The principle objective of the GERB (Geostationary Earth Radiation Budget) mission is to measure the Earth radiation budget, in support of climate research and monitoring. A GERB International Science Team (GIST) had been established and tasked inter alia to define the science requirements, products and processing algorithms, and to implement science and validation activities. The consortium that developed and is responsible for operating the GERB system includes the Rutherford Appleton Laboratory (RAL), UK; Imperial College of Science, Technology and Medicine (ICSTM), UK; Hadley Centre, UK; Leicester University, UK; RMI, Belgium; Advanced Mechanical and Optical Systems Ltd (AMOS Ltd), Belgium; and Officine Galileo, Italy.

The GERB instrument is a scanning radiometer with two broadband channels, one covering the solar spectrum (0.32 to 4.0 µm), the other covering a wider portion of the electromagnetic spectrum (0.32 to 30 µm).  Together these channels are used to derive the thermal radiation emitted by the Earth in the spectral range 4.0 to 30 µm. Data are calibrated on board in order to support the retrieval of radiative fluxes of reflected solar radiation and emitted thermal radiation at the top of the atmosphere with an accuracy of 1%. The radiation budget represents the balance between incoming energy from the Sun and outgoing thermal (longwave) and reflected (shortwave) energy from the Earth.

The GERB broadband channels span the twelve much narrower channels measured by the MSG's other instrument – the Spinning Enhanced Visible and Infrared Imager (SEVIRI). Thus GERB fills in the gaps in the thermal radiation spectrum missed by the SEVIRI channels. However, the GERB measures the thermal radiation at a coarser spatial resolution. Back on the ground, RMI scientists use the finer spatial resolution of the SEVIRI data to improve the spatial resolution of the GERB images.


Status: Operational
Satellite MeteoSat-9
Launch Date: December 2005
Type: Earth radiation budget radiometers
Measurements and Applications: Measures long and short wave radiation emitted and reflected from the Earth's surface, clouds and top of atmosphere. Full Earth disk, all channels in 5 mins

Technical Characteristics

Resolution: 44 km
N. of Bands: -
Wavebands: SW : 0.32 - 4.0 µm
LW : 4.0 - 30 µm 
Swath: Full Earth Disk




GERB Web Page