar types of sensors shoud be used in different environmenta and weather conditions, such as rain, coud or ack of dayight. Whie it is the roe of the sateite imagery provider to determine the type of sateite used, it is important that the SRS Coordinator is abe to expain these issues to other stakehoders. For further information on the effects of environmenta conditions on the operation of different types of sensors see pages Managing the acquisition workfow The time period between the initia spi notification and the deivery of the fina imagery product is typicay quoted as 3 and 72 hours, however this can vary substantiay in practice. The precise timings of each stage wi differ for each response and each acquisition. Deays can be minimized by deveoping a sateite imagery pan which ensures that factors within the contro of the response team are pre-panned and we tested (e.g. by impementing procedures to submit an 38

41 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA appropriate order as quicky as possibe and to guarantee that the data are received in the correct format). To manage these potentia deays and the expectations of other stakehoders, the SRS Coordinator and sateite imagery provider shoud discuss and communicate the expected timings of acquisitions and downoads, and shoud update this information as necessary during the response. Box 8 Understanding the sateite imagery acquisition workfow in rea time To understand the sateite imagery acquisition workfow in greater detai, an anaysis was conducted by the OSR-JIP, in conjunction with eading sateite imagery providers, to compare and assess estimated ead times and atency for sateite imagery acquisition. This theoretica anaysis was supported by a reaword exercise, which tested the theoretica data ead times and atency periods. The OSR-JIP report (IPIECA-IOGP, 2015b) provides a numerica breakdown, which can hep to provide quantifiabe estimates for the time it may take to acquire sateite imagery. The anaysis aso ooked at comparing how the revisit capabiity and acquisition timings differed for various types of sateites, as we as how the environmenta conditions coud prevent certain types of sateites from being used. 39

42 IPIECA IOGP Using and communicating the imagery and data The fina product(s) shoud be deivered to the SRS Coordinator to manage, cataogue and share, as required by the response. These products wi be shared with the reevant stakehoders, who wi use them for a variety of tasks. As a resut, it is important that the fina products are easiy accessibe and usabe. The primary vehice for sharing the products is the COP; this is a repository of a the data generated within, or used by, the response, and usuay takes the form of a GISbased patform that can be used to visuaize mutipe geospatia datasets and maps in a userfriendy appication. The SRS Coordinator shoud therefore provide the fina products to those responsibe for maintaining and updating the COP within the Panning Section. This heps to prevent data from becoming inaccessibe or sioed, being misused, or simpy forgotten about. In addition, the SRS Coordinator shoud provide the Documentation Unit with origina copies of the fina products to ensure that they are recorded and archived as the response progresses. One key responsibiity of the SRS Coordinator is to ensure that the fina products are accompanied by compete metadata. The metadata shoud incude detais of who created the product and when, and the contact detais in case end users have any questions. Aso required is a compete description of the geodetic and, if appicabe, projected coordinate reference system (CRS) to which the data are referenced, the detais of the geo-referencing technique, and the estimated positiona accuracy of the data. More information on the use of metadata can be found in IPIECA- IOGP, 2015a. In addition to the metadata, the icensing detais and terms and conditions of use shoud be provided. Of particuar importance is the need to ensure that any sharing and subsequent use of the sateite imagery has been agreed to by the sateite imagery provider. Geo-referencing of sateite imagery Remote sensing data are typicay geo-referenced to a goba geodetic CRS or datum (e.g. WGS 84) and to a projected CRS of the end user s choice typicay the Universa Transverse Mercator (UTM) grid. During an oi spi response the remote sensing data wi need to be combined with asset ocation and other data in the GIS-based COP; these data wi normay be referenced to a oca geodetic CRS and may aso be referenced to a projected CRS that is not UTM-based. To map a data together so that they are correcty dispayed in a spatia sense, a coordinates/ positiona data need to be transformed and/or converted into a common CRS. Faiure to do this can typicay resut in errors of up to severa hundred metres between different data sets. Bringing a data onto the same CRS is, however, straightforward in principe and may often be carried out on the fy by the GIS. This woud normay be the responsibiity of the Geomatics Unit of the ICS (see IPIECA-IOGP, 2015a). However, the correct resut requires that the CRSs of a the different data types and sources are fuy defined and that the coordinate transformation parameters between the different geodetic CRSs/datums are known. This shoud aso be considered during the initia impementation of the COP. 40

43 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Licensing and sharing of imagery Sateite imagery providers wi provide a fina products imagery and data for use under a specific end-user icence agreement (EULA), which incudes the terms and conditions of use. The EULA wi determine by whom, and how, the fina products can be used and shared; the terms may differ between products and may aso change over the course of the spi and during the months that foow. The icensing terms and conditions most commony found in a EULA reate to: Attribution: does the product require attribution? Sharing: can the product be shared, internay or externay? If so, are there imitations? Derivatives: can other products be derived? If so, is an additiona icence required? Commercia use: can the product be used for commercia purposes? If so, are there imitations? Licensing The icensing of the imagery and data, aong with any terms and conditions of use, shoud be discussed with the sateite imagery provider before the agreement is put in pace; each stakehoder shoud have an understanding of how the imagery can be used before it is acquired. For exampe, the imagery provider may require attribution on any fina or derived products (from PDF maps to other datasets); this may be a ogo or statement of copyright, which may need to be reproduced at a specified size or in a certain ocation. If further data is derived from the fina products by the oi spi response team, the response organization wi need to ascertain whether these datasets can be used under the same icensing terms as the origina product. As the sharing of imagery and/or data is crucia for an oi spi response, any icensing terms shoud suit the response needs. For exampe, it is ikey that the imagery wi be used as a base map for operationa panning, whether as a map or data within a GIS appication, and thus shared with responders on-scene. Any icensing agreement shoud permit this type of interna sharing, as we as the sharing of the product in the various output formats. This is particuary reevant as more data are now becoming integrated into a COP and are thus avaiabe to a those working within the response who have the reevant access rights. Sharing of imagery A icence to share data externay shoud be mutuay agreed upon by the response and the imagery provider. The reease of accurate imagery and data at the appropriate times is vita for preventing pubic uncertainties about the effectiveness of the response. A information shoud therefore be checked with the SRS Coordinator prior to reease, and vaidated with other surveiance and operationa observations to ensure that it is correct. In addition, the imagery provider shoud be required to consut with the SRS Coordinator and Incident Command before making any imagery and/or data pubic. The SRS Coordinator shoud make sure that any icensing and terms and conditions of use reating to the sharing of imagery and data with externa stakehoders are stipuated ceary in the agreement and/or in the sateite imagery pan. 41

44 IPIECA IOGP Expoitation of the imagery and anciary data in a response The various stakehoders within the response wi use the imagery and data to fufi different purposes. As previousy stated, the three key missions that sateite imagery can hep with are: the initia detection and assessment of the oi spi incident; ongoing assessment and synoptic monitoring (incuding operations panning); and providing pre-spi and baseine data. Sateite imagery wi be used by different stakehoders for different purposes. This image was generated with imagery from NASA s MODIS instrument to show the extent of the oi spiage during the Macondo spi. NASA/GSFC, MODIS Rapid Response (pubic domain image via Wikimedia Commons) For each mission, the imagery and data can be used for a variety of appications by the various stakehoders within the response. Tabe 10 on page 43 outines many of the tasks that stakehoders may wish to conduct. Improving imagery provision during and after a spi As with any part of the response, the provision of imagery during a spi is ikey to encounter new chaenges and imitations, whether during the image acquisition process or in the use of the end products by stakehoders. As a resut, the SRS Coordinator shoud identify any issues with the current sateite imagery pan, determine how to improve the pan and, if required, communicate this to the sateite imagery provider. The SRS Coordinator shoud aso ask for feedback from those using the imagery and data. As the provision of imagery is a repeatabe process during the spi response, every reiteration can be improved immediatey by the communication of issues and feedback. The issues encountered, and feedback received, reating to the SRS capabiity shoud be recorded and then reviewed as part of the anaysis of essons earned, which is often conducted post-spi. The recommendations agreed upon shoud then be used to update and improve the existing sateite imagery pan, providing expanations or notes for future spis. 42

45 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Tabe 10 Potentia uses of sateite imagery and anciary data by different stakehoders in the response Potentia user Incident Command Operations Unit Panning/Situationa Unit Press/Media Team Lega Team Uses of imagery and data Uses imagery to determine and communicate the characteristics of the spi, incuding ocation, quantity estimations.* Uses spi features derived from imagery to overay on other datasets to provide situationa awareness, e.g. spi ocation compared to resources at risks, infrastructure, etc. Anayses and communicate the effectiveness of recovery methods by comparing the ocation/quantity of oi across time/severa images. Uses baseine imagery to determine the end of a response, comparing preand post-event conditions. Uses the imagery as a base map for panning operations, incuding panning surveiance overfights, and overaying current and future asset positions. Uses imagery (and derived data) to identify areas requiring oi spi ceanup, e.g. impacted shoreines. Uses imagery to monitor progress of operations, e.g. the progress or extinguishing of burns. Uses quantity estimations to determine the optima aocation of resources, e.g. the amount of dispersant or waste faciities required.* Uses baseine imagery to determine the end of cean-up operations, e.g. how cean is cean? Uses imagery to update current situationa awareness for the response, incuding extracting positions of assets and resources from high-resoution imagery. Updates existing forecasts and modes for the oi spi trajectory modeing. Uses imagery to show the initia ocation and extent of the spi and how this changes over its ifespan. Uses quantity estimations and imagery to show the effectiveness of the response operations.* Uses baseine and incident imagery to compare before and after, incuding carifying the impact of the spi and quantity estimations.* Uses spi features and imagery to show the trajectory of the spi over its ifespan and carify areas impacted. * See Box 2, Can (sateite) remote sensing determine oi thickness and type? on page 14. Storing and archiving imagery The SRS Coordinator shoud consut with the Documentation Unit to ensure that provisions have been made to store and archive the imagery and anciary data appropriatey during and after the spi. To hep the Documentation Unit, the SRS Coordinator shoud set up (in accordance with COP recommendations) suitabe data storage faciities that can be readiy accessed (e.g. by date, data type, sensor type, etc.), and shoud provide guidance on naming conventions, data formats and the storage of associated metadata. 43

46 IPIECA IOGP Due to the arge sizes of sateite imagery fies, it is important to have a centra data storage soution in pace before the imagery is deivered, in particuar to avoid exceeding storage quotas on emai systems or other persona storage devices. In addition, if a spi response is ikey to continue for an extended ength of time, it may be appropriate to archive imagery that is no onger current for day-to-day operations. In most incidents, it is recommended that data be archived on both physica and secure coud-based storage patforms. Any soution put in pace, incuding naming conventions, shoud be appied to any reguary-updated geospatia data made avaiabe to the response. By deciding upon, and setting up, these structures and faciities in advance, either as part of the sateite imagery pan or during the initia image acquisition, users wi be abe to access data quicky and accuratey. Furthermore, the avaiabiity of we-preserved and accessibe information after the incident wi aid in: training new responders and SRS team members in how to use imagery and data correcty; highighting issues during the anaysis of essons earned; and providing evidence for ater interna reviews and for potentia itigation issues. The SRS Coordinator shoud ensure that the icensing requirements aow the fina products and derived information to be used post-spi, and shoud note whether the icensing terms stipuate any additiona requirements for the storage and sharing of the imagery and associated data. Using sateite imagery as evidence for iega discharge Iega discharge from a vesse, detected by sateite radar Sateite imagery can be used to hep historicay trace the source of a spi. For exampe, for areas covered by oi detection monitoring programmes imagery may exist which contains evidence of when a spi was first detected; it might even be possibe to visuay identify the source of the spi from the imagery. In addition, for offshore spis, other data (such as that from Automatic Identification Systems) covering the same date and time can be used to connect a vesse path with a spi. This can hep to trace the origin of the spi and identify the responsibe party, and in some countries the imagery can be used as evidence for the prosecution in cases of iega discharge. The image on the eft shows an iega discharge from a vesse, detected by sateite radar. The back ine iustrates a trai of pam oi residue 30 km ong; the crew had been washing its tanks which had contained the oi. ESA 2012, provided by EMSA 44

47 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Understanding sateite technoogy for oi spi response Determining which sateite (or sateites) to use in a response wi primariy be the responsibiity of the sateite imagery provider. However, to expain to other stakehoders why certain sateites are used, or in some cases not used, for the response the SRS Coordinator requires a basic understanding of sateite technoogy and how the set-up of a sateite affects its suitabiity for use within an oi spi response. This section provides a brief introduction to sateite technoogy. For more information see the OSR-JIP report entited An Assessment of Surface Surveiance Capabiities for Oi Spi Response using Sateite Remote Sensing (IPIECA-IOGP, 2014a) and the API panning guidance entited Remote Sensing in Support of Oi Spi Response (API, 2013). The basics of sateite technoogy A remote sensing sateite consists of two main components: the bus or patform and the onboard remote sensors. The patform consists of the operationa equipment to keep the sateite running, e.g. fue, onboard computer, soar panes etc., and acts as the vehice to carry the onboard remote sensor which acquires the data and/or imagery. Each sateite is designed to fufi a pre-panned mission. The design determines how the sateite is set up (the patform used, the onboard sensors, the scanning mode of the sensors, the ange at which the sensor scans) and the orbit that the sateite has been paced into (e.g. orbit atitude and incination). In addition, the sateite may be designed to provide spatia coverage ony for certain areas. For exampe, the European Space Agency (ESA) Sentine-1 radar imaging sateites (which are designed to acquire data for input to ESA s Copernicus programme) ony offer spatia coverage to specific pre-seected geographica areas over the gobe. Sateite technoogy for oi spi response For oi spi response, the two primary factors that wi determine whether a sateite can be used are: 1) whether the type of onboard sensor wi be abe to acquire usabe imagery within the operating environment; and 2) whether the tempora and spatia coverage provided by the sateite wi meet the data requirements of the response. The atter is discussed briefy in the section on sateite imagery acquisition workfow on pages Types of remote sensors used for oi spi response Remote sensors produce imagery by using different waveengths within the eectromagnetic spectrum (see Figure 4 on page 46) to detect and measure different properties about the earth; these measurements are then recorded as pixe data and combined together to produce the imagery. 45

48 IPIECA IOGP Figure 4 The eectromagnetic spectrum Remote sensors measure these properties either activey or passivey, depending on the waveengths used. The differences between active and passive sensors are shown in Tabe 11 (beow). Tabe 11 The differences between active and passive sensors Passive sensors Active sensors Measuring method Process Advantages Limitations Passive sensors detect natura radiation emitted or refected by the targets or phenomena being observed. The visibe imagery is usuay simpe to process and interpret. Rey on externa sources to provide the energy and waveengths required for detection. Are subject to imitations on when they can be used, e.g. during dayight and cear weather conditions. Can be affected by weather conditions, e.g. radiation can be absorbed or distorted by couds, haze, etc. Active sensors emit their own puse of energy and then measure the signa that is refected back to the sensor. Rey on interna sources and, as a resut, are abe to operate during day or night, as we as during some adverse conditions. Can be configured to optimize the samping of the surface and focus the energy to achieve a high spatia resoution or to minimize atmospheric absorption. Are more compex than passive sensors in terms of technoogy, and create compexities and chaenges in the processing and interpretation of imagery. 46

49 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA The most common types of passive sensors used for sateite remote sensing for oi spi response are those that operate in the visibe, infrared and therma infrared bands. Sensors operating in these bands are known as optica sensors. The most common type of active sensor used for sateite remote sensing for oi spi response is radar, specificay synthetic aperture radar (SAR) which uses the microwave band. Each type of sensor uses a different region of the various waveengths within the eectromagnetic spectrum to measure properties about the phenomena it is observing (see Tabe 12). To detect oi, an SRS Anayst wi ook for variations within the measurements taken; whether these variations wi be visibe within the imagery wi be determined by the environmenta conditions. Tabe 12 The different types of sensors and their bands Sensor type Sensor band EM range What does it measure Visibe μm Refected sunight Optica (passive) Infrared Therma infrared Near = μm Short wave = μm μm Naturay emitted radiation Surface temperature Radar (SAR) (active) Microwave X-band = 8 12 GHz / cm C-band = 4 8 GHz / cm L-band= 1 2 GHz / cm P-band = Ghz / cm Radar backscatter Using optica and radar (SAR) sensors for oi spi response The different types of sensors avaiabe for sateite remote sensing are subject to a range of operationa sensitivities to environmenta conditions. This wi have an impact on whether each type of sensor wi be suitabe for use in a particuar oi spi response operation. The type of sensor most appropriate for the response wi first be determined by the ocation of the spi, and then by the weather and operating conditions. Location of an oi spi The ocation of an oi spi wi determine the type of surface on which the oi has been spit, e.g. water in offshore spis, sand for shoreine or inand spis, or even ice-covered water in higher atitudes. For sateite remote sensing, ony specific types of sensors wi be appropriate for use over each of these surface types. In addition, the variations that SRS Anayst wi be ooking for within the acquired data may be different depending on the surface being anaysed. 47

50 IPIECA IOGP Offshore spis / spis on water Most experience in the appication of SRS for oi spi response has been gained in the offshore environment. The contrast between oi and water is great enough to enabe much of the eectromagnetic spectrum to be used to detect oi spis. Each type of sensor has been proven to provide basic detection of oi on water, and in some cases they can aso detect other characteristics such as the oi/water ratio. Tabe 13 summarizes the data captured by the most common types of optica and radar sensors; these data are used by the SRS Anayst as the basis for identifying potentia oi spis offshore. Tabe 13 Remote sensors for oi spi detection in offshore ocations Sensor type Sensor band How the sensor detects oi Optica (passive) Radar (SAR) (active) Visibe Infrared Therma infrared Microwave Coour/ non-specific absorption Sun-gint on water Absorption at specific waveengths (0.8, 1.2, 1.73 and 2.3 μm) Temperature of spi area reative to surroundings (e.g. oi retains heat better than seawater and appears warmer in the eary evening) Changes in surface roughness (i.e. gravity waves, capiary waves) caused by the damping effect of the spied oi The SRS Anayst wi ook for variations in the acquired imagery as evidence of spied oi; it is therefore important to note that these variations may not be ceary visibe in the imagery if the environmenta conditions are not optimum for the chosen sensor. Furthermore, the SRS Anayst wi need to be aware of potentia fase aarms that may be present within the data. The common causes of fase aarms for the different sensors and bands are outined in Tabe 14. Tabe 14 Potentia fase aarms, by sensor/band, in the offshore environment Synthetic aperture radar (SAR) Therma infrared (TIR) Short-wave infrared (SWIR)/ near infrared (NIR) Visibe ight (VIS) Bioogica Biogenic sicks, minera ois Biogenic sicks, minera ois, weed and kep beds, refected sunight Oceanographic Freshwater pumes, fronts, interna waves Upweing, water infows, fronts Bathymetric Shaow water moduation Shaow water feature Atmospheric Variabe surface wind stress, rain ces, wind shadows Coud shadow Man-made Turbuent ship wakes Man-made heat sources 48

51 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA As the various sensors/bands are sensitive to different phenomena that may present themseves within the imagery, the use of different types of imagery (e.g. optica as we as SAR) can be effective in distinguishing oi spis from features such as wind shadows (which are often misinterpreted as oi spis in SAR imagery). It is important that an SRS Anayst interpreting the imagery is aware of the types of fase aarms that may be present for the spi ocation. One strategy to hep the SRS Anayst is to buid up a picture of fase aarm patterns that may occur in simiar offshore ocations and for particuar sensor types. Onshore (inand) spis The use of sateite remote sensing for the detection of oi onshore, and in rivers and estuaries, is not as we estabished as it is for offshore spis. These environments are often highy variabe with different types of surfaces present, incuding sois (at varying eves of saturation), varying densities of vegetation cover and the presence of water. These varying conditions can ead to arge numbers of fase positives, thereby increasing ambiguity in the interpretation of imagery, particuary when using SAR sensors. As a resut, airborne surveiance is a more reiabe technique for detecting surface oi in the onshore environment, and the use of sateite remote sensing for the emergency detection of inand oi spis is not recommended. SRS can, however, be used for the indirect detection of oi spis, using methods such as studying stressed vegetation, or using change detection agorithms. Furthermore, during a spi, optica SRS imagery can be used to provide up-to-date information on oca conditions to support the response, such as information on access routes, or on environmenta conditions such as and cover. Spi on ice / ice-covered water It is possibe to use sateite remote sensing for detecting spis on ice or ice-covered water in certain environments: In cases where the oi spi is in an area of open water that has ess than 30% ice coverage, the spi wi be detectabe by a sensors discussed above abeit ess easy than on water aone. In areas with more than 30% ice coverage, detection becomes more chaenging. Usuay ony optica sensors are used; if the oi is between the ice foes, the ice signatures can overwhem and compicate the oi signature within SAR imagery. However, some speciaists such as the Canadian Ice Service are increasingy abe to distinguish oi from ice. For oi on top of the ice, optica sensors can be used to detect oi. For oi encapsuated within or trapped under ice, there is no proven method of using SRS to detect the oi. Exampe of oi in sea ice The effective use of SRS for detecting oi spied on ice or ice-covered water wi depend on the environmenta conditions being suitabe. In particuar, for spis in higher atitudes, the oss of dayight in winter months and the presence of adverse weather conditions wi imit the efficiency of optica sensors. USGS/Creative Commons 49

52 IPIECA IOGP The use of SRS for detection of oi in ice environments is covered in more detai in the IOGP report on oi spi detection and mapping in ow visibiity and ice (IOGP, 2013). The report provides an evauation of current technoogy avaiabe for ow visibiity and ice surveiance together with recommendations for impementing SRS in these environments. Operating environmenta conditions Once the ocation has been taken into account, the main driver determining the most appropriate type of sensor wi be the operating environmenta conditions. These incude the: presence of dayight; presence of coud cover; presence of adverse weather conditions (e.g. rain, fog, haze, snow); sea conditions (offshore spis); and presence of ice. Tabe 15 summarizes the effects of environmenta conditions on the different types of sensors. In genera, passive (optica) sensors are unabe to operate at night, in coudy conditions, and/or in poor weather. SAR (an active sensor) does not rey on the presence of dayight for a source of radiation nor is its microwave signa impaired by atmospheric conditions. Ony very cam or rough seas and the presence of ice restrict the use of SAR for SRS in the offshore environment. As a resut, SAR sensors are usuay the go-to sensors for use in SRS operations for oi spi response in an offshore environment. It is important to note that whie optima SAR acquisition modes are avaiabe in theory, in practice the response team wi often need to take whatever acquisition modes are avaiabe based on the recommendations of the sateite imagery provider. Tabe 15 The effects of environmenta conditions on the operation of different types of sensors Synthetic aperture radar (SAR) Therma infrared (TIR) Short-wave infrared (SWIR)/ near infrared (NIR) Visibe ight (VIS) Dayight Works both day and night Works both day and night with cear skies Works in dayight hours ony (VIS, NIR) Works in dayight and dusk hours ony (SWIR) Coud cover Works in coudy skies Works ony in cear skies with imited coud cover Adverse weather (coud, rain, fog) Works in coud, rain or fog Wi not work in adverse weather SWIR works in hazy or foggy conditions Wi not work in adverse weather Sea conditions Wi not work we in very cam seas (<3 m/s) or rough seas with wind speeds >12 m/s Wi not work in very rough seas Ice Wi not work we in open water with ice concentrations >30% or on ice Wi work in most ice environments, except when oi is encapsuated in or under ice 50

53 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Key imagery characteristics The remote sensor equipment onboard a sateite wi determine the type of imagery acquired as we as key imagery characteristics such as the spatia resoution, spectra resoution and radiometric resoution (see Tabe 16). These characteristics are specificay designed by the sateite operator, based on the operator s understanding of the data requirements that the mission needs to fufi. Tabe 16 Definitions of key imagery characteristics of sensor technoogy Characteristic Definition Metric How does it affect the imagery? Spatia resoution The minimum distance between two targets that aows them to be separatey detected or resoved Distance (m/pixe): High: m Medium: 4 30 m Low: 30 >1,000 m If the resoution is not high enough, the sensor may be unabe to discern sma objects or phenomena, e.g. separate sicks. Spectra resoution The number of discrete spectra bands in which the sensor can coect refected radiance. Number of bands: High: 100 bands Medium: 3 15 bands Low: 3 bands Mutipe bands can provide more information; however ow spatia resoution is sometimes required to reduce noise in imagery. Radiometric resoution The number of eves of energy recorded, per pixe, in each spectra band. If the resoution is not high enough, the sensor may be unabe to distinguish between the different eves of refected, emitted and scattered radiation. Swath width (aso partiay determined by the sateite s orbit geometry) The distance that can be covered by a sensor in a singe scan as it orbits aong its path. Metre/kiometre The sensor may not cover enough of the AOI this can be overcome by constructing a mosaic of imagery from parae, previous or subsequent paths over the AOI. Tabe 17 Imagery characteristics for each sensor/band type Synthetic aperture radar (SAR) Therma infrared (TIR) Short-wave infrared (SWIR)/ near infrared (NIR) Visibe ight (VIS) What does it measure? Radar backscatter Surface temperature Natura emitted radiation Refected sunight Spectra resoution Waveengths No. of waveengths L to X band 1 (mutipe poarizations often avaiabe) μm NIR: μm SWIR: μm μm n/a High resoution: ~3 to 8 Medium resoution: ~7 to ~230 Spatia resoution ~1 to ~500 m n/a High resoution: <1 m to ~10 m Medium resoution: ~10 m to ~1 km Swath width ~5 to 500 km n/a High resoution: ~10 to 90 km Medium resoution: ~30 to ~60 km 51

54 IPIECA IOGP When determining an appropriate sateite/sensor technoogy for use in the response mission, the sateite imagery provider wi take into account the needs of the mission to determine the type of imagery characteristics required. For exampe, for a genera response, medium-to-high resoution imagery wi be required (to distinguish between different sicks and between other objects), with a swath width that preferaby covers the entire spi. However, as Tabe 17 on page 51 shows, the disparity between the imagery characteristics provided by the different types of sensors is not particuary great, and the main concern for the sateite imagery provider wi sti be to ensure that the most appropriate type of sensor is used according to the response scenario, e.g. with regard to the ocation and prevaiing environmenta conditions. Spatia and tempora coverage In addition to choosing the most appropriate sensor for the ocation and environmenta conditions, a further consideration that the sateite imagery provider wi take into account is the tempora and spatia coverage provided by the sateite. The tempora resoution describes when, and how often, the AOI can be imaged by the sateite; these characteristics are known as the acquisition timing and revisit frequency, respectivey, and are described beow: Acquisition timing: SAR sateites can expoit both day and night passes, and are therefore abe to sampe the AOI twice a day once on the ascending orbit and once on the descending orbit. For ow atitudes, this diurna samping is constrained to two short time periods, usuay eary morning and ate afternoon; higher atitudes have a more diffused range of samping times athough these sti take pace around the eary morning and eary evening periods. By comparison, optica sateites generay acquire imagery between am and 1.00 pm oca time on the descending orbit; the ack of dayight on the ascending path rarey aows the acquisition of usabe imagery. A sateites in near-poar orbits have a greater range of timings in higher atitudes then in equatoria regions due to the increased revisit frequency (see beow). Revisit frequency: Higher atitudes are ikey to be imaged more frequenty than equatoria ocations due to the increasing overap in adjacent swaths. The revisit frequency wi aso depend on the sateite parameters; for exampe, RADARSAT-2 can acquire data in the near and far ranges, which provides more opportunities for revisiting the AOI. Sateite consteations can achieve significanty higher revisit rates due to the use of mutipe patforms working coectivey; for exampe, the DigitaGobe consteation (consisting of the WordView-1, GeoEye-1, WordView-2 and WordView-3 sateites) is abe to image an AOI at any time between 9.00 am and 3.00 pm oca time. The sateite imagery provider/sateite operator wi provide advice on the revisit frequency of the various patforms recommended for the response. Further information, incuding maps that depict the revisit frequencies of major SAR and optica suppiers, can be found in IPIECA-IOGP (2014a). The spatia coverage per orbit wi be determined by a combination of sensor ange, scan mode and the orbit atitude, which resuts in a specific remote sensing geometry that wi determine the swath width of the sateite (see Figure 5). A arger swath width wi aow the sateite to cover more area as it buids up its imagery; however this can often be to the detriment of the eve of detai (spatia resoution) that the sateite can provide. 52

55 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Figure 5 Remote sensing geometry Other operationa considerations The operationa advantages and disadvantages of each type of sensor shoud aso be considered. In genera, imagery produced by sensors that operate on the visibe band (i.e. those that measure refected sunight) are the simpest to interpret, whereas the interpretation of SAR and therma infrared imagery wi require a higher eve of expertise. Overa, the sateite imagery provider wi take into account a of these factors when panning the most appropriate sateite or combination of sateites to use to acquire imagery for the oi spi response operation. Using mutispectra and hyperspectra sensors for oi spi response There is growing use of mutispectra and hyperspectra sensors for oi spi response. These sensors integrate mutipe bands of waveengths between the utravioet, visibe and infrared waveengths to determine specific spectra signatures (i.e. unique fingerprints ) for oi. Broadband mutispectra sensors are designed to use a reativey sma number of discrete bands (between 4 and 50) within specific waveengths. Hyperspectra sensors use more than 100 bands at different optica waveengths (incuding therma infrared) to determine the spectra signatures. Their spatia resoution is reativey coarse, however they provide a wide range of spectra frequencies that can be usefu in detecting and, in some cases, characterizing oi. 53

56 IPIECA IOGP MODIS (Moderate Resoution Imaging Spectroradiometer) image of the Guf of Mexico oi spi in MODIS is an exampe of a broadband mutispectra sensor, with 36 spectra channes. B.A.E. Inc./Aamy Stock Photo High-resoution mutispectra sensors can achieve a higher spatia resoution but wi have imited spectra samping ony in the visibe and near-infrared wavebands; as a resut they are ony effective when used in dayight, coud-free conditions. The coection of data across mutipe spectra ranges can reduce the ikeihood of fase positives; however, the voume of data generated is extensive and post-processing can be time-consuming, resuting in onger turnaround times for data as we as requiring greater technica skis. In addition to mutispectra sensors, muti-sensor sateites are avaiabe that combine severa different sensors, such as utravioet and therma infrared, to improve the detection of oi and reduce the ikeihood of fase positives. However, these combinations of sensors are sti subject to the same imitations as the individua sensors. More information can be found in the API report on the use of remote sensing in oi spi response (API, 2013). Innovation in sateite remote sensing technoogy for oi spi response Beyond the innovations in the use of sensors, advances in the operation of sateites shoud further improve the utiity of SRS for oi spi response, incuding: Launching smaer sateites: sma sateites can be aunched quicky and in significant numbers to significanty enhance samping of the surface. The creation of sateite consteations: a growth in the use of sateite consteations wi enhance the overa revisit capabiity, incuding potentia daiy revisits from high-resoution optica imagery (subject to weather conditions). Furthermore, if the sateites are networked, data can be sent between them, aowing the sateite nearest to a ground station to downoad the data, thereby reducing the waiting time for a downink. Buiding more ground stations: more ground stations both permanent and portabe wi ead to improved data turnaround times. 54

57 SATELLITE REMOTE SENSING OF OIL SPILLS AT SEA Artist s impression of the Terra Bea SkySat Consteation 2016 Terra Bea. A Rights Reserved. In addition, the OSR-JIP report entited Surface Surveiance Capabiities for Oi Spi Response using Remote Sensing (IPIECA-IOGP, 2015b) recommends that the oi industry focus for the future shoud be on the use of SAR technoogy for oi spi response for the foowing reasons: Sensors using new bands (L and S) wi be avaiabe in the coming years: it is anticipated that these wi eventuay become as widey avaiabe as existing C and X band sensors, hence the industry shoud become more famiiar with this type of data for use in oi spi response. In particuar, the potentia advantages and imitations of these frequencies shoud be evauated to assess their abiity to detect oi spis. New capabiities of poarimetric SAR an advanced imaging radar system shoud be evauated: this may be of vaue for oi spi characterization as we as detection, for exampe to hep discriminate between sheens and thicker oi, or to offer greater sensitivity for detecting oi in ice. Further information on these innovations is provided in IPIECA-IOGP, 2015b. 55