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Presentation given at the19th GHRSST science meeting (XIX), Darmstadt, Germany, June 4- 8, 2018.

[ABSTRACT]The paper provides an overview of the meteorological satellite systems operated by EUMETSA T: The first generation of European geostationary Meteosat satellites started with the launch ofMeteosat-1 in 1977 under the responsibility of ESA (European Space Agency). A series of seven satellites provided a continuous service acquiring half-hourly images in three spectral bands. Meteosat-7 is now still used for observing the Indian Ocean area. The advent of the first Meteosat Second Generation (MSG) satellite in 2002, renamed to Meteosat-8 with the start of operations, marked a major step forward in terms of observing capability. MSG satellites take images in twelve spectral channels every 15 minutes. The operational products derived from MSG data provide essential information for numerical weather prediction (NWP) and N owcasting. The MSG system is now a dual satellite system with Meteosat-9 as prime satellite and Meteosat-8 providing rapid imaging services. Two more MSG satellites will be launched before the next generation (Meteosat Third Generation: MTG). The first polar orbiting meteorological satellite of EUMETSAT, named Metop-A, was launched in October 2006. Metop provides advanced observations of temperature and humidity profiles, wind, ozone and trace gases. The instrumentation is based on a continuity of known instruments and novel techniques. Notable are the hyperspectral thermal infrared observations with IASI (Infrared Atmospheric Sounding Interferometer) which also plays a key role for the observation of climate parameters and as reference instrument for satellite intercalibration . Two more Metop satellites are scheduled for launch.

Geophysical parameters from the IASI instrument on Metop-A are essential products provided from EUMETSAT's Central Facility in near real time. They include vertical profiles of temperature and humidity, related cloud information, surface emissivity and temperature, and atmospheric composition parameters (CO, ozone and several other trace gases). The IASI L2 processor version 5 has been running routinely since September 2010. We give here a short summary of the most recent related validation studies, including results from the Metop-B/IASI L2 Cal/Val activities which started end January 2013, after the conclusion of the first phase of the L1c commissioning. We then introduce the current developments and the future evolutions of the IASI L2 processor operated at EUMETSAT towards the version 6 (v6), which release is scheduled second half of 2013. In particular we will address the integration of new atmospheric composition products from ULB/LATMOS in the scope of O3M-SAF CDOP-2, with first the retrieval of CO profiles. Only the CO total column has been retrieved until version 5. The cloud screening has been improved with the addition of a third detection algorithm based on artificial neural networks and independent from NWP forecasts. We will discuss here the use of concurrent cloud detection methods and the relationship between the cloudiness estimate and the sensing products yield and quality. A quality indicator is associated to the retrieved geophysical parameters in v6. Lastly, new retrieval methods for temperature and water-vapour sounding have been developed, including joint use of micro-wave (MW) and infrared (IR) measurements. The statistical MW+IR retrieval scheme, developed for v6, takes advantage of AMSU and MHS measurements collocated with IASI L1c spectra. It allows for sounding below the clouds in most cloud contaminated IFOVs with improved performances (typically about 1K rms) as compared to the current operational IR-based partly-cloudy retrieval. The MWIR-derived temperature and humidity profiles are used to constrain the retrieval of temperature, humidity and ozone 1D-Var retrievals in clear sky. The latter are performed with reconstructed radiances from a new channel selection and a scene-dependent bias correction. Initial results with the version 6 using ECMWF analyses as reference have shown that the temperature profiles are improved by 0.2 to 0.5K rms in the lower troposphere and that the precision in water-vapour profiles is increased by 30 to 50% in the boundary layer.

The Infrared Atmospheric Sounding Interferometer (IASI) forms the main infrared sounding component of the European Organisation for the Exploitation of Meteorological Satellites's (EUMETSAT's) Meteorological Operation (MetOp)-A satellite (Klaes et al. 2007), which was launched in October 2006. This article presents the results of the first 4 yr of the operational IASI mission. The performance of the instrument is shown to be exceptional in terms of calibration and stability. The quality of the data has allowed the rapid use of the observations in operational numerical weather prediction (NWP) and the development of new products for atmospheric chemistry and climate studies, some of which were unexpected before launch. The assimilation of IASI observations in NWP models provides a significant forecast impact; in most cases the impact has been shown to be at least as large as for any previous instrument. In atmospheric chemistry, global distributions of gases, such as ozone and carbon monoxide, can be produced in near–real time, and short-lived species, such as ammonia or methanol, can be mapped, allowing the identification of new sources. The data have also shown the ability to track the location and chemistry of gaseous plumes and particles associated with volcanic eruptions and fires, providing valuable data for air quality monitoring and aircraft safety. IASI also contributes to the establishment of robust long-term data records of several essential climate variables. The suite of products being developed from IASI continues to expand as the data are investigated, and further impacts are expected from increased use of the data in NWP and climate studies in the coming years. The instrument has set a high standard for future operational hyperspectral infrared sounders and has demonstrated that such instruments have a vital role in the global observing system.