TOTAL O{sub}3 COLUMNS FROM SCIAMACHY OL3.0 TO SCIAMACHY WEIGHTING FUNCTION DOAS (WFDOAS), OMI-TOMS AND GOME WFDOAS

摘要

Global stratospheric ozone columns from satellite instrument SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) on ENVISAT derived from the newest operational data product OL3.0 are compared to data products of the SCIAMACHY Weighting Function DOAS Algorithm (WFD), GOME WFD and OMI TOMS algorithm. The comparisons are also analysed for dependencies to total ozone, solar zenith angle and latitude. Due to the limited data set of SCIAMACHY OL3.0 with only 5 nearly complete days and 4 days with 4 orbits each the validation results are quite preliminary. There is an indication that OL3.0 data products show a major improvement compared to previous operational data versions with an agreement within 1% (RMS < 2.5%) to GOME WFD and OMI TOMS. No clear dependencies to total ozone and latitude are observed. In two cases there might be a dependency to SZA, which should be investigated further with a larger data set. The comparisons to SCIA WFD V2 showed the negative bias of 1-2% with SCIA OL3.0, which has been previously described in comparisons to GOME WFD and OMI TOMS and has been interpreted as a calibration error in SCIA lv-1, which has been accounted for in the OL3.0 processing. Despite this offset, SCIA WFD shows no dependencies to SZA, latitude and total ozone. Results help to understand how these different global total ozone data sets can be linked together for ozone trend studies.