1. MODIS Science Team Mtg Simultaneous retrieval of Aerosol and Chlorophyll from MODIS Aqua radiances Clark Weaver GEST UMBC NASA Goddard Arlindo da Silva GMAO Radiative Transfer Dave Flitner Zia Ahmad Zia AhmadChlorophyll Watson Gregg

2. MODIS Science Team MtgIntroduction Goal : Construct algorithm that simultaneously retrieves Aerosol and Ocean Chlorophyll. Simulates observed MODIS radiances Observations, Reflectances 7 MODIS-Aqua level-2 channels (0.47 - 2.1um ) 2 Additional level-1b (0.412, 0.443, 0.488) Forward Model ● Aerosol 3D Transport MODEL (GOCART) provides spatial and size distribution of aerosols spatial and size distribution of aerosols  3D Ocean Biogeochemical model provides first guess chlorophyll concentrations (Watson Gregg) ● Herman Radiative Transfer Model (Vector Code) converts aerosol chlorophyll concentrations to reflectance

3. MODIS Science Team MtgMotivation Desire to retrieve absorbing aerosol information over Ocean using MODIS Radiances Need to account for chlorophyll absorption Approach: Use model based retrieval to use In Assimilation System

4. MODIS Science Team Mtg First guess 3D aerosol concentrations of Aerosol and Chlorophyll First Guess Reflectance AerosolOpticalParameters First guess Aerosol and Chlorophyll Retrieved Aerosol and Chlorophyll Analysis 3D aerosol And chlorophyll concentrations GOCART wfwfwfwf RETRIEVAL Adjust aerosol and chlorophyll MODIS Observed Level 2 and 1b Reflectance ρ o wawawawa RT Forward Model ρaρaρaρa ρfρfρfρf Biogeochemical Ocean Model

5. MODIS Science Team Mtg Many look-up-tables per MODIS channel generated by the University of Arizona radiative transfer model Variants: Aerosol species, Relative humidity Species Dust (dry R eff = 1.0, 1.4 µm) Seasalt (dry R eff = 1.0, 1.3 µm) Dust (dry R eff = 1.0, 1.4 µm) Seasalt (dry R eff = 1.0, 1.3 µm) Sulfate Black Carbon-Organic Carbon mixtures Sulfate Black Carbon-Organic Carbon mixtures Variant: Chlorophyll Spectral Absorption from Morel and Maritorena (2001) Spectral Absorption from Morel and Maritorena (2001) Variants: Underlying Surface Properties Rough Ocean (2, 6, 12 m/s wind speeds Ocean wind speed is from GMAO meteorological assimilation Ocean wind speed is from GMAO meteorological assimilation Radiative Transfer Forward model

6. MODIS Science Team Mtg Observed Radiance Analysis Chlorophyll Radiance term Total Analysis Radiance term mg /m3

7. MODIS Science Team Mtg Low Chlorophyll - Low aerosol

8. MODIS Science Team Mtg High Chlorophyll - High aerosol

9. MODIS Science Team Mtg Low Chlorophyll Moderate aerosol

10. MODIS Science Team Mtg High Chlorophyll - High aerosol

11. MODIS Science Team Mtg

13. How well can we simulate the observe radiances?

14. MODIS Science Team Mtg How well can we simulate the observe radiances?

15. MODIS Science Team Mtg Is the Analysis remembering the First Guess species distribution ? Black Carbon Organic Carbon Black Carbon Organic Carbon

16. MODIS Science Team MtgSulfateDust Is the Analysis remembering the First Guess species distribution ? SulfateDust

17. MODIS Science Team Mtg Sea salt

18. MODIS Science Team Mtg High AOD Solid chlorophyll = 0.04 mg/m3 Dashedchlorophyll = 0.20 mg/m3 Low Chlorophyll High Chlorophyll SSA=0.71 SSA=0.95

19. MODIS Science Team Mtg High AOD Moderate AOD Solid chlorophyll = 0.04 mg/m3 Dashedchlorophyll = 0.20 mg/m3 Low Chlorophyll High Chlorophyll SSA=0.71 SSA=0.95

20. MODIS Science Team Mtg Current Directions Developing Look-up-tables for absorbing aerosol and chlorophyll  Chlorophyll=0.1 Absorbing AOD=0.1   Chlorophyll=0.1 +  Absorbing AOD=0.1 Neural networks to replace Look-up-tables Model base retrieval algorithm

21. MODIS Science Team Mtg Chlorophyll (simulated) from Biogeochemical model 1 September 2001

22. MODIS Science Team Mtg