The image service is the main mission of Meteosat Second Generation (MSG). The service provides High Rate SEVIRI image data, in 12 spectral bands from the satellite's field of view. The data are processed in near real-time to Level 1.5, i.e. corrected for radiometric and geometric non-linearity, before being distributed. Information that allows the user to calculate the geographical position and radiance of any pixel is also included. Before distribution to the user, the data are compressed using lossless compression in the form of Wavelet Transform.
A secondary Low Rate SEVIRI service is also provided, comprising of a subset of five SEVIRI spectral channels. Data are compressed using lossy JPEG compression.
The nominal coverage of the prime MSG service includes the whole of Europe, the Atlantic Ocean, all of Africa and at locations where the elevation to the satellite is greater than or equal to 10°.
The SEVIRI instrument allows for a complete image scan (Full Earth Scan) once every 15-minute period. Each 15-minute period, or repeat cycle, consists of eight segments of image data, except the HRV channel which has 24 segments. Each segment has 464 lines of image data. A repeat cycle prologue file precedes the delivery of the image segments and a repeat cycle epilogue file follows delivery and contains final quality information for the image. The image segments are numbered and a fixed relationship between the image segment number and the line offset is established. The image segment numbering direction follows the radiometer scan direction.
High Rate SEVIRI image data consist of geographical arrays of various sizes of image pixels. Each pixel contains 10 data bits, representing the received radiation from the earth and its atmosphere in the 12 spectral channels. Of these 12 spectral channels, 11 provide measurements with a resolution of 3 km at the sub-satellite point with the twelfth, the High Resolution Visible (HRV) channel, providing measurements with a resolution of 1 km:
Visible band centred on 0.6µm - Channel 1 (VIS 0.6)
The Low Rate SEVIRI services comprises the following five spectral channels:
The HRV channel supports Alternative HRV Scanning Mode Operations. In this mode it is possible to introduce a horizontal split into the HRV image, and separately specify the E-W offset of the HRV image window above and below the split. The HRV scanning mode is:
High Rate SEVIRI Image Product contains numerous image quality indicators. These indicators provide information on the completeness, geometric quality, radiometric quality, and timeliness of the Level 1.5 product. They also provide information on the quality and completeness of the Level 1.0 Image from which the Level 1.5 Image Product was derived, see Typical geometric accuracy for MSG-1/2 (PDF, 34 KB).
Access to SEVIRI near real-time and offline data and products typically involves an initial registration process. For further information, please visit our Data Access section, or register on the EO Portal.