High-mountain glacier areas are of great interest for studying climate-related changes and freshwater supply, especially in Central Asia, where water distribution is uneven. The Inylchek glacier is one of the largest glaciers in the world, formed by the northern and southern valley glacier streams. Near the junction of the two tributaries, the pro-glacial ice-dammed Lake Merzbacher is formed by the accumulation of meltwater from the northern Inylchek Glacier and is blocked by the southern stream. During summer, the lake completely drains within a few days through subglacial channels. These glacier lake outburst floods (GLOFs) occur regularly, at least once a year. 

In August 2009, GFZ and the Central Asian Institute of Geosciences (CAIAG, Kyrgyzstan) installed the first GNSS and meteorological station adjacent to Lake Merzbacher as part of the Global Change Observatory Central Asia activities. 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. 

The ice dam is strongly influenced by the formation and outburst of the lake, regardless of the general motion during the year. The vertical position and surface velocities increase shortly before the GLOF, which confirms that the ice-dam adjacent to the lake became afloat. After the GLOF, the elevation decreased rapidly by 20m in 2014 within eight days. In 2015, the GLOF changes in timing, magnitude, and available lake water volume, but the behavior 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.

Project partners:

• Central Asian Institute for Applied Geosciences (CAIAG)

Project duration:

• 2008 – 2019

Budget:

• GFZ Funding through GCOCA

Project-related publications:

• Zech, C., Schöne, T., Neelmeijer, J., Zubovich, A., Galas, R. (2016): Geodetic Monitoring Networks: GNSS-derived Galcier Surface Velocities at the Global Change Observatory Inylchek (Kyrgyzstan). - In: Rizos, C., Willis, P. (Eds.), IAG 150 Years: Proceedings of the IAG Scientific Assembly in Postdam, Germany, 2013, (International Association of Geodesy Symposia; 143), Cham: Springer International Publishing, 557-563. https://doi.org/10.1007/1345_2015_38
• Zech, C., Schöne, T., Neelmeijer, J., Zubovich, A. (2018): Continuous Kinematic GPS Monitoring of a Glacier Lake Outburst Flood. - In: International Symposium on Earth and Environmental Sciences for Future Generations, (International Association of Geodesy Symposia; 147), Cham: Springer, Online 2016, 339-347. https://doi.org/10.1007/1345_2016_246