1. Version 1.1, 02 February 2005 APPLICATIONS OF METEOSAT SECOND GENERATION (MSG) SNOW DETECTION Author:J. Kerkmann (EUMETSAT) (kerkmann@eumetsat.de) (kerkmann@eumetsat.de) Contributors:D. Rosenfeld (HUJ), H. Kocak (Turkey) H. J. Lutz (EUMETSAT)

2. Version 1.1, 02 February 2005 Snow and fog over Central and Eastern Europe 24 February 2003

3. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, HRV Channel Best channel to detect snow, but difficult to discriminate between snow and fog/low Stratus !!!

4. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, Channel 02 (VIS0.8) Shows less details compared to HRV channel ! (should not be used if HRV is available)

5. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, Channel 03 (NIR1.6) Very good discrimination between snow and water clouds !

6. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, Channel 04 (IR3.9) Also good discrimination between snow and water clouds !

7. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, Channel 04r (IR3.9r) Discrimination power of IR3.9 is in the solar/reflected component ! to see IR10.8

8. Version 1.1, 02 February 2005 MSG-1, 24 Feb 2003, 11:00 UTC, Diff. IR3.9 - IR10.8 Similar to IR3.9r (except for high, cold clouds) !

9. Version 1.1, 02 February 2005 Non-discrimination of snow and fog with the VIS0.8 channel 24 Feb 2003, 11:00 UTC High reflectance (snow, thick water clouds) Low reflectance (sea) Click on the icon to see the animation (11:00-12:45 UTC, AVI, 1373 KB) !

10. Version 1.1, 02 February 2005 High reflectance (water clouds) Low reflectance (snow, sea) Snow detection using the SEVIRI NIR 1.6 channel 24 Feb 2003 11:00 UTC Click on the icon to see the animation (11:00-12:45 UTC, AVI, 1242 KB) !

11. Version 1.1, 02 February 2005 Low reflectance (snow, sea) High reflectance (water clouds) Snow detection using the SEVIRI IR 3.9 channel 24 Feb 2003, 11:00 UTC Click on the icon to see the animation (11:00-12:45 UTC, AVI, 1479 KB) !

12. Version 1.1, 02 February 2005 Recommended RGB for snow/fog monitoring 24 Feb 2003, 11:00 UTC, RGB VIS0.8-NIR1.6-IR3.9r

13. Version 1.1, 02 February 2005 Alternative RGB for snow/fog monitoring 24 Feb 2003, 11:00 UTC, RGB NIR1.6-VIS0.8-VIS0.6

14. Version 1.1, 02 February 2005 Snow detection using SEVIRI HRV images 24 Feb 2003, 12:00 UTC, RGB HRV-HRV-IR10.8

15. Version 1.1, 02 February 2005 Snow and fog/low clouds over Central Europe 25 October 2003

16. Version 1.1, 02 February 2005 Snow & fog/low stratus as seen in VIS and NIR images 25 Oct 2003, 09:00 UTC VIS0.6 VIS0.8 NIR1.6

17. Version 1.1, 02 February 2005 Snow & fog/low stratus as seen in VIS0.8 and HRV images 25 Oct 2003, 09:00 UTC VIS0.8 HRV

18. Version 1.1, 02 February 2005 Snow & fog/low stratus as seen in IR images 25 Oct 2003, 09:00 UTC IR3.9 IR10.8

19. Version 1.1, 02 February 2005 Recommended RGB for snow/fog monitoring 25 Oct 2003, 09:00 UTC, RGB VIS0.8-NIR1.6-IR3.9r

20. Version 1.1, 02 February 2005 Alternative RGB for snow/fog monitoring 25 Oct 2003, 09:00 UTC, RGB NIR1.6-VIS0.8-VIS0.6

21. Version 1.1, 02 February 2005 Final enhancements of the RGB composite can help to highlight snow/fog areas ! MSG-1 25 October 2003 09:00 UTC RGB Composite R = NIR1.6 G = VIS0.8 B = VIS0.6

22. Version 1.1, 02 February 2005 Snow detection using difference between NIR1.6 and VIS0.6 channels MSG-1 25 October 2003 09:00 UTC Difference Image NIR1.6-VIS0.6 Snow Index: (NIR1.6 - VIS0.6) / (NIR1.6 + VIS0.6)

23. Version 1.1, 02 February 2005 Zoom of previous image MSG-1 25 October 2003 09:00 UTC Difference Image NIR1.6-VIS0.6

24. Version 1.1, 02 February 2005 Snow over the Alps 26 September 2003

25. Version 1.1, 02 February 2005 Poor snow cover over the Alps during summer 2003 MSG-1 26 September 2003 09:30 UTC RGB Composite R = NIR1.6 G = VIS0.8 B = VIS0.6 snow

26. Version 1.1, 02 February 2005 Snow and clouds over Turkey 27 November 2004

27. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, HRV Channel Best channel to detect snow, but difficult to discriminate between snow and clouds !!!

28. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, Channel 02 (VIS0.8) Shows less details compared to HRV channel ! (should not be used if HRV is available)

29. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, Channel 03 (NIR1.6) Better discrimination between snow and water clouds !

30. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, Channel 04r (IR3.9r) Also good discrimination between snow and water clouds !

31. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, Diff. IR3.9 - IR10.8 Also good discrimination between snow and water clouds !

32. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, RGB VIS0.8-NIR1.6-IR3.9r Recommended RGB for discrimination between snow and clouds !

33. Version 1.1, 02 February 2005 MSG-1, 27 Nov 2004, 10:00 UTC, RGB NIR1.6-VIS0.8-VIS0.6 Alternative RGB for discrimination between snow and clouds !

34. Version 1.1, 02 February 2005 Melting fresh snow in the Po Valley, Italy 19 January 2005

35. Version 1.1, 02 February 2005 MSG-1, 19 Jan 2005, 09:00 UTC, RGB VIS0.8-NIR1.6-IR3.9r Recommended RGB for discrimination between snow and clouds !

36. Version 1.1, 02 February 2005 Click on the icon to see the animation (08:15-13:30 UTC, AVI, 6067 KB) ! MSG-1 19 January 2005 09:00 UTC RGB Composite R = HRV G = HRV B = IR10.8i

37. Version 1.1, 02 February 2005 Click on the icon to see the animation (09:00-14:00 UTC, AVI, 17064 KB) ! MSG-1 19 January 2005 09:00 UTC RGB Composite R = NIR1.6 G = HRV B = HRV

38. Version 1.1, 02 February 2005 SUMMARY

39. Version 1.1, 02 February 2005 Detection of Snow during Day-Time HRV: to disciminate between fog and ground (snow white, ground darker)HRV: to disciminate between fog and ground (snow white, ground darker) VIS0.6 and VIS0.8: less useful because of lower horizontal resolutionVIS0.6 and VIS0.8: less useful because of lower horizontal resolution NIR1.6, IR3.9, IR3.9r or IR3.9-IR10.8: to discriminate between fog/low clouds and snow (fog high reflectivity, snow low reflectivity)NIR1.6, IR3.9, IR3.9r or IR3.9-IR10.8: to discriminate between fog/low clouds and snow (fog high reflectivity, snow low reflectivity) Recommended RGB: 02-03-04r (VIS0.8-NIR1.6-IR3.9r)Recommended RGB: 02-03-04r (VIS0.8-NIR1.6-IR3.9r) Alternative RGB: 03-02-01 (NIR1.6-VIS0.8-VIS0.6)Alternative RGB: 03-02-01 (NIR1.6-VIS0.8-VIS0.6) Recommended RGB with HRV: 03-12-12 (NIR1.6, HRV, HRV)Recommended RGB with HRV: 03-12-12 (NIR1.6, HRV, HRV)

40. Version 1.1, 02 February 2005 Detection of Snow during Night-Time Snow detection at night is very difficult !Snow detection at night is very difficult ! RGB 10-09, 09-04, 09 to detect cloudsRGB 10-09, 09-04, 09 to detect clouds IR10.8 or IR3.9: to discriminate between snow and snow-free ground (only possible if snow colder than snow-free ground !)IR10.8 or IR3.9: to discriminate between snow and snow-free ground (only possible if snow colder than snow-free ground !)