SOME CONSIDERATIONS FOR USING AVHRR DATA IN CLIMATOLOGICAL STUDIES .2. INSTRUMENT PERFORMANCE

A seven year archive of data is used to examine changes in the calibration of the AVHRR instruments carried on board the NOAA-5, -7, -8, -9 and -10 satellites. These changes are assessed from the point of view of using AVHRR data for climatological studies. Visible channels have no on-board calibration and the reported degradation of these channels suggests that visible data should only be used with great caution in climatological studies. Variations in infrared channel calibration are in the main associated with temperature changes on board the satellites. The on-board calibration procedures appear to cope adequately with these temperature changes.