Jochen Skupin

SCIAMACHY on ENVISAT: in-flight optical performance and first results

The Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) is a contribution to the ENVISAT-1 satellite, which has been launched in March 2002. The SCIAMACHY instrument measures sunlight transmitted, reflected and scattered by the Earths atmosphere or surface simultaneously from the UV to the SWIR spectral region (214 - 2380 nm) in nadir, limb, and occultation viewing geometry. SCIAMACHY allows the characterisation of the composition of the Earth atmosphere from the ground to the mesosphere. This paper gives an overview of the SCIAMACHY instrument and its in-flight detector, spectral and radiometric performance. Furthermore first results on trace gas retrieval from limb and nadir measurement mode will be summarised.

The SCIAMACHY Calibration/Monitoring Concept and First Results

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) is a contribution to the ENVISAT satellite, which has been launched successfully in March 2002. SCIAMACHY determines the amount and distributions of a large number of atmospheric constituents by measuring Earthshine radiance and solar irradiance spectra simultaneously from the UV to the NIR in various viewing geometries. The scientific goals of the SCIAMACHY mission can only be reached by an instrument having a high spectral and radiometric accuracy and stability. For example, to determine global NO2 concentrations SCIAMACHY measurements need to be sensitive to differential spectral structures down to the order of 10−4. These requirements can only be met by an appropriate instrument design in combination with both on-ground and in-flight calibration and monitoring. This paper gives an overview on the SCIAMACHY calibration and monitoring concept and activities which are essential to ensure the high quality of SCIAMACHY data products throughout the instrument lifetime. Furthermore, first in-flight monitoring results are presented.

In-flight calibration of the SCIAMACHY solar irradiance spectrum

Abstract ESAs new Earth observation satellite ENVISAT was launched successfully on 2002-02-28. Among nine other instruments it is carrying the new imaging spectrometer SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography). This paper covers part of the calibration and validation efforts during the first seven months of SCIAMACHY in orbit with special emphasis on the application of the internal white light source for radiometric calibration. The solar irradiance spectrum measured by SCIAMACHY is presented and compared with a solar spectrum derived by R. L. Kurucz as well as with solar irradiances measured by the UARS instruments SOLSTICE and SUSIM.

The SCIAMACHY instrument on ENVISAT: first performance monitoring results

Since March 2002 the spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is orbiting the Earth aboard the new European environmental satellite ENVISAT. SCIAMACHY will measure during the next years concentrations and distributions of atmospheric trace gases (O/sub 3/, BrO, OClO, ClO, SO/sub 2/, H/sub 2/CO, NO/sub 2/, CO, CO/sub 2/, CH/sub 4/, H/sub 2/O, N/sub 2/O), clouds, and aerosols. To assure the quality of these data products at any time during the whole mission a detailed knowledge of the instruments status and behavior is mandatory. To achieve this a comprehensive monitoring concept has been developed and implemented. This paper presents selected results of performance monitoring activities from the commissioning phase and from early nominal operations of the instrument, showing that SCIAMACHY is in good shape.

SCIAMACHY on ENVISAT: instrument monitoring and calibration two years after launch

Since 2002-03-01 the spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is in a sun-synchronous polar orbit around the Earth aboard the new European environmental satellite ENVISAT. SCIAMACHY measures during its lifetime concentrations and distributions of atmospheric trace gases such as O3, BrO, OClO, ClO, SO2, H2CO, NO2, CO, CO2, CH4, H2O, N2O, metals, clouds, and aerosols. The quality of these data products depends both on the calibration of the instrument and the detailed knowledge of the instruments status and behaviour at any time during the whole mission. To achieve this a comprehensive monitoring concept has been developed and implemented. This paper gives a brief overview of the instrument and the calibration and monitoring concepts. Results of the performance monitoring activities from nominal operations of the instrument show that SCIAMACHY in general is in good shape. The radiometric calibration of the instrument could be enhanced by a thorough revision of the on-ground calibration. An ice-layer buildup is observed on the IR detectors, which shall be compensated by a throughput correction factor.