Atmospheric Effects Removal of Asar-derived Insar Products Using Meris Data and Gps

As confirmed by many scientists, atmosphere has intensive contaminative role on Interferometric Synthetic Aperture Radar (InSAR) measurements. Atmospheric parameters, always influence radar’s phase but the intensity of the atmospheric errors on interferograms depend on the difference of the parameters’ values. In this paper, some calibration methods will be considered in order to reduce the errors in some scenes acquired in 2005 from Mashhad in North East of Iran which is a semi mountainous area. Therefore, model estimations and data acquiring processes were determined to sustain the climate’s requirements. Since we have used Advanced synthetic aperture Radar (ASAR) data for interferometry purpose, MERIS seemed to be an appropriate data source due to the exact similarity of the acquisition times of MERIS and ASAR. As water vapor products which derived from optical Spaceborn sensors are significantly sensitive to the clouds, a cloud mask algorithm was issued and an interpolation method was utilized to fill the empty pixels of the water vapor product. The air pressure and water vapor differential maps was formed in the next step and the derived differential maps was converted to zenith delay and radar phase shift respectively. As interferogram flattening was decided to be done after error removal process, the Ionospheric effect was neglected due to its linear influence in the area of interest. Implementing the model to the ASAR interferogram showed that the corrected InSAR results agreed to the independent GPS measurements with around a centimeter difference. Furthermore, atmospheric artifacts were significantly reduced in the final product.