Peter Schlüssel

The effective isotropic radiated power (EIRP) is a crucial parameter characterizing the transmitting antennas of a radio frequency satellite link. During the satellite commissioning phase, the requirements compliance of communication subsystems is tested. One of the required tests concerns the EIRP of the satellite transmitting antenna. Ground-based power measurements of the satellite-emitted signal are collected to measure EIRP, provided that an estimate of the atmospheric losses is available from independent ancillary measurements or model data. This article demonstrates the applicability of the so-called Langley method to infer EIRP and atmospheric attenuation simultaneously from ground-based power measurements, with no need for ancillary measurements. It is shown that the proposed method gives results similar to more traditional methods, without prior information on atmospheric attenuation. Thus, the proposed method can be applied to monitor EIRP throughout the satellite lifetime from ground-based power measurements alone.

The EUMETSAT Polar System – Second Generation (EPS-SG) is under development to follow the first generation EPS from 2022 onwards. EPS-SG will provide 9 observation missions in a dual satellite system in support of operational meteorology, climate monitoring and environmental services covering the ocean, atmosphere, land, cryosphere, and biosphere, to the extent they interact with, drive, or are driven by meteorology and climate. The benefits of EPS-SG for the Arctic and Northern regions cover a wide range of monitoring and user applications.

This paper present the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) polar orbiting satellite programmes. EUMETSAT operates today two polar orbiting satellites of the EUMETSAT Polar System in the so-called morning orbit with an equatorial descending crossing-time of 09:30 UTC. They constitute the European contribution to the Joint Polar System (JPS). The two satellites, denoted Metop-A and -B are part of the three satellite EUMETSAT Polar System (EPS). The third satellite of this first generation polar satellite series will be launched towards the end of 2018. In parallel EUMETSAT is preparing for its EPS Second Generation (SG) constellation. This is a twin-satellite system with three satellites each. The Metop-SG A-satellites form the imaging platform with the optical imaging, infrared and microwave sounding, aerosol imaging and radio occultation missions. It also hosts the Copernicus Sentinel-5 mission. The Metop-SG B-satellites are dedicated to microwave and submillimeter-wave imaging, scatterometry and radio occultation. It also hosts the ARGOS data collection system. This paper gives and overview of these two EUMETSAT programmes.

A review of remote sensing technology for lower tropospheric thermodynamic (TD) profiling is presented with focus on high accuracy and high temporal‐vertical resolution. The contributions of these instruments to the understanding of the Earth system are assessed with respect to radiative transfer, land surface‐atmosphere feedback, convection initiation, and data assimilation. We demonstrate that for progress in weather and climate research, TD profilers are essential. These observational systems must resolve gradients of humidity and temperature in the stable or unstable atmospheric surface layer close to the ground, in the mixed layer, in the interfacial layer—usually characterized by an inversion—and the lower troposphere. A thorough analysis of the current observing systems is performed revealing significant gaps that must be addressed to fulfill existing needs. We analyze whether current and future passive and active remote sensing systems can close these gaps. A methodological analysis and demonstration of measurement capabilities with respect to bias and precision is executed both for passive and active remote sensing including passive infrared and microwave spectroscopy, the global navigation satellite system, as well as water vapor and temperature Raman lidar and water vapor differential absorption lidar. Whereas passive remote sensing systems are already mature with respect to operational applications, active remote sensing systems require further engineering to become operational in networks. However, active remote sensing systems provide a smaller bias as well as higher temporal and vertical resolutions. For a suitable mesoscale network design, TD profiler system developments should be intensified and dedicated observing system simulation experiments should be performed.

The EUMETSAT Polar System (EPS) will be followed by a second generation system, EPS-SG, in the 2020-2040 timeframe and contribute to the Joint Polar System being jointly set up with NOAA. Among the various missions which are part of EPS-SG, there are the Microwave Imager (MWI) and the Ice Cloud Imager (ICI). The MWI frequencies are from 18 GHz up to 183 GHz. All MWI channels up to 89 GHz measure both V and H polarisations. The primary objective of the MWI mission is to support Numerical Weather Prediction at regional and global scales. The MWI will not only provide continuity of measurements for some heritage microwave imager channels (e.g. SSM/I, AMSR-E) but will also include additional channels such as the 50-55 / 118 GHz bands. The combined use of these channels will provide more information on cloud and precipitation over sea and land. The ICI will provide measurements over the sub-millimetre spectral range contributing to an innovative characterisation of clouds over the whole globe. The ICI has channels at 183 GHz, 325 GHz and 448 GHz with single V polarisation and two channels at 243 GHz and 664 GHz with both V and H polarisation. The ICI’s primary objectives are to support climate monitoring and validation of ice cloud models and the parameterisation of ice clouds in weather and climate models through the provision of ice cloud products.