# SEVIRI RGB Cal Module - part II

## Print Version

## Chapter VI: Summary

### Table of Contents

- Chapter VI: Summary
- Summary according to the RGB types
- Summary according to the applications

### Summary according to the RGB types

HRV Fog RGB
High resolution provides good details of different features. Best used for detection of low clouds and fog, good separation from snow. Especially valley fog can be monitored quite well. This RGB is suitable to prepare images for media.
| Low clouds and fog (pinkish) Snow (cyan)

Snow RGB
Daytime RGB to monitor snow and to monitor low clouds or fog over snow.
| Snow (red-orange) Low cloud and fog (white)

Night Microphysics RGB
Nighttime RGB to monitor low clouds and fogs, to separate them from cloud-free surface.
| Low cloud and fog (light greenish, yellowish) Land (pinkish) Sea (bluish)

Ash RGB
RGB can be used day & night. Similar to Dust RGB, but tuned for volcanic ash and SO2 gas plume detection.
| Volcanic ash (red) SO2 gas plume (green)

### Summary according to the applications

Full cloud analysis
During daytime: Day Microphysics RGB 24 hour Microphysics RGB Natural Colours RGB | During nighttime: Night Microphysics RGB 24 hour Microphysics RGB

Cyclogenesis
The stratospheric dry air protruding down is a signal for cyclogenesis. It can be best seen with the Airmass RGB having WV6.2, WV7.3 and IR9.7 (ozone channel) in it. During day and nighttime: Airmass RGB

Convection
The microphysics of the cells helps to identify thunderstorms with severe updrafts. The HRV Cloud RGB provides information about the cloud top features in good spatial resolution.
During daytime Day Microphysics RGB Severe Storms RGB HRV Cloud RGB | During nighttime: Enhanced IR10.8 (not shown here) Dust RGB (helps to identify cirrus shield) Airmass RGB

Low clouds and fog
During daytime HRV Fog RGB 24hour Microphysics RGB Day Microphysics RGB Snow RGB | During nighttime Night Microphysics RGB 24hour Microphysics RGB

Atmospheric particles and trace gases
Dust clouds: Dust RGB
Volcanic ash clouds: Ash RGB (Dust RGB)
Volcanic SO2 gas plumes: Ash RGB (Dust RGB)

Land applications
Snow: Day Microphysics RGB Natural Colour RGB HRV Fog RGB Snow RGB
Floods: HRV Fog RGB Natural Colour RGB
Vegetation: Natural Colours RGB
Forest Fires: The IR3.9 channel is the most sensitive SEVIRI channel to sub-pixel sized fires.
During daytime: Day Microphysics RGB (hot spots) HRV Fog RGB (smoke) HRV Cloud RGB (smoke) Natural Colours RGB (smoke) Fire RGB (IR3.9; VIS0.8, HRV) for media (not shown here) | During nighttime: Night Microphysics RGB (hot spots)