Feature Identification » Identifying Atmospheric Features » Cloud Heights

The easiest way to determine a cloud’s height is to use the visible channel to determine its type based on its texture, shape, and shadows. The cloud type then tells you its height.

Type of cloud

Height

Cirrus, cirrostratus, and cirrocumulus

High clouds at 6000-13000 m (~20000-43000 ft)

Altocumulus and altostratus

Mid-level clouds at 2000-6000 m (~6500-20000ft)

Stratocumulus and stratus

Low-level clouds at 0-2000 m (0- ~6500ft)

This works for most clouds, but not for those with large vertical extent. Cumuliform clouds can be found from 0-13000 m, depending on their stage of development.

Other factors can complicate cloud identification in visible imagery. For example, as the images below show, sun angle can make the same clouds look dramatically different at different times of day. Knowing where the sun is with relation to the clouds is the only way to combat this effect.

Visible Morning

EUMETSAT visible over Africa, 0600 UTC 19 Dec 2016

Visible Mid-day

EUMETSAT visible over Africa, 1200 UTC 19 Dec 2016

Visible Evening

EUMETSAT visible over Africa, 1800 UTC 19 Dec 2016

There’s another, more quantitative, way to identify cloud heights—using the brightness temperature of clouds in infrared images and RGBs made from those channels. Since IR channels are involved, the technique works during both day and night.

Assuming that tropospheric temperatures decrease with increasing height from the surface, lighter-colored clouds are colder and higher, while darker-colored clouds are warmer and lower. This rule works for both infrared and water vapour imagery. It’s more difficult to define the exact cloud height in RGBs, but we will practice using multiple products together to get an idea if clouds are high or low.

The ten basic cloud types in Earth's atmosphere.

Let’s practice identifying cloud height by using single channel imagery and RGBs and comparing the different products.

Question

Left Side Image
IR
Right Side Image
left side product right side product

Use the slider to compare the clouds at each location in the four products. Then identify the height of the clouds at each location.

a) Location A:
Please make a selection.
b) Location B:
Please make a selection.
c) Location C:
Please make a selection.
d) Location D:
Please make a selection.

The warm brightness temperatures in the IR and the greenish coloration in the night microphysics RGB tell us that Location A has very low, water clouds. The WV channel and dust RGB cannot detect them since they are too low.

We know that Location B has high clouds since they are bright white in the IR and WV imagery, and red in the night microphysics and dust RGBs.

The clouds at Location C are mid-grey in the IR image and therefore mid-level. They are brownish to yellowish in the night microphysics and dust RGBs but too low to be seen by the WV channel.

The clouds at Location D are mid-grey in the IR imagery, brown in the dust RGB, and pink in the night microphysics RGB. They cannot be seen in the WV image. These clues tell us that the clouds are slightly higher at Location D than Location C but likely still in the middle of the troposphere.

Please make a selection.

The hardest clouds to differentiate are overlapping clouds - especially where low clouds and/or fog occurs near snow cover. Snow and low clouds often have similar brightness temperatures, especially overnight.

Another difficulty occurs when the upper cloud is very thin. If the upper cloud is more translucent than those below it, the cloud mass brightness temperatures will average out to be warmer and thus at a lower altitude.