Influence of hydrometeors on InSAR observations

Repeat-pass synthetic aperture radar interferometry is an important tool for measuring Earth surface topography and/or surface deformations. These observations, however, are highly affected by the atmosphere. Therefore, an accurate description of atmospheric distortions is very important to improve an accuracy of interferometric measurements. In this paper we discuss influence of hydrometeors on the microwave propagation. On examples of two interferograms we show that there is a strong increase in a propagation delay associated with rain. To validate this observation we have used weather radar measurements to estimate contribution of rain droplets on the propagation path. It is shown that in some cases, a rain induced propagation delay can be of several centimetres.