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Inter-comparison on the influence of different cloud parameter algorithms for the derivation of O3 and NO2 vertical column densities from SCIAMACHY nadir back-scattered observations

Thomas Schroeder(1), Albrecht von Bargen(2), Christophe Lerot(3), Michel Van Roozendael(3), Mark Weber(4), Lok Lamsal(4) and Heinrich Bovensmann(4)

(1) German Aerospace Center, PO Box 1116, 82234 Wessling, Germany
(2) German Aerospace Center, 82234 Wessling, PO Box 1116, Germany
(3) Belgian Institute for Space Aeronomy, Avenue Circulaire 3, 1180 Brussels, Belgium
(4) University of Bremen, PO Box 330440, 28334 Bremen, Germany

Abstract

The operational data processors for the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) onboard ESA’s ENVISAT were recently subject to a major upgrade in its retrieval to several products. One focus was dedicated to the integration of the SCIAMACHY DOAS (SDOAS) algorithm from BIRA-IASB for the derivation of Ozone and NO2 vertical column densities from nadir back-scattered light observations. In deviation to the original approach, cloud parameter are provided by the newly integrated SACURA algorithm of IFE Bremen for cloud-top height and cloud optical thickness and the OCRA algorithm of DLR-IMF for cloud coverage. This is also in alternative to the operational implementation (GDP 4.0) selected for processing of GOME back-scattered light observations where the column densities are derived with the GOME DOAS (GDOAS) algorithm of BIRA-IASB in combination with the cloud algorithms OCRA and ROCINN of DLR-IMF. SACURA was selected because it provides additional cloud parameters. Thus, this presentation is dedicated to the effect of different cloud algorithms on the trace gas retrievals. For this, the operational SDOAS implementation at DLR-IMF in combination with SACURA and OCRA will be compared with the original SDOAS implementation based on the combination with the FRESCO algorithm developed at KNMI. Additionally FRESCO data are fed into the operational processor for cross-check. The study is completed by results of Weighting-function DOAS (WF-DOAS) of IFE-Bremen that use both OCRA/SACURA and FRESCO.

 

Workshop poster

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry