A combined IR-microwave spaceborne cloud profiler

Studies of the energy budget of the Earth require information on cloud height and thickness. Spaceborne vertical-looking radars are being proposed to measure these parameters, but the power required to measure thinner clouds is relatively high, even at 94 GHz. The authors propose a combination of a low-power microwave radar and a laser radar (lidar) to measure most of the needed cloud profiles. They present an SNR study for such a system, along with candidate system parameters. The laser radar (operating at 10.6-μ wavelength) is effective in the case of thin clouds, such as cirrus clouds, while the microwave system handles denser and thicker clouds. A relatively low-power combination should be able to estimate effectively the cloud top and base.