EUMETSAT Polar System–Second Generation: Continuation of Observations and Advancing Applications from Low-Earth Orbit

Abstract EUMETSAT successfully launched the first satellite of the EUMETSAT Polar System–Second Generation (EPS-SG), developed as a collaborative program between EUMETSAT and ESA, on 13 August 2025 at 0037:50 (UTC) on an Ariane 62 launcher. EPS-SG is Europe’s contribution to the NOAA–EUMETSAT Joint Polar System, continuing and expanding midmorning orbit observations provided by the Metop satellites. EPS-SG comprises three satellites collecting optical imaging and sounding observations (Metop-SGA) and three satellites collecting active and passive microwave observations (Metop-SGB) deployed in pairs, each satellite with a 7.5-yr design lifetime, including 6 months for commissioning. In addition to providing improved legacy observations with the Infrared Atmospheric Sounding Interferometer–New Generation (IASI-NG), Meteorological Imager (METimage), Microwave Sounder (MWS), and Radio Occultation (RO) instruments, the Metop-SGA satellites will carry the Multi-viewing Multi-channel Multi-polarisation Imager (3MI), a passive polarimeter for monitoring atmospheric aerosol and clouds, and the Copernicus Sentinel-5 Ultraviolet (UV)/Visible (Vis)/Near-infrared (NIR)/Shortwave infrared (SWIR) (UVNS) sounding instrument, provided by ESA and the European Commission, measuring trace gases and aerosols. The Metop-SGB satellites will continue observations of ocean vector wind fields with the scatterometer (SCA), also host an RO instrument, and carry the Microwave Imager (MWI) for monitoring precipitation, temperature, clouds, water vapor, sea ice, and snow cover. Metop-SGB will also provide novel observations with the Ice Cloud Imager (ICI), covering submillimeter wavelengths for global observations of ice clouds. Finally, Metop-SGB will in addition carry the Advanced Data Collection System, Argos-4, contributing to the Argos worldwide location and data collection system. This paper describes these instruments, outlines the related products and services, and addresses the evolution of further applications. Significance Statement The EUMETSAT Polar System–Second Generation (EPS-SG) is a key element of the World Meteorological Organization’s Integrated Global Observing System and the EUMETSAT–NOAA Joint Polar System. This paper provides the readers with detailed information on the EPS-SG system and its capabilities, enabling the user community to prepare for the new system. Furthermore, it provides the readers with valuable detailed information and references to be able to exploit the new capabilities across a wide range of key application areas. As such, the paper is critical for the wider meteorological and Earth observation user communities and presents a reference baseline for publications based on the exploitation of the data from EPS-SG.