This proposal addresses the ROSES-2006 call for the algorithm refinement and Cal/Val activities for EOS MODIS and for Earth System Data Records (ESDR). The PI is a current member of MODIS, NPP and GOES-R science teams, and of the VIIRS Operational Algorithm Team (VOAT).
This proposal capitalizes on our progress achieved in the past two years. 1) A new advanced atmospheric correction algorithm for MODIS has been developed. It includes: a new gridding algorithm that effectively increases spatial resolution of MODIS L1B data and corrects known problems; a new cloud mask over land, significantly enhanced by the use of the image texture information; and a new atmospheric correction algorithm retrieving surface BRF/albedo from the TOA radiance. 2) A new global validation system for surface BRF/albedo - AERONET-based Surface Reflectance Validation Network (ASRVN) - has been developed. The ASRVN collects operational MODIS and MISR L1B data worldwide for small areas centered on AERONET sites, and uses AERONET aerosol and water vapor information to perform accurate atmospheric correction. The ASRVN products were used to validate MISR operational BRF and albedo products. 3) By its nature, the ASRVN is uniquely poised for the instrument calibration support. Recently, we characterized calibration difference between MISR and respective TERRA MODIS land channels� L1B reflectance. The MISR-MODIS difference found in the band gain coefficients is +6% in the blue, +3% in the green and red bands, and +1% in the NIR. The calibration difference leads to the systematic MISR-MODIS difference in the surface spectral albedo of +(0.01-0.03), which hinders the multi-sensor data fusion analyses.
We propose: 1) to finalize operational aspects of the new algorithm and demonstrate operational application by reprocessing MODIS and SeaWiFS data; 2) to conduct comprehensive comparison of the new algorithm with current operational MODIS aerosol and atmospheric correction algorithms; 3) to demonstrate improvements in the MODIS level 2-3 products; 4) to perform cross-calibration analysis between MODIS TERRA and AQUA, MISR and SeaWiFS instruments with the goal of developing the long-term climate quality ESDR; 5) to continue NPP/NPOESS VIIRS aerosol and atmospheric correction algorithm support through NASA science team and VOAT, and to provide surface/aerosol EDR validation support with ASRVN.
