# Presentation: 209188

## Plans and Progress

- Kenneth Voss
- Howard Gordon
- Department of Physics
- University of Miami
- For Modis Science Team Meeting
- July 2004

## Slide 2

## STUDIES

- Sub-surface Bidirectional Reflectance distribution Function (BRDF)
- Morel’s Gothic R Factor
- Diffuse Transmittance (Corrected for BRDF)
- MODIS Instrument Polarization
- Coupled Ocean-Atmosphere Bio-optical Retrievals

## Bidirectional Reflectance distribution Function (BRDF) 

## Compared, favorably, the most recent Morel-Gentilli BRDF model with experimental measurements of the BRDF taken with the radiance distribution camera system (RADS-II). 
Plan to analyze data collected with the NuRADS camera system during the last several years to make an empirically based BRDF correction for clear water  — specifically for the MOBY site. 

- Plan to analyze data collected with the NuRADS camera system during the last several years to make an empirically based BRDF correction for clear water  — specifically for the MOBY site.

## Voss: open circles   Morel: filled squares

## Plan to analyze data collected with the NuRADS camera system to develop a turbid water BRDF — specifically data from the Chesapeake Bay. 
Plan to collect BRDF data on the upcoming Bouselle-AOPEX cruise with Andre Morel in the Mediterranean.  

- Plan to collect BRDF data on the upcoming Bouselle-AOPEX cruise with Andre Morel in the Mediterranean.

## If there are sufficient funds available, plan to collect BRDF data on a South Pacific Cruise with Andre Morel (Easter Island to Chile), covering the most oligotrophic waters known. 
We are expanding our measurements of the upwelling radiance distribution to look at the polarization of the upwelling radiance. 

- We are expanding our measurements of the upwelling radiance distribution to look at the polarization of the upwelling radiance.

## We Revisited Morel’s Gothic-R Factor

**We Revisited Morel’s Gothic-R Factor**

## Diffuse Transmittance (Corrected for BRDF) 

- If *L**u* is uniform,

## A

- D

- B

- C

- B

- C

- D

- B

***v*

***v*

***v*

***v*

- C ~ 0.3 mg/m3

*L**w*  Error (%)

- Radiance

*L**w*  Error (%)

## Slide 12

## MODIS Instrument Polarization Sensitivity

- Have been working on modeling the MODIS instrument polarization with others at Goddard.  Implementing the MODIS optics and thin film designs into an optical design ray tracing program (ZEMAX) and doing the polarization modeling in this program.  Hope to reproduce the pre-launch polarization data then investigate possible deteriorations in the MODIS instrument and its effect on the polarization sensitivity
- Developing technique for incorporating aerosol polarization in the polarization sensitivity correction section of the MODIS code.

## Coupled Ocean-Atmosphere Bio-optical Retrievals

- Atmospheric correction in dust.
- Atmospheric correction for Case 2 waters.
- Will be collecting Lidar data on aerosol vertical distribution during the upcoming Bouselle-AOPEX cruise with Andre Morel in the Mediterranean.

## Slide 15

## Year 2000: SeaWiFS Monthly Chl a

- mg/m3

- Standard Processing => Data Gaps due to Cloud/Dust Masking

**Notes:**
OC time series has big data gap during SW monsoon which has been a source of frustration for studies looking into characterizing seasonal cycles and interactions between physical forcing and biology

## Year 2000: SMA Monthly Chl a

- mg/m3

## Slide 18

## Slide 19

## Case 2 Waters

**Case 2 Waters**

## Chomko et al. 2003

- Chomko *et al. *2003