VALIDATION OF MIPAS-ENVISAT VERSION 4.61 OPERATIONAL DATA: NO_2

摘要

Embedded in the ENVISAT validation programme ofrnthe chemistry instruments GOMOS, MIPAS, andrnSCIAMACHY a large number of balloon-borne,rnaircraft and ground-based measurements werernsuccessfully carried out in the years 2002 and 2003 inrnthe Arctic and at mid-latitudes. Unfortunately, reanalyzedrnoperational MIPAS data were only availablernfor the year 2002 limiting the number of validationrnmatches with the new version 4.61 data significantly.rnApart from retrieval instabilities in the operationalrnMIPAS profiles balloon-borne observations are in goodrnagreement with the MIPAS satellite measurements.rnThe same holds also for a satellite inter-comparisonrnwith HALOE (version 19) data. Compared to POAMrnIII, MIPAS exhibits a low bias of about 20% in thernmiddle and lower stratosphere. While aircraftrnmeasurements are not quantitatively rateable due tornnon-overlapping measurement altitudes, ground-basedrninter-comparisons show a high bias in the measuredrnMIPAS partial columns compared to FTIRrnobservations in Kiruna and, in contrary, a low biasrncompared to UV-vis measurements in Harestua.rnFurther validation coincidences have to be consideredrnbefore a final quantitative assessment on the quality ofrnthe MIPAS operational NO_2 data is possible. Potentialrnmismatches between two different sensors in terms ofrntime and space need to be corrected with the help ofrnphotochemical model calculations taking into accountrnthe diurnal variation of the target species NO_2.