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

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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


Measurement of the radiance distribution
Measurement of the Radiance Distribution RADIANCE DISTRIBUTION (RADCAM)

  • 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.


Hyperspectral Profiler RADIANCE DISTRIBUTION (RADCAM)

“HyperPro”

Downward Irradiance

Sensor

Upward Radiance Sensor

CTD, BB2/F, CDOM



Current status
Current Status Radiance

  • 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).


Highly calibrated optics
Highly-Calibrated Optics Radiance

Thanks to Ellie Speicher!



Radiance cameras
Radiance Cameras Radiance

  • 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)


Reference Camera (SkyCam) Radiance

Unfortunately, this camera failed during Santa Barbara experiment


ROV-RadCam Used as a Backup Reference Camera Radiance

  • Wet towel to keep ROV-Cam cool.



Above- and Below-Surface Images using ROV-RadCam on Mascot Radiance

Images Brightened for Slideshow




RadCam-Pro (Profiling or Tethered) Radiance

  • Profiling RadCam with OCR504IR, CTD, and SeaRover.

  • View of SeaRover and upwelling camera.


Downwelling and Upwelling Images from Profiling-RadCam Radiance

  • Downwelling - overcast

  • Float (upper left of Snell)

  • Upwelling

  • School of fish affecting data

  • Downwelling - clear

  • KM (faint, top of Snell)



Snell cone fluctuations
Snell Cone Fluctuations Radiance

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.


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


Downwelling Average Cosine and Diffuse Attenuation Coefficient Calculated from RadCam Images

Due to kink in RadCam Ed curve


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



Upwelling Average Cosine and Diffuse Attenuation Coefficient Calculated from RadCam Images

KLUcalculated from Hyperpro was about 0.14 for first 10m.


Status Calculated from RadCam Images

  • 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)!


Ready, Aye, Ready…for Hawaii! Calculated from RadCam Images

But…issue with unperturbed radiance field.


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