Formaldehyde and Glyoxal: New Products in the SCIAMACHY Operational Processor

In sommer of 2010 version 6 of the SCIAMACHY operational processor is planned to be delivered to ESA. The SCIAMACHY Quality Working Group recommended an implementation of the formaldehyde (HCHO) and glyoxal (CHOCHO) vertical columns into version 6 of the off-line processor. They are formed during the oxidation of volatile organic compounds (VOCs) emitted by plants, anthropogenic activities, and biomass burning. Due to a rather short lifetime of formaldehyde and glyoxal, their distribution maps, obtained by the SCIAMACHY, represent the emission fields of their precursors, VOCs. The descriptions of reference algorithm as well as all the cross-sections for formaldehyde and glyoxal retrievals were delivered to DLR by the Belgian Institute for Space Aeronomy (BIRA) (I. De Smedt, 2008) and by the IUP (F. Wittrock, 2006), respectively. Both retrievals are based on the DOAS technique. For the formaldehyde retrieval the spectral region of 328.5-346 nm was recommended. The absorption cross-sections of HCHO, O3, NO2, BrO, OClO, a Ring spectrum and a polynomial of the fifth order are included into the fitting procedure. Before conversion to the vertical columns, the slant columns have to be normalized by subtracting the slant columns measured over Pacific ocean, where the only source of formaldehyde is methane oxidation. After the conversion to the vertical columns, part of HCHO removed during the previous procedure has to be re-added to the final vertical column by adding of the mean vertical column calculated by the tropospheric chemistry model IMAGES (J.-F. Müller, 1995). This normalization is necessary to compensate for the offset introduced by the solar reference measurements and interferences by other absorbers. For the determination of glyoxal columns, the spectral region 435-457 nm was selected. In this case, the absorption cross-sections of CHOCHO, O3, NO2, H2O, O4, a Ring spectrum and a cubic polynomial are included in the fitting procedure. The normalization of the CHOCHO slant columns is performed in the same way as for formaldehyde

Development Of SCIAMACHY Operational ESA Level 2 Products Towards Version 5 And Beyond

Since the foundation of the SCIAMACHY Quality Working Group (SQWG) in a joint ESA-DLR-NIVR inter-agency effort in late 2006, the ESA operational Level 2 processor was significantly improved w.r.t. data quality and product range. During the last two years the product list was substantially enhanced by new (total columns of SO2, BrO, OClO, H2O, CO, Limb BrO profiles, Limb cloud flags) and improved products (total columns of O3, NO2, Absorbing Aerosol Index, Limb O3 profiles, Limb NO2 profiles). For example, important improvements were achieved in the O3 and NO2 profile calculation by implementing an upgraded retrieval scheme and using now Level 1b version 7.0 data with an improved pointing correction. Nadir products of total column O3 and Absorbing Aerosol Index were improved by applying a radiometric degradation correction (m-factors) in the Level 1 to 2 processing step

The Major Revisions of the Operational SCIAMACHY Level 1b-2 Off-line Data Processor

Der Konferenzbeitrag beschreibt den Update des operationellen SCIAMACHY Level 1b-2 Off-line Prozessors im Hinblick auf seine Algorithmen. Im Vordergrund stand die Integration des SDOAS Algorithmus von BIRA-IASB im Zusammenspiel mit WOlkenalgorithmen des DLR und der Universität Bremen. Darüber hinaus wurde die vollkommen neue Version des Profilretrievals aus Limb Messungen vorgestellt

SCIAMACHY Level 1b-2 Data Processing: Update of Off-line Data Processor to Version 3.0

Präsentation des Upgrades der Algorithmen zur operationellen Prozessierung von SCIAMACHY Messdate

Chapter 8: Processing and Products

SCIAMACHY data processing generates products on various levels as required by the user community. These products are either produced in the ENVISAT Payload Data Segment as operational products or by science institutes as scientific products or value-added products. Operational processing occurs in two steps – level 0-1b and level 1b-2. In both steps different timescales may apply – near-realtime, fast delivery or offline. Level 0-1b processing generates geolocated and calibrated radiances from the raw atmospheric measurements, as well as from measurements for calibration and instrument monitoring. The algorithms convert measured signals into calibrated radiances. Therefore a sequence of calibration steps has to be applied starting with correcting the memory effect and non-linearity and ending with applying the radiometric instrument response. Particular attention has to be given to the correction of polarisation and degradation. The goal of level 1b-2 processing is to provide geophysical parameters such as column densities and profiles from trace gas species as well as cloud and aerosol parameters. Nadir measurements permit retrieving total column densities or cloud and aerosol parameters. From limb observations height resolved profiles of atmospheric parameters can be inferred. Together with the scientific and value-added products the SCIAMACHY data can serve a wide range of applications

Nine Years of Atmospheric Remote Sensing with SCIAMACHY - Atmospheric Parameters and Data Products

The SCIAMACHY instrument on-board ENVISAT measures since 2002 trace gas constituents of the atmosphere in nadir, limb and occultation configuration. It is an imaging spectrometer with a spectral range from the UV/VIS to SWIR (212 nm – 2384nm). In this paper we describe shortly the current status of the operational processing chains from Level 0-1b and Level 1b-2 that deliver Earth radiances, solar irradiance, trace gas total columns and profiles as well as cloud characteristics on an orbital basis. An outlook for future operational products is also given

Development of SCIAMACHY Operational ESA Level 2 Version 6 Products

Since the establishment of the SCIAMACHY Quality Working Group (SQWG) in a joint inter-agency ESA-DLR-NSO effort in late 2006, the ESA operational Level 2 processor was significantly improved w.r.t. data quality and the product list was substantially enhanced with new parameters. Current operational Level 2 products correspond to version 5. Meanwhile the Quality Working Group has prepared the next product version 6. This paper summarises the key characteristics of the Level 2 version 5 and 6