QUANTITATIVE ESTIMATION OF VARIABILITY IN THE UNDERWATER RADIANCE DISTRIBUTION (RADCAM)

1. QUANTITATIVE ESTIMATION OF VARIABILITY IN THE UNDERWATER RADIANCE DISTRIBUTION (RADCAM) Marlon R. Lewis, Principal Investigator Scott D. McLean, Co-Investigator Ronnie Van Dommelen, Senior Engineer Jianwei Wei, Ph.D. Student Ruby Quan, Master’s Student Brian Bylhouwer, Undergraduate Student May Hammad, Undergraduate Student Satlantic, Inc. & Dalhousie University

2. Measurement of the Radiance Distribution • For RaDyO we will develop and deploy novel instrumentation for the quantitative and radiometrically calibrated measurement of the time and depth dependent full radiance distribution fields in the upper ocean, which could be routinely deployed by the oceanographic community for subsequent scientific analyses of their sources of variability in a variety of water types.

3. Hyperspectral Profiler “HyperPro” Downward Irradiance Sensor Upward Radiance Sensor CTD, BB2/F, CDOM

6. Downwelling Spectral Irradiance Upwelling Nadir Radiance

8. Current Status • Preliminary data processed • Post-calibration complete (looks good). • Issue with upward irradiance sensor on surface float (shading?). Testing w/sensor on nose • Will reprocess with consistent tare and to evaluate new multi-cast approach to radiometric quantities & AOP estimation in upper ocean (see Zaneveld et al. 2001). • Completion estimated by 30 April, 2009 and data submitted to WOODS (and available to any/all).

9. Highly-Calibrated Optics Thanks to Ellie Speicher!

10. Status: Complete

11. Radiance Cameras • Profiling Upwelling and Downwelling Radiance Distribution Camera (RADCAM) • High scene-dynamic range (about 6 orders) • 550nm center wavelength, 20nm bandpass • Nominally 1 degree resolution at nadir • RADCAM on MASCOT • RADCAM on Bluefin • REFERENCE (Sky Radiance Distribution)

12. Reference Camera (SkyCam) Unfortunately, this camera failed during Santa Barbara experiment

13. ROV-RadCam Used as a Backup Reference Camera • Wet towel to keep ROV-Cam cool.

14. ROV-RadCam mounted on Mascot.

15. Above- and Below-Surface Images using ROV-RadCam on Mascot Images Brightened for Slideshow

16. ROV-RadCam Mounted on Bluefin

17. ROV-RadCam on Bluefin, Surfacing

18. RadCam-Pro (Profiling or Tethered) • Profiling RadCam with OCR504IR, CTD, and SeaRover. • View of SeaRover and upwelling camera.

19. Downwelling and Upwelling Images from Profiling-RadCam • Downwelling - overcast • Float (upper left of Snell) • Upwelling • School of fish affecting data • Downwelling - clear • KM (faint, top of Snell)

20. Downwelling Images from Profiling-RadCam

21. Snell Cone Fluctuations Depth = 1 m Figure 4: Simple representation of the light field variation across the Snell cone, showing fluctuations near the boundary due to waves and their evolution over time.

22. Downwelling Irradiance Validation with OCR504 and Radiance Distribution 20 10m 10 1 20m Radiance Scale uW/cm2/nm/sr 0.1 Kink in RadCam curve 30m 0.01 40m <0.001 50m

23. Downwelling Average Cosine and Diffuse Attenuation Coefficient Calculated from RadCam Images Due to kink in RadCam Ed curve

24. Upwelling Radiance Validation with OCR504 and Radiance Distribution 20 10 Problems 2m 1 Radiance Scale uW/cm2/nm/sr 0.1 6m 0.01 12m <0.001

25. Upwelling Irradiance Validation with Hyper TSRB

26. Upwelling Average Cosine and Diffuse Attenuation Coefficient Calculated from RadCam Images KLUcalculated from Hyperpro was about 0.14 for first 10m.

27. Status • Determine immersion coefficients for the cameras. • Do multiple system-calibrations for each exposure to better constrain cal data. • Find point spread-function for each camera. • Solve problems with the mid-radiance exposure data (such as that presented here). • Begin processing data captured with high-radiance exposure. • ….lots of work to do….good job Jianwei successfully defended his Ph.D. Qualifying Exam (November, 2009)!

28. Ready, Aye, Ready…for Hawaii! But…issue with unperturbed radiance field.