Atmospheric correction for InSAR and its application in mapping ground motion due to interseismic strain accumulation

It is essential to correct the atmospheric error for measuring interseismic deformation in the order of mm/a. In this paper, Laohushan fault on the northeastern margin of the Tibetan Plateau is chosen as the study area. In order to derive the accurate interseismic deformation field, we evaluate three atmospheric correction methods (MERIS, ERA-Ⅰ, WRF) based on the corrected results on interferograms with small temporal-baselines. The optimal atmospheric correction methods and orbital correction methods are applied to correct errors in the large-temporal-baseline interferograms, then the average interseismic deformation fields are achieved by stacking the atmosphere and orbit-corrected interferograms. Our results show that the MERIS and ERA-Ⅰ are more suitable to be used to correct the atmospheric effect in ASAR interferograms than WRF in Haiyuan fault system area; on the other hand, the MERIS-corrected and ERA-Ⅰ-corrected deformation rate fields show a similar pattern of left-lateral displacement across the Laohushan fault, and the profiles across the fault show that the line-of-sight velocity across the fault is 2.5 mm/a, which is equal to 6.5 mm/a parallel to the fault and accords well with GPS observations. In addition, there is a large displacement gradient within 5 km near the fault, revealing shallow creep near the surface.