Total and tropospheric ozone columns from Sentinel-5P

Kurzfassung

In October 2017, the Sentinel-5P satellite with the TROPOMI instrument was launched into space. Total ozone columns from TROPOMI instrument are retrieved in near real time using the well established DOAS approach, and a subsequent conversion into vertical column densities using an iterative air mass factor calculation. The total ozone algorithm has already been successfully applied to the GOME, SCIAMACHY and GOME-2 missions. To account for the high spatial resolution of the TROPOMI instrument, the treatment of clouds in the total ozone retrieval has been improved. Besides the total column, a tropospheric ozone column is also provided from TROPOMI. The cloud convective differential method is used to separate the tropospheric and stratospheric ozone column. Deep convective clouds shield the tropospheric ozone from the satellite based observers. Therefore the ozone columns above deep convective clouds are good approximations of the stratospheric ozone column. These data are corrected for the variety in the cloud top altitudes and averaged over a 5 days time period and a clean area. In a last step the stratospheric column are subtracted from the total ozone columns for cloud free observations. After a short introduction to the retrieval algorithms, first results will be presented for both total and tropospheric ozone columns from TROPOMI. First comparisons to ozone column data from GOME-2 and ground-based observations will be shown as well.