DEM GENERATION and OCEAN TIDE MODELING using InSAR

Accurate knowledge of the Antarctic ice sheet mass balance plays an important role on the global sea level change. Here two-pass differential InSAR (DInSAR) technique is applied for tidal signal modeling underneath the Sulzberger ice shelf, West Antarctica. The fine resolution DEM over grounded ice and ice shelf, obtained by combining ERS-1/2 tandem InSAR and ICESat laser altimetry, has been used to correct the topography phase from interferograms, resulting in a more accurate time series of vertical deformation measurements. In this study, it is demonstrated for the first time, that observable tidal constituents can be estimated underneath an ice shelf (ice tongue) using an InSAR time series. In particular, it is shown that the time series of observed tidal differences from InSAR agrees well with a number of global/regional ocean tide models such as NAO.99b, TPXO.6.2, GOT00.2, CATS02.01, and FES2004 with the regional model, CATS02.01, having the best agreement. The technique developed here can be applied to other regions where tide modeling is poor in accuracy and resolution.