MAPPING GLOBAL PHOSYNTHETICALLY ACTIVE RADIATION OVER LAND AND OCEANS USING MODIS PRODUCTS

摘要

The paper describes a method to generate global maps of the Photosynthetically Active Radiation (PAR). The process uses MODIS Top Of Atmosphere (TOA) radiance, higher level MODIS products (cloud fraction, surface Bi-directional Reflectance Distribution Function and Bi-Hemispherical Reflectance) and other data on surface wind speed, ozone and water vapour. The method consists in estimating the most important physical factors that determine the PAR intensity and then to perform a forward calculation of the daily integrated PAR. In particular, the Aerosol Optical Thickness (AOT) and Cloud Optical Thickness (COT) are retrieved from TOA radiance in MODIS band 3. First results are presented.