Combined use of InSAR and ICESat/GLAS data for high accuracy DEM generation on Antarctica

This study aims to use ICESat /GLAS data for correction of DEM made from Interferometric SAR data instead of traditional Ground Control Points (GCPs) collected by ground survey. GLAS is a laser altimeter system and it can measure the earth surface topography with ultimate vertical accuracy (+/- 14cm) and high spatial accuracy (+/- 15m). Therefore, we can treat CLAS data for the reference of height and position on Antarctic ice sheet. We applied this method at south of Breivika. The elevation values derived by ERS-1/2 InSAR DEM have insufficient height accuracy compared to GLAS data due to insufficient baseline estimation, ice flow appeared in the fringe pattern, and difficulty of phase unwrapping, which is RMS +/- 284.0m compared with GLAS data. After the correction of InSAR DEM using GLAS data, it improved to +/- 32.6m. Next, we validated this result using the 28(th) JARE (Japanese Antarctic Research Expedition) GPS survey result. The RMS height difference between JARE GPS result and corrected InSAR DEM showed +/- 39.5m. The result showed that our correction method works quite well and we can produce spatially dense and high accuracy DEM along with Antarctic coast line. The one remaining problem is how to reduce the effect of ice flow appeared in the fringe pattern.