Conference Agenda

Bistatic SAR interferometry is an essential technique of satellite geodesy and is capable of observing glacier height changes. Most recent studies focus on the decadal scale due to limitations of data acquisition and precision. Eastern Nyainqentanglha distributes the majority parts of maritime glaciers and presents with the quickest glacier mass loss rate at High-mountains Asia. Here we obtained two epochs of TerraSAR-X/TanDEM-X SAR images observed in ~2012 and ~2017. Together with the SRTM topography data that observed in 2000 we derived geodetic glacier mass balances in two periods (2000 - ~2012 / ~2012 - ~2017). We proposed three InSAR procedures for deriving the second period, which yields basically identical results of geodetic glacier mass balance. Topography differencing between DEMs derived by TerraSAR-X/TanDEM-X shows better precision than between TerraSAR-X/TanDEM-X and SRTM, and are capable of providing geodetic glacier mass balance information at sub-decadal scale. The patterns of glacier mass balance are almost identical before and after ~2012 and show with slightly increasing glacier loss rate. The increase of glacier height downwasting was more severe at lower sections. Glaciers distribute at the southeastern present with quicker lost rates than the northwestern part.

The cryosphere in high elevation regions is sensitive to the effects of climate change. Meltwater from the cryosphere contributes a significant fraction of the freshwater resources in China and in the countries receiving water from the Third Pole. Within the ESA Dragon 4 project we investigated glacier mass changes in different regions using multi-temporal stereo satellite imagery since the 1960s. Detailed investigations including mapping of rock glaciers have been performed in the Poiqu basin in central Himalaya. Results reveal that in most regions glacier mass loss continuously accelerated and that even in regions where glaciers have been in balance with climate mass loss now prevails. The greatest mass loss has been found in Northern Tien Shan and the Central Himalaya with mass loss rates between 0.35 and 0.40 mw.e.a^-1 and the lowest in eastern Pamir (~0.05 mw.e.a^-1). The mass loss has been primarily driven by an increase in summer temperature and is further accelerated by proglacial lakes which have become abundant in most regions with the ongoing glacier recession. The glacial lake area in Poiqu basin more than doubled between 1964 and 2017 from about 9.7 km² to more than 20 km². At the same time glaciers were shrinking at a rate of more than 0.5% per year. Rock glaciers are abundant in Poiqu region covering about 21 km², with is more than 10% of the glacier area (about 190 km²) in 2015. With ongoing glacier wastage the rock glaciers can become an increasingly important water resource.