Two periods of geodetic glacier mass balance at Eastern Nyainqentanglha derived from multi-platform bistatic SAR interferometry

Abstract

Bistatic SAR interferometry is an essential technique of observing glacier height changes and geodetic mass balance. Eastern Nyainqentanglha distributes the majority parts of monsoonal temperate glaciers and presented the quickest glacier mass loss rate at High-mountains Asia. Most recent studies on glacier mass balance at High-mountains Asia focus on the decadal-scale. Here we obtained TerraSAR-X/TanDEM-X SAR images observed in ∼2012 and ∼2017, together with the SRTM DEM that observed in 2000 we derived geodetic glacier mass balances in two periods (2000 - ∼2012/∼2012 - ∼2017). We proposed three InSAR processing procedures for deriving geodetic glacier mass balance of the second period, which yielded basically identical results. Topography differencing between two DEMs derived both by TerraSAR-X/TanDEM-X can provide geodetic glacier mass balance information at a sub-decadal scale. The patterns of glacier mass balance were almost identical before and after ∼2012 and showed with slightly increasing rates of mass loss. Glaciers distributed at the southeastern, which were most clean-ice type, presented with quicker loss rates than the glaciers at the northwestern part, which were most debris-covered type. Yanong glacier, which was the largest glacier and belong to lake-terminating type showed the quickest mass loss rate. Decreasing precipitation, increasing temperature and downward shortwave radiation could be responsible for the quick glacier mass loss.