Antarctic Ice Shelf Tide Modeling Using PALSAR Interferometry

The knowledge of ocean tides underneath permanently or seasonally sea ice covered ocean and ice shelves over Antarctica, is largely unknown. Significant amount of West Antarctic ice sheet melt is through the mechanism of basal melting and due to turbulent tidal mixing. Knowledge of the ice shelf grounding lines and their extent, are critical to accurately quantify ice sheet mass balance, and ocean tides are well known to significantly shift the grounding lines. Seasonal variability of ocean tides, especially underneath the ice shelves, adds to the complexity of the problem of accurate ice sheet mass balance studies. First, we demonstrate the feasibility of fine spatial scale (as fine as 100 m or less) O1 barotropic ocean tide modeling undernearth the Sulzberger ice shelf, West Antarctica, using the VV-polarized C-band ERS-1/-2 tandem mission two-pass SAR interferometry time series. The tidal inversion is accomplished by first developing a 60-m resolution DEM over the ground ice and the adjacent ice shelves using ERS tadem InSAR and ICESat altimetry, thereby diminishing the stringent data requirement in fourpass InSAR for tidal analysis. Here we present a status report to use the ALOS PALSAR and other complementary data sets (ICESat laser and ENVISAT radar altimetry, GRACE) for multi-resolution (as fine as 100 m using InSAR) barotropic tide modeling and ice mass balance studies planned for and near the major Antarctic Ice Shelves, including the Filchner-Ronne, Ross, Larsen, and Amery Ice Shelves, and Antarctic Peninsula.