Observation requirements for the second generation EUMETSAT polar system visible/infrared imager

Abstract

The EUMETSAT Polar System Second Generation (EPS-SG) will continue operational meteorological measurements from polar orbiting satellites in the mid-morning orbit in the 2020 timeframe. The Metop Second Generation (Metop- SG) satellites will carry a payload which is primarily dedicated to operational meteorology and climate monitoring. A core mission within this payload is an optical imager required to meet the imagery user needs for Numerical Weather Prediction (NWP), Nowcasting (NWC) and climate applications. As NWP progresses towards operation on higher spatial resolution grids, improved representation of atmospheric processes encompassing the whole Earth system will be required, hence the availability of observations of clouds and aerosols as well as surface parameters will play an increasing role in a skilful weather forecast. Imagery data will also be very important in NWC applications, particularly in polar regions where space-borne imagery from geostationary satellites is not available. The EPS-SG Visible/Infrared Imaging mission (VII) follows on from an important list of predecessors such as the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate resolution Imaging Spectro-radiometer (MODIS). The VII mission is planned to be implemented by the METimage instrument, developed by Deutsches Zentrum für Luft und Raumfahrt (DLR). METimage is a cross-purpose medium resolution, multi-spectral optical imager, measuring the optical spectrum of radiation emitted and reflected by the Earth from a low-altitude sun synchronous orbit over a minimum swath width of 2800 km. The spectral and radiometric performances and space-time resolution introduce novel observing capabilities that will enhance the observation potential compared to current operational optical imagers. These enhanced capabilities along with the evolution of the VII observation requirements are discussed.