Propagation Effects for Satellite Mounted Radars and Remote Sensing by Active Microwave SAR Sensors for Frequencies of X-band up to Ka-band

Abstract

Since the development of microwave sensors using higher frequency bands is topical and on the agenda of several space agencies, there is an actual demand to further investigate tropospheric propagation effects and related issues in more detail. We address the problem of tropospheric propagation for satellite mounted radars and remote sensing by active microwave SAR sensors for frequencies of X-band, up to Ka-band. Strong effects can be observed due to attenuation from rain including backscattering; where fog, clouds and gaseous attenuation also, come into play for propagating signals in the respective higher bands. We estimate and quantify the probability of occurrence of diverse effects and show how attenuation due to rain might lead to useful information about the rain intensity. Such intensity measurements of precipitation are sought in regions where ground based weather radars are lacking and are in need for modelling of precipitation effects and probabilities of attenuation for communication applications. Not only point-to-point line-of-sight measurements are required but areal information of attenuation also, which can be considered as a potential application to be deduced from two-dimensional synthetic aperture radar images. Measurements from highly-successful recently-launched TanDEM-X/ Terra-SAR-X sensors will be used for analysis and illustration.