Atmospheric Delay Correction in TerraSAR-X by MERIS, MODIS and GPS
Jafari, Soheyla1; Motagh, Mahdi2; Vajedian, Sanaz3
1University of Tafresh, IRAN, ISLAMIC REPUBLIC OF; 2GFZ, GERMANY; 3University of Tehran, IRAN, ISLAMIC REPUBLIC OF
Accurate correction of atmospheric water-vapor effects enhances the ability of InSAR technique to effectively map surface deformation associated with small amplitude geophysical processes. Several methods have been suggested in the past for mitigating such effects in SAR interferograms for deformation analysis. Calibrating methods use independent data from external observations such as GPS networks and space-based measurements to reduce atmospheric effects. The water vapor information obtained from NASA Moderate Resolution Imaging Spectroradiometer (MODIS) or Medium Resolution Imaging Spectrometer (MERIS) on board the European Space Agency (ESA)'s Envisat platform have also been successfully applied for InSAR atmospheric corrections in C-band interferograms.
In this paper we evaluate the potential of MODIS and MERIS products for atmospheric corrections of high-resolution SAR interferograms from TerraSAR-X satellite. The TerraSAR-X measurement with a horizontal resolution of 3 m is an ideal data source to detect small-scale deformation associated with geophysical processes such as landslides and sinkholes. However, main disadvantages of TerraSAR-X data are their higher vulnerability to atmospheric effects, in turn compromising the interpretation of small amplitude deformation signal in X-band interferograms. We develop a metrology for InSAR water vapor correction by integrating observations from GPS, MODIS and MERIS data and apply the correction to X-band interferograms over a landslide region south of Uzgen in Kyrgyzstan, Central Asia. The corrected interferograms are then used to assess slope stability associated with landslides in the region.