The Global Ozone Monitoring Instrument (GOME‐2) was launched on EUMESAT's MetOp‐A satellite in October 2006. This paper is concerned with the retrieval algorithm GOME Data Processor (GDP) version 4.4 used by the EUMETSAT Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M‐SAF) for the operational generation of GOME‐2 total ozone products. GDP 4.4 is the latest version of the GDP 4.0 algorithm, which is employed for the generation of official Level 2 total ozone and other trace gas products from GOME and SCIAMACHY. Here we focus on enhancements introduced in GDP 4.4: improved cloud retrieval algorithms including detection of Sun glint effects, a correction for intracloud ozone, better treatment of snow and ice conditions, accurate radiative transfer modeling for large viewing angles, and elimination of scan angle dependencies inherited from Level 1 radiances. Furthermore, the first global validation results for 3 years (2007–2009) of GOME‐2/MetOp‐A total ozone measurements using Brewer and Dobson measurements as references are presented. The GOME‐2/MetOp‐A total ozone data obtained with GDP 4.4 slightly underestimates ground‐based ozone by about 0.5% to 1% over the middle latitudes of the Northern Hemisphere and slightly overestimates by around 0.5% over the middle latitudes in the Southern Hemisphere. Over high latitudes in the Northern Hemisphere, GOME‐2 total ozone has almost no offset relative to Dobson readings, while over high latitudes in the Southern Hemisphere GOME‐2 exhibits a small negative bias below 1%. For tropical latitudes, GOME‐2 measures on average lower ozone by 0% to 2% compared to Dobson measurements.

Abstract. The three Global Ozone Monitoring Experiment-2 instruments will provide unique and long data sets for atmospheric research and applications. The complete time period will be 2007-2022, including the period of ozone depletion as well as the beginning of ozone layer recovery. Besides ozone chemistry, the GOME-2 (Global Ozone Monitoring Experiment-2) products are important e.g. for air quality studies, climate modelling, policy monitoring and hazard warnings. The heritage for GOME-2 is in the ERS/GOME and Envisat/SCIAMACHY instruments. The current Level 2 (L2) data cover a wide range of products such as ozone and minor trace gas columns (NO 2 , BrO, HCHO, H 2 O, SO 2 ), vertical ozone profiles in high and low spatial resolution, absorbing aerosol indices, surface Lambertian-equivalent reflectivity database, clear-sky and cloud-corrected UV indices and surface UV fields with different weightings and photolysis rates. The Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) processes and disseminates data 24/7. Data quality is guaranteed by the detailed review processes for the algorithms, validation of the products as well as by a continuous quality monitoring of the products and processing. This paper provides an overview of the O3M SAF project background, current status and future plans for the utilisation of the GOME-2 data. An important focus is the provision of summaries of the GOME-2 products including product principles and validation examples together with sample images. Furthermore, this paper collects references to the detailed product algorithm and validation papers.

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T he German Satellite Data Archive (D-SDA) at the German Aerospace Center (DLR) has been managing largevolume Earth-observation (EO) data in the context of EOmission payload ground segments (PGSs) for more than two decades. Hardware, data management, processing, user access, long-term preservation, and data exploitation ex-pertise are under one roof and interact closely. Upcoming EO-mission PGSs benefit as much from the comprehensive expertise, close interaction, and integrated infrastructure as do in-house scientific application projects requiring access, processing, and archiving of large-volume EO data. Using a number of examples, we will demonstrate how EO data life cycles benefit from the proximity of data management and application scientists and from the extensive operational experience gathered over time.

This paper describes the motivation, requirements, and challenges of integrating a geospatial infrastructure, based on standardized web services, into an earth observation (EO) data library. The design of harmonized data and information models of the EO and geospatial community is a precondition for interoperability at metadata, data and semantic levels. A major challenge arises from raising the awareness that interoperability is essential for an interdisciplinary use of EO data in Geographic Information System (GIS) and value-adding services.