Kourou – The “eye“ of the joint European Space Agency/EUMETSAT Meteosat Second Generation (MSG) satellite, the Seviri (Spinning Enhanced Visible and Infrared Imager) instrument, , will provide weather data of unprecedented precision to European meteorologists. Seviri is the latest in a long line of state-of-the-art meteorological instruments developed and built by Astrium, Europe’s leading space company. Following postponement of the launch last night, the spacecraft is now due for launch from Kourou, French Guiana, at about 22:30 tonight, Wednesday 28th August 2002.
For 25 years, the images of European Meteosat weather satellites have been broadcast daily in the television news of many countries. From 1977 to 1997, a total of seven European weather satellites were launched into geostationary orbit, all with Astrium technology on board.
Every 15 minutes, Seviri will transmit a satellite image to Earth – twice as often as the previous model on board the first Meteosat generation. Furthermore, the images from the new instrument will be more detailed: On the one hand, Seviri has a considerably enhanced resolution of 1km compared to its predecessor and, on the other, the instrument scans the Earth in twelve – instead of three – spectral channels. These twelve different channels, in the Infrared and Visible spectrum, allow comprehensive observation of various parameters, such as the temperatures of clouds, land and sea surfaces, as well as the composition of air masses in the atmosphere. “Nowcasting“, the short-term weather forecast, will primarily benefit from these new capabilities. Thus, in the near future, more precise forecasting of extreme and dangerous weather phenomena, such as thunderstorms or heavy rainfall will be possible.
This year, other Astrium-built instruments, AMSU-B and HSB were launched on board U.S. weather satellites. AMSU-B, the Advanced Microwave Sounding Unit, was launched on June 24 on board NOAA-M. This instrument mainly provides images of cloud cover and precipitation cells for short-term weather forecasts, as well as information on water vapour in cloudy areas, which is needed for medium-term forecast models.
Since May 4, the Humidity Sounder for Brazil (HSB) has been orbiting the Earth on board NASA’s Aqua spacecraft. This instrument measures the vertical distribution of water vapour in the atmosphere, a parameter having a direct influence on atmospheric stability.
The success story of Astrium-built meteorological instruments will continue on into the future: Two further satellites of the MSG fleet, both equipped with Seviri instruments, will also provide highly detailed weather data from geostationary orbit. As of 2005, Europe will also have its own system of polar- orbiting weather satellites. These satellites, under the name of Metop, will measure meteorological parameters with high precision at low altitude. In particular, medium and long-term weather forecasts and climate research will benefit from the Metop data. The three identical Metop satellites, due for launch at five-year intervals, will carry Astrium-built measuring instruments Ascat and MHS .
The Advanced Scatterometer (Ascat) is a radar instrument which measures the speed and direction of wind over the open sea. Ascat will also help to monitor the distribution of snow and ice on land and on sea surfaces.
The Microwave Humidity Sounder (MHS) is a microwave sensor for measuring the atmospheric humidity profiles, cloud and precipitation parameters.
By 2007, one of the last gaps in global weather and climate research will be filled by ESA’s Aeolus spacecraft. In July of this year, ESA, as the prime contractor, approved the Aeolus mission with Astrium as the proposed contractor for the initial programme. The Aladin (Atmospheric Laser Doppler Instrument) instrument on board Aeolus will measure wind strengths and directions with unprecedented precision y sending short harmless laser pulses into the atmosphere and analysing the laser light returned by the atmospheric cells.
