High-mountain glacier areas are of great interest to study climate related changes and fresh water supply especially in Central Asia where water is non-uniformly distributed over the entire region. The Inylchek glacier is one of the largest glaciers of the World and is formed by the northern and southern valley glacier stream. Near the junction point of both tributaries, the pro-glacial ice-dammed Lake Merzbacher is formed by the accumulation of melt-water of the northern Inylchek Glacier and is blocked by the southern stream. During summer time, the lake completely drains within a few days through sub-glacial channels. These glacier lake outburst floods (GLOF) occur regularly at least once a year.
In August 2009, GFZ and the Central Asian Institute of Geosciences (CAIAG, Kyrgyzstan) jointly installed the first GNSS and meteorological station adjacent to the Lake Merzbacher as part of the activities within the Global Change Observatory Central Asia. A year later, the station was replaced with a CAWa ROMPS station. Over the past years, several additional sensors have extended to the local network providing meteorological, hydrological, GPS and seismic data as well as optical cameras that support the monitoring of the GLOF. To directly investigate the behavior of the ice-dam especially during the GLOF, a continuously operating GPS station (ICED) has been installed providing 1Hz GPS data.
Irrespective of the general motion during the year, the ice-dam is strongly influenced by the formation and outburst of the lake. Especially the vertical position and surface velocities increase shortly before the GLOF supporting the assumption that the ice-dam adjacent to the lake became afloat. After the GLOF, the elevation decreases rapidly by 20m in 2014 within eight days. In 2015, the GLOF changes in timing, magnitude and available lake water volume but the behaviour of the ice-dam is similar compared to the year before. These comparable results have the potential to develop an early warning system for the glacier-dammed lake outburst flood.
In addition to the study of the GLOF, the data is used for modeling glacier systems, climate impacts, but also as ground truth for the CryoSat-2 SIRAL altimetry.