The image service is the main mission of Meteosat Second Generation (MSG).  This service comprises High Rate SEVIRI image data, in 12 spectral bands from the satellite's field of view which are processed in near real-time to Level 1.5, i.e. the data are corrected for radiometric and geometric non-linearity, before onward distribution to the user. The data are accompanied by the appropriate ancillary information that allows the user to calculate the geographical position and radiance of any pixel.  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 5 SEVIRI spectral channels.  Data are compressed using lossy JPEG compression prior to onward distribution to the user.

The nominal coverage of the prime MSG service, the geostationary service from the MSG satellite located at 0 degrees longitude, 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 8 segments of image data, with the exception of 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 after the delivery of the segments 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.

Spectral Channels

High Rate SEVIRI image data consist of geographical arrays of various sizes of image pixels, each pixel containing 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 12th, the High Resolution Visible (HRV) channel, providing measurements with a resolution of 1 km:

SEVIRI Instrument Channels, running left to right (Click to enlarge)

Visible band centred on 0.6µm - Channel 1 (VIS 0.6)
Visible band centred on 0.8µm - Channel 2 (VIS 0.8)
Near-infrared band centred on 1.6µm - Channel 3 (IR 1.6)
Infrared band centred on 3.9µm - Channel 4 (IR 3.9)
Water Vapour band centred on 6.2µm - Channel 5 (WV 6.2)
Water Vapour band centred on 7.3µm - Channel 6 (WV 7.3)
Infrared band centred on 8.7µm - Channel 7 (IR 8.7)
Ozone band centred on 9.7µm - Channel 8 (IR 9.7: O3)
Infrared band centred on 10.8µm - Channel 9 (IR 10.8)
Infrared band centred on 12.0µm - Channel 10 (IR 12.0)
Carbon Dioxide band centred on 13.4µm - Channel 11 (IR 13.4: CO2)
Broadband high-resolution visible band - Channel 12 (HRV)

The Low Rate SEVIRI services comprises of only the following 5 of the above spectral channels:

Channel 1 (VIS 0.6)
Channel 3 (IR 1.6)
Channel 4 (IR 3.9)
Channel 5 (WV 6.2)
Channel 9 (IR 10.8)

An illustration of the fine detail visible with the HRV channel can be seen in this animation of HRV images covering Italy on 13 August 2005, from 06.45 to 17.45 UTC (AVI, 10.4 MB). The low-level clouds over the Po Valley in the morning are visible, as well as convection along the Appennines in the afternoon, producing cirrus anvils.

Scan Modes

The HRV channel supports a mode of operation known as 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. From the start of MSG routine operations until 31 August 2005, the HRV scanning mode was fixed as follows:

• Split position: Line 914
• E-W offset for lower window: Chosen to east-justify the image
• E-W position for upper window: Chosen to optimise the coverage of the European region

From 31 August 2005 onwards, the lower window shifts to follow the daily illumination. The configuration is as follows:

• Between 00:00 and 14:00 UT the lower HRV window is east-justified so as to optimise the coverage of the Indian Ocean region.
• Between 14:00 and 17:00 UTC the lower HRV window moves every hour, on the hour incrementally westwards, until in becomes west-justified.
• Between 17:00 and 00:00 UTC the lower HRV window is west-justified to optimise the coverage of the Atlantic Ocean.

Animation of the HRV lower window configuration from 22 June 2005, 00:00-24:00 UTC, (AVI, 2.26 MB).

Quality Indicators

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, as well as 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, 18 KB).

Further Reading

MSG Ground Segment Mission Specific Implementation Plan (PDF, 820 KB).

MSG Level 1.5 Image Data Format Description (PDF, 1.5 MB).

MSG Level 1.5 Image Product Quality Indicators (PDF, 266 KB). 

Service Registration

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.