Applications of Microwaves to Remote Sensing

Extensive theoretical studies as well as laboratory and field measurements of rough-surface scattering and emission from agricultural soil and sea surface and of volume scattering and emission from snow and vegetation yield a considerable comprehension of the interaction of microwaves with the molecular properties and the geometrical features of these media. Hence algorithms have been derived which allow the interpretation of air- and space-borne radiometer- and radar-data in terms of natural parameters. The absorption lines of atmospheric constituents in the millimeter wave range can be utilized to measure with radiometers various trace gases and other parameters, like temperature, throughout the strato-and mesosphere. Knowledge of spectroscopic parameters of the considered molecules, high spectral resolution of the measured lines and special inversion algorithms of the radiation transfer allow the determination of the height distribution of constituents and temperature with a resolution of less than 10 km.