Monitoring Active Volcanoes Using Advanced SAR Interferometric Methods

In volcanic areas, the effect of atmospheric propagation delays can be divided into two parts: the height-dependent component and the height-independent component. The height-dependent component is induced mainly due to the atmospheric vertical stratification and thus defined as stratified atmospheric delay. It has a great impact on interferograms due to the presence of topographic variations. In this paper, we present an effective method to mitigate the stratified atmospheric delay using global 4-d Numerical Weather Prediction (NWP) products. Moreover, the formation and the impact of stratified delays are demonstrated based on NWP products at Stromboli volcano. Persistent Scatterer Interferometry (PSI) processing has been performed on four stacks of TerraSAR-X High Resolution Spotlight (HRSL) data after compensation of stratified effects. In order to retrieve the 3-d deformation vector map, four independent stacks are fused using the Iterative Closest Point (ICP) algorithm. Finally, we analyze and validate fused PSI results based on literatures, which show a good agreement.