Coral Reef Remote Sensing

Transcription

1 Coral Reef Remote Sensing Spectral, Spatial, Temporal Scaling Phillip Dustan

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4 Sensor Spatial Resolutio n Number of Bands Useful Bands coverage cycle Operation Landsat 80m Thematic 30m Mapper SPOT pan SPOT XS 20m IRS 6m CZCS 1km approx SeaWiffs 1km 8 6 Daily 1997 AVHRR 1km 4 2 Daily 1972

5 IKONOS Launch Date September 24, 1999 Athena II Vandenberg AFB, Ca Ground resolution of each band: 1-meter panchromatic < 26deg off nadir 4-meter multispectral < 26deg off nadir The ground processing software has the capability to rapidly process and mosaic imagery so as to create seamless image products with a consistent pixel ground sample distance (GSD)

6 IKONOS Relative Spectral Response and Radiometric Imagery Spectral Response Panchromatic: microns Multispectral: #1: Blue #2: Green #3: Red #4: Near IR Spectral Bands same as Landsat TM 4&5 Bands #1-4

7 Swath Widths & Scene Sizes Nominal swath width: 11 km at nadir Areas of interest a nominal single image 13 km x 13 km Strips of 11km x 100 km up to 11km x 1000 km Image mosaics of up to 12,000 sq.km. Up to two 10,000 square kilometer contiguous in a single pass within a region Metric Accuracy 12-meter horizontal and 10-meter vertical accuracy with no ground control 2-meter horizontal and 3-meter vertical accuracy with ground control (Specified as 90% CE (circular error) for the horizontal and 90% LE (linear error) for the vertical.

8 Orbital Information 98 Minute Sun synchronous Agile spacecraft in-track and cross-track pointing Altitude 423 miles / 681 kilometers Inclination 98.1 degrees Speed 4 miles per second / 7 kilometers per second Descending nodal crossing time 10:30 a.m. Revisit frequency for targets at 40 degrees latitude 2.9 days at 1-meter resolution; 1.5 days at 1.5-meter resolution Revisit times will be more frequent for higher latitudes and less frequent for latitudes closer to the equator.

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11 Mapping How do we detect and differentiate between major groups of reef communities: Coral Seagrasses Sand Rubble Hard algal pavements

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14 Wavelngth SeaWiFS Algal Photosynthetic Animal Interest Fluorescence (nm) Type Pigment All Chlorophyll a Absorption max Brown Fucoxanthin, Peridinin Absorption max Blue-green Type 1 peak ** 500 Green Type 2 peak ** Blue-green Type 1 shoulder** 515 Green Type 3 peak ** 540 Red, Phycobilins Bluegreen, CZCS hinge point 570 Red Phycobilins Absorption max Brown Chlorophyll c Absorption max All Chlorophyll a Absorption max 683 All Chlorophyll a Natural Fluorescence All Chlorophyll minimum Chlorophyll reflectance 765 Atmosphere 865 Atmosphere

15 Radiometric vs GIS Approach Classification of different habitat using cluster analysis - cluster busting approach Detection of habitats using analytical radiometric techniques Combine radiometric and GIS spatial/textural target identification Identification of threats and water qualities Merge with other types of sensors

16 How do we detect differences in coral reef condition? Colony level - scale too small Community/ ecological zone: Bleaching - albedo change algal abundance- albedo spectral textural

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21 Video Transects 3 video transects per station 3-5 minutes of tape per transect 120 images per transect 180 non-overlapping images sampled per station

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26 Wavelength Landsat 1 TM / Ikonos Spot pan 1 SPOT xs 1 JERS IRS 1 IRS-2S AVHRR 2 Panchromatic Blue * Green * * Red * * Infrared Infrared Infrared Infrared Pixel at nadir 80m 30m 10m 20m* 5.8m 5.8m? 1km 1 Sabin, 1996, 2. Kidwell, 1983,

27 Florida Keys

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36 Put reef map here For keys as a whole system

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42 Reef Variability: Temporal Texture

43 Coral Reef Degradation Carysfort Reef, Florida Keys, USA 60 KEY: algae substrate coral-dominated sand Live coral cover per year Percent Coral Year satellite in situ 1984 Landsat-Classified Image 1999 Landsat-Classified Image Satellites can provide an accurate synoptic time series of coral reef degradation from space corroborating in situ data. David Palandro, Serge Andréfouët, Phillip Dustan, and Frank E. Muller-Karger

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45 Reefs at Risk

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48 African Dust

49 Spectral Signatures

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52 Wavelength (nm) CZCS SeaWifs Blue ) Green ( ) Red ( ) Infrared 865

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56 OCTS Bbdview.jpg

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61 Mesoamerican Barrier Reef

62 Modis

63 MODIS: Mesoamerican Atolls

64 urbanization M a n predation predation Carnivores predation Sediments attenuation & smothering Disease infection Inorganic Nutrients photosynthesis Phytoplankton eutrophication attenuation Herbivores herbivory Benthic Algae competition Reef corals Meteorological Perturbations:temperature, turbulence, UV, etc

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66 Thanks for listening