Spatio-Temporal Tropospheric Variability in Sar Interferograms with Extremely High Temporal Resolution

Abstract

Atmospheric delay induces spatial phase errors and decorrelation in synthetic aperture radar (SAR) interferometry, especially in extreme weather conditions. For SAR missions, the atmosphere is considered to be spatio-temporally frozen during the aperture integration time, which is correct for Low Earth Orbit (LEO) SAR systems. However, this assumption may be inappropriate for Geosynchronous Earth Orbit (GEO) SAR since it can deploy a much longer integration time. Here we simulate a sequence of refractivity distributions with a high spatio-temporal resolution to analyze the spatio-temporal variable troposphere. The impacts of both frozen flow shift and turbulent delay in the time series in-terferograms are obtained, showing that tropospheric delay varies rapidly and may lead to phase decorrelaton within a few minutes.