Snow and ice on the ground

Snow and ice on the ground appear yellow in the HRV Cloud RGB images.

Snow and ice on the ground strongly reflect short wave solar radiation, hence the strong intensity of the red and green colour beam (red + green = yellow). The albedo of snow on plane ground differs from the albedo of snow and ice in the mountains as can be seen on the image below. This difference arrises from the vegetation cover disrupting the uniform snow cover (e.g. trees) compared to the vegetationless mountains.

The blue colour contribution from the window channel IR10.8 has an average value over snow caused by its relatively warm temperature compared to clouds. In case of temperature inversions with very cold temperatures on the ground, the blue contribution is smaller in mountain regions than in the surrounding land. This also enhances the yellow hue of the snow on mountains.

HRV Cloud RGB from 8 February 2012, 12:00 UTC

Explanation of the yellow colour of snow and ice on the ground in the HRV Cloud RGB (see the recipe):

• Only the HRV channel contributes notably to the HRV Cloud RGB for snow and ice on the ground. The addition of red and green results in a yellow hue.