On the geometric accuracy and stability of MSG SEVIRI images

Abstract

Monitoring the geometric quality and temporal stability of Earth Observation satellite sensors is a major task of satellite vendors. As an owner and operator of widely used meteorological satellites, EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) carries out operational activities and scientific studies on the radiometric and geometric quality assessments of geostationary Meteosat satellites among others. As part of Level 1 Product Monitoring - Evolution Studies initiated by EUMETSAT, a new methodology has been developed and implemented as a prototype software, namely the Geometric Quality Assessment (GQA) Tool; which enhances image local texture, extracts prominent features and matches them via area-based least squares, and eliminates possible outliers using a set of rules. This article presents the results of algorithm validation activities carried out by using time series images of the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensor aboard Meteosat Second Generation (MSG) satellites and MEdium Resolution Imaging Spectrometer (MERIS) global mosaics as reference to evaluate short- and long-term geometric temporal stability. Meteosat-11 SEVIRI time series data from a full-day and one year were employed for this purpose. In addition, the geometric quality of Meteosat-8 over Indian Ocean and Meteosat-10 in rapid scan mode was assessed for single acquisitions. The results show that the geometric accuracy of the evaluated datasets yield to the mean shifts up to one km in East-West (x) and North-South (y) directions, with larger errors in the y direction. The image inner geometric accuracy assessments revealed displacement errors with strip pattern in the three spectral bands (i.e. high-resolution visible, infra-red 10.8 and visible 0.8) evaluated within the framework.