Colour Interpretation Guide

water clouds

Meteosat Second Generation

HRV Fog RGB - Recipe

Red: NIR1.6
Green: HRV
Blue: HRV

Fog and water clouds

Fog and water clouds appear light pink in the HRV Fog RGB images.

The images left and below show water clouds, fogs in HRV Fog RGB images. This RGB type due to its high resolution is very useful to detect valley fogs.

water clouds
Meteosat, SEVIRI HRV Fog RGB for 14 October 2010, 07:40 UTC

The image below shows a situation when fog and/or low clouds formed over snow covered surface. The fog and stratus clouds are easy to discriminate from the snow covered surface due to the good colour contrast between the cyan and the light pink colours.

snow covered land
Meteosat, SEVIRI HRV Fog RGB for 28 November 2013, 07:40 UTC

Explanation of the colour of fog and water clouds (see also the recipe on the left side):

The reflectivity values of water clouds are around medium strong both in NIR1.6 and HRV channels. However, after the linear stretching the signal becomes higher in the red then in the other two colour beams. As a consequence water clouds appear pinkish in the HRV Fog RGB images.