Microwave radiometer

Microwave radiometers (MicroWave Radiometers), abbreviated MWR , are instruments for observing the earth's surface in the frequency range of microwaves . They can be:

• active - by emitting the waves and measuring the reflected radiation, or
• passive - by measuring the earth's natural radiation .

The particular importance of the microwave radiometer for remote sensing lies in the fact that it responds strongly to water vapor , which can be used for soil analysis on the one hand , and for measuring atmospheric moisture on the other .

Many earth observation satellites - such as the ERS and Envisat series - carry such radiometers, but measuring aircraft are also equipped with them.

For example, the passive microwave radiometers of the European satellites ERS-1 and ERS-2 work in the radio frequencies 23.8 and 36.5 GHz to measure the water vapor content in the troposphere. The two frequencies allow further analyzes. The amount of atmospheric water vapor is the exact reduction of electronic distance measurements as GPS and radar - altimetry necessary because he and the floating water droplets increase the apparent path of the echo signal. These microwave data are also useful for meteorology .

See also:

• Weather satellite
• Moisture profiles

literature

• Karl Kraus & Werner Schneider: Remote sensing, Volume 1 (physical basics and recording techniques) , 305 pages. Dümmler-Verlag, Bonn 1988
• Dieter Gottschalk: ERS-1 Mission and System Overview . The Geosciences, Volume 1991