Reduction of atmospheric water vapour effects on ENVISAT ASAR interferograms using MERIS near IR measurements

Abstract

Atmospheric water vapour effects represent a major limitation of repeat-pass Interferometric SAR (InSAR) techniques including InSAR time series approaches (e.g. permanent scatterers (PS) and small baseline subset (SBAS)). In this paper, it is demonstrated that atmospheric water vapour effects greater than 4 cm can be observed even in desert regions (e.g. Southern California) and the use of MERIS correction model can improve the accuracy of InSAR derived deformation signals from 9.9 mm to 4.1 mm. It is also shown that, using an advanced integration technique titled InSAR Time Series with Water Vapour correction model (InSAR TS + PWV) for reduction of water vapour effects with coincident MERIS near IR water vapour data, a time series of postseismic motion after the 2003 Bam (Iran) earthquake is achievable with about 50% reduction in RMS model misfit. It is believed that this study not only contributes directly to the ENVISAT mission, but also will benefit space agencies’ plans to design and launch InSAR missions because it aids in the identification of necessary characteristics of their future InSAR missions