Rapid Scan Data

The SEVIRI instrument onboard the MSG satellites normally scan the full earth disc every 15 minutes. By scanning a smaller area scans can be conducted more frequently. If only a third of the earth disc is scanned, it takes a third of the time to scan the area — in this case every five minutes instead of every 15 minutes (Figure 1). This is known as rapid scanning.

The MSG Rapid Scanning Service (RSS) follows on from the Meteosat First Generation (MFG) Meteosat-6 RSS, which ended in 2007.  The MSG Rapid Scan service which commenced on 13 May 2008, delivers Rapid Scan High Rate SEVIRI image data, as well as a selection of advanced meteorological products from a position at 9.5°E.

Figure 1: RSS 5-minute scan of reduced area (Click to enlarge)

RSS Scan Pattern

The baseline scan region is an area that corresponds approximately to the top third of a nominal repeat cycle. The service generates image data at five-minute intervals — the same as currently used for weather radars. The rapid scan area for the MSG RSS covers a latitude range from approximately 15° to 70°.

RSS data dissemination is identical to normal dissemination. Image segments are based on 464 lines, which are compatible with the full disk level 1.5 data scans.

The scans start 00:00, 00:05, 00:10, 00:15 ... etc. (five-minute scans).  For channels 1 to 11, only segments 6 to 8 are disseminated. For the High Resolution Visible Channel only segments 16 to 24 are disseminated. Epilogue and prologue (L1.5 Header and L1.5 Trailer) have the same structure. Calibration is identical to Full Earth Scan (FES). Image rectification is to 9.5°E.  The MSG Level 1.5 Image Product Effective Radiance Definition applied.

Planned Service Interruptions

The rapid scanning service is periodically interrupted for short periods of time. These temporary outages are used to exercise the instrument mechanics in Full Earth Scan, which is required to keep the mechanism in good repair. In addition, this period is used for essential maintenance activities. The period between rapid scanning sessions is not disseminated.

The baseline operational period for MSG RSS is 26 days of continuous rapid scanning followed by two days of full earth disc scanning, over 11 months per year. The 12th month (typically around December and January) is devoted to either FES or no imaging.

Note: interruptions to RSS can be expected if the equipment used to provide the service is needed to support the Meteosat 0° Service.  The RSS Schedule has the latest information on planned monthly outages.

Meteorological Products

In addition to the High Rate SEVIRI product, meteorological products are also generated and disseminated to the user community in near real-time. For a comprehensive list, consult the Product Navigator.

Service Registration

Access to Rapid Scan 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 with the EO Portal.