BRIDGING THE GAP BETWEEN AATSR AND SLSTR OBSERVATIONS USING AVHRR AND IASI

摘要

There is a need to find a candidate instrument that canrnbridge the gap between AATSR and SLSTR climate qualityrnIR observations. Due to restrictions relating to the orbitrnof ENVISAT and Sentinel-3 only MODIS on TERRArnand AVHRR on MetOp-A could potentially provide observationsrnfor a period that will overlap significantly withrnSLSTR. Here, the use of AVHRR is explored due to itsrncollocation on the same platform with IASI, which is thernreference instrument for calibration studies in the infraredrnspectrum. Previous studies have examined the calibrationrnaccuracy of the two longwave AVHRR channels usingrnIASI, and so this study focuses mainly on the possiblerntemporal trends, including the SWIR channel at 3.7rnu0016m. There is a spatial correlation of the IASI-AVHRRrndifferences with the water vapour geographical distribution,rnwhile the high noise of the shortwave IASI channelsrnmakes the comparison at low temperatures (i.e. atrnhigh latitudes) problematic. Temporal trends are found inrnthe differences between IASI and AVHRR channels beingrnless or equal to 10 mK/yr.