Assessment of HF Radar for Significant Wave Height Determination. Desmond Power VP, Remote Sensing, C-CORE

Transcription

1 Assessment of HF Radar for Significant Wave Height Determination Desmond Power VP, Remote Sensing, C-CORE

2 Study Rationale Agenda Technology Overview Technology Assessment for CNLOPB Proposed Go Forward

3 Study Rationale Sikorsky S-92A rated to Sea State 6 (4-6m) No flights above SS6 Sea state measurements available at rigs and on-shore No sea state measurement between platforms and shore Networks of wave buoys are rather impractical considering the required areal coverage Is there an alternative technology?

4 HF Radar Technology Crombie observed peaks in HF radio wave echoes in 1955 Observed Doppler shift in the radar echo Concluded it was from ocean gravity waves Studies in the 1970s showed relationship between radio signal backscatter and characteristics of gravity wave Surface currents, surface winds and surface waves could be derived

5 Study Objectives Investigate HF radar technology for measuring wave heights Demonstrate that technology works Can it work over the extended range required, >300km? Can it measure Sea State 6 and beyond? Use existing facility to baseline the capability What is the system configuration? What are the power levels? Where should the system be installed? What type of information can be supplied?

6 HF Radar Technology Overview

7 The Signal (from University of Hamburg)

8 Normalized Power Spectral Density Doppler Spectrum Doppler Frequency

9 HF Radars are known for Current Mapping Capability

10 C-CORE Research (Howell and Walsh, 1993) from Canadian Atlantic Storms Program (CASP, 1986)

11 Cape Race, Cape Bonavista DND Radars 200 meter contour

12 HF ROSA High Frequency Radar Ocean Surface Applications Objective: Real time knowledge of ocean surface conditions Argentia test site looks into Placentia Bay Project Partners MUN Faculty of Engineering MUN Physics and Physical Oceanography Northern Radar Inc

13 HF ROSA 2012 Field Program Placentia Bay

14 HF ROSA 2012 Field Program Placentia Bay Transmit Antenna Array

15 Receive Antenna Array

16 Currents from HF ROSA

17 Waves from HF ROSA

18 Technology Assessment

19 Sample WERA/Northern Radar Radar Spectra from Placentia Bay 11.7 km 59.7 km

20 Waves from HF ROSA Significant wave heights from the radar are within about ±0.25 m of the buoy readings Buoy Measured Waves: 1.28 m Buoy Measured Waves: 2.53 m Radar is here

21 Maximum Range Analysis MHz 10 Watts SWH = 2.3 m Range = 60 km Measured Second Order has 10 db SNR Can radar measure Sea State 6? What is radar range at Sea State 6? Use 7.7 metres as benchmark (~30% above SS6)

22 Maximum Range Analysis MHz 100 Watts 7.7 m waves Modeled Second Order has 10 db SNR 150 km when winds are along the radar look 110 km when winds are across the radar look 10 MHz 100 Watts 7.7 m waves Modeled Second Order has 10 db SNR 170 km when winds are along the radar look 120 km when winds are across the radar look

23 Coverage for 150km Radars ~150 km ~150 km

24 HF Oceanographic Radar Recommend operating in 10 MHz Frequency Range Antennas Receive antenna ~6m high guyed monopole Array of 12 elements Shore based 165 m long Production platform based ~100 m (7 elements), mounted underneath topsides 100 Watt transmitter

25 Coastline Concept

26 Platform Concept TX Array RX Array

27 Phase 2 Objectives Install a single dedicated shore-based HF Radar facility Facilitate access to data in near-real-time Operate facility for one year Demonstrate the performance of the radar Does it give the information you need Reliably Timely Accurately Is this better than what we had? Does this system introduce other problems? Interface with industry to integrate wave height data Make recommendations for a system that covers the full flight path from shore to platforms (Phase 3)

28 Prospective Site Bear Cove Point

29 Prospective Site White Hills