Measuring Cloud Temperature
How do you measure the temperature of clouds?
The way that it is done by satellite sensors is to detect the
wavelength of infrared light emitted by the clouds. The colder
the cloud, the less infrared they emit, and the longer the
Department of Physics and Astronomy
University of Wyoming
There are thermal sensors and optical sensors that can register
the temperature of a portion of a cloud. However, a cloud usually
does not have a single temperature. A cloud is a three dimensional
dynamic mixture of water vapor, liquid water, and air. So its
temperature can change both with position and time.
Whether from the ground or from a satellite, an instrument that
measures the intensity of infrared radiation (which is then
translated into temperature) is usually used to measure the
temperature of the cloud. However, this temperature is biased
by the cloud droplets that are nearest the edge or side of the
cloud that is being viewed. For instance, the cloud temperature
that is seen by satellite sensors is usually referred to as the
temperature of the top of the cloud.
Radiosondes sometimes penetrate clouds, as do commercial aircraft,
providing measurements of the interior of clouds. Other remote
sensing devices are presently being tested that can provide some
information on interior cloud temperatures, but they are not in
wide-scale routine use yet.
David R. Cook
Climate Research Section
Environmental Science Division
Argonne National Laboratory
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Update: June 2012