Comparison of NOAA NASA PAL and NOAA GVI data for vegetation change studies over China

Remotely sensed data, especially that from the Advanced Very High Resolutio n Radiometer (AVHRR), are increasingly being used to analyze changes in the global environment. This research analyzes two of the most commonly used r emote sensing data sets for global environmental change research, the Natio nal Oceanic and Atmospheric Administration's (NOAA) Global Vegetation Index (GVI) data and the new NOAA/National Aeronautics and Space Administration' s (NASA) Pathfinder AVHRR Land (PAL) data set, to determine if the new PAL data have successfully removed the major sensor-related problems found in t he GVI data. Principal Components Analysis of the data for the geographic r egion of China is used with results indicating that sensor-related problems remain in the PAL data, though not as severely as in the GVI data. For the time period of 1982 to 1992, the GVI and PAL data suffer from problems of spatial misregistration and radiometric miscalibration. The problem of orbi tal drift, however, has been minimized in the PAL data.