High-Resolution Visible (HRV) images from Western Africa, Antarctica and Brazil.
21 October 2020
22 June 2005
by Jochen Kerkmann and Sally Wannop (EUMETSAT)
The Meteosat Second Generation (MSG) High-Resolution Visible (HRV) channel supports a mode of operation known as Alternative HRV Scanning Mode Operations. In this mode it is possible to introduce a split of the HRV image into an upper (European) part and a lower (African) part. It is also possible to separately specify the East-West offset for the two parts of the HRV image.
Since the start of Meteosat-8 routine operations in January 2004 the HRV scanning mode has been fixed as follows:
- Split position: line 914.
- East-West offset for the lower window: chosen to east justify the image;=.
- East-West offset for the upper window: chosen to optimise the coverage of the European region.
The current position of the lower window is used to optimise the monitoring of Tropical storms over the Indian Ocean. Example showing the position of the upper and lower HRV window (31 October 2003, 11:30 UTC).
Following requests from users for further enhancements to the lower HRV window coverage, it has been decided to shift the HRV window to follow the daily illumination. The upper HRV window will not change, i.e. it will remain focussed over the European region. Therefore, from 31 August 2005 onwards, the configuration will be as follows:
- Between 00:00 and 14:00 UTC 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 it 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 and South America.
On 22 June 2005 a 24-h test was performed with the new HRV scanning pattern. The result, i.e. the 24-h animation of the HRV channel, can be seen/downloaded by clicking on the following link (Animation , 22 June 2005, 00:00–24:00 UTC, HRV channel, AVI). The animation nicely shows how the lower HRV window follows the evening terminator, as described above.
The four HRV images below were taken on the same day (22 June 2005). They show areas of the earth that so far have not been covered by the HRV channel (except in occasion of some tests during the MSG-1 commissioning phase). The upper images show the regions of Mauritania and Senegal in West Africa.
The details of the coastline and of the Sahara desert are impressive. When looking at the upper left image one almost gets the impression of seeing individual cumulus clouds (and their respective shadows on the ground). The lower images show scenes over Antarctica and Brazil, respectively. They show a cold air outbreak from the Antarctic towards the Southern Atlantic Ocean (lower left image) and cellular cloudiness over the Amazon basin (lower right image). In the latter image, one can also see many details of the Amazon river, forming many lake-type structures (probably side arms of the main river).
Meteosat-8 HRV Images
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