SCIAMACHY: Impact of calibration changes on SCIAMACHY CO retrievals

Abstract

SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) was a scanning nadir and limb spectrometer covering the wavelength range from 212 nm to 2386 nm in 8 channels. It is a joint project of Germany, the Netherlands and Belgium and was launched in February 2002 on the ESA's ENVISAT platform. After the platform failure in April 2012, the space Agencies continue to support the operational product evolution in the frame of the SCIAMACHY Quality Working Group and Expert Support Laboratory.. Note that SCIAMACHYs originally specified in-orbit lifetime was twice the planned lifetime. The instrument was designed to measure column densities and vertical profiles of trace gas species in the troposphere, in the stratosphere and in the mesosphere (Bovensmann et al., 1999). It can detect a wide range of trace gases and can provide information about aerosols and clouds. For the next Level 1 processor several improvements that concern the SWIR products CH4 and CO are planned like a better dark correction, an improved spectral calibration and a better bad pixel mask. Using the BIRRA (the Beer InfraRed Retrieval Algorithm)retrieval scheme which is also the basis of the operational processing, we will analyse the impact of the various Level 1 improvements on the CH4 and CO products. The results of this sensitivity study will be shown in this contribution.