SCIAMACHY: New Level 0-1 Processor and Plans for the Future

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 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. The operational processing of SCIAMACHY aims to deliver continuously high quality data products to the scientific community. It is split into Level 0-1 processing (essentially providing calibrated radiances) and Level 1-2 processing providing geophysical products. The operational Level 0-1 processor has been completely re-coded and embedded in a newly developed framework that speeds up processing considerably. A better degradation correction was implemented that now takes into account the dependence of transmission on the incidence angle of light on the mirror. The stray light correction now uses a matrix correction scheme for all channels. The handling of calibration data was completely overhauled: instead of using a collection of files we use a database that allows proper traceability of used calibration data for any given Earth measurement and that allows immediate quality checks. With the improved Level 1 products it is expected that the Level 2 products are also improved (see related contribution on operational Level 2 products from SCIAMACHY). Both datasets were re-processed. Here we will report on the quality of the Level 1 data. In addition future planned improvements such as a new bad pixel mask in the SWIR channel will be discussed.