1. BACKSCATTERING OF SPECTRAL IRRADIANCE BY BUBBLES: HYCODE 2001 Marlon R. Lewis 1,2,Bruce Johnson 2,Alex Hay 2 1 Satlantic Inc. 2 Department of Oceanography Dalhousie University

2. Hypothesis: Bubbles injected into the upper ocean account for much of the backscattering of visible light, and variations in the backscattering coefficient in time and space. (Based on Mie scattering & radiative transfer theory Zhang et al. 1999, 2001) Dalhousie Univ. Satlantic Inc. Phase Function Spectral Reflectance Surface Radiance Amplitude and Angular Distribution BlueGreen Background

3. Matters arising….HyCode 2000 REMUS data analysis (K. Brown, Y. Huot, M. Lewis, and OSL/WHOI) Temp. Fluoro. K D (555) K Lu (555)

4. HyperPro: Sub-surface hyperspectral profiles (radiance/irradiance) + CT, Tilt SPAR: Surface hyperspectral upwelling radiance & downward irradiance, acoustics, camera, CT, GTD, tilt. HHS: Above-water hyperspectral upwelling radiance (overflights) HYCODE 2001: OVERVIEWVSM: Volume- scattering function continuous, joint w/ MHI & OSU. SQM: Intercalibration/ comparison (McLean)

5. Data Status: 1.HyperPro: Processed, available (http:/raptor.ocean.dal.ca/~mike/marlon) 2.SPAR Optics: Processed, available as above, acoustics in calibration. 3.HHS: Still being processed & interleaved with GPS 4.VSM: Processed, available as above & OSU web site 5.SQM: Data all processed, report available. Stations occupied from offshore blue to inshore brown waters. All instruments/ platforms functioned well – Thanks to Scott Pegau/CS STATION OVERVIEW

6. HyperPro: Provided useful hyperspectral downwelling irradiance/ upwelling radiance to >1% light level.

7. “Blue Water” Station“Green Water” Station HyperPro:

8. SPAR buoy provided hyperspectral upwelling radiance (0.6 m) and downwelling irradiance (above surface), along with multi- frequency acoustics, bubble camera, CT, tilts.

9. SPAR: “Blue Water” Station “Green Water” Station

10. 1.5 MHz 2 MHz. 4 MHz 300 kHz 350 kHz. 600 kHz SPAR: Multifrequency Acoustic View of Bubble Cloud (ship wake)

11. SQM: Overall, agreement between numerous instruments is excellent (see McLean report) 1. 48 independent instruments intercompared (including PHILLS (NRL)). 2. Hyperspectral and multispectral radiance sensors w/in 4%, in-water irradiance w/in 1%. 3. Above-water irradiance sensors more variable (9%). 4. PHILLS intercomparison with standard reference better than 7% w/ some roll-off near edges of target (WFOV). 5. Some processing uncertainties remain with other sensors (ASD, HOBILabs).

12. VSM: Deployed for continuous sampling (w/ OSU ac-9, others). 850 VSF observations over wide range of optical water types.

13. See Mobley et al. 2001 Boss and Pegau 2001

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