Mapping global land surface albedo from NOAA AVHRR

A set of algorithms is combined for a simple derivation of land surface alb edo from measurements of reflected visible and near-infrared radiation made by the advanced very high resolution radiometer (AVHRR) onboard the Nation al Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites. The system consists of a narrowband- to-broadband conversion and bidirecti onal correction at the top of the atmosphere and an atmospheric correction. We demonstrate the results with 1 month worth of data from the NOAA Nation al Environmental Satellite, Data, and Information Service (NESDIS) global v egetation index (GVI) weekly data set and the NOAA/NASA Pathfinder Atmosphe re (PATMOS) project daily data. Error analysis of the methodology indicates that the surface albedo can be retrieved with 10-15% relative accuracy. Mo nthly albedo maps derived from September 1989 GVI and PATMOS data agree wel l except for small discrepancies attributed mainly to different preprocessi ng and residual atmospheric effects. A 5-year mean September map derived fr om the GVI multiannual time series is consistent with that derived from low -resolution Earth Radiation Budget Experiment data as well as with a Septem ber map compiled from ground observations and used in many numerical weathe r and climate models. Instantaneous GVI-derived albedos were found to be co nsistent with surface albedo measurements over various surface types. The d iscrepancies found can be attributed to differences in areal coverage and r epresentativeness of the satellite and ground data. The present pilot study is a prototype for a routine real-time production of high-resolution globa l surface albedo maps from NOAA AVHRR Global Area Coverage (GAC) data.