EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Glacier runoff variation since 1981 in the upper Naryn river catchments, Central Tien Shan

Tomas Saks1, Eric Pohl1, Horst Machguth1, Amaury Dehecq2,3,4, Martina Barandun5,1, Ruslan Kenzhebaev6, Olga Kalashnikova6, and Martin Hoelzle1
Tomas Saks et al.
  • 1Department of Geosciences, University of Fribourg, Fribourg, Switzerland
  • 2University Grenoble Alpes, CNRS, IRD, IGE, F-38000 Grenoble, France
  • 3Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
  • 4Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
  • 5Institute of Earth Observation, EURAC, Bolzano, Italy
  • 6Department 2 " Climate, Water and Natural Resources ", Central-Asian Institute for Applied Geosciences, Bishkek, Kyrgyzstan

Water resources in Central Asia strongly depend on glaciers, which in turn adjust their size in response to climate variations. We investigate glacier runoff in the period 1981–2019 in the upper Naryn basin, Kyrgyzstan. The basins contain more than 1000 glaciers, which cover a total area of 776 km2. We model the mass balance and runoff contribution of all glaciers with a simplified energy balance melt model and distributed accumulation model driven by ERA5 LAND re-analysis data for the time period of 1981 - 2019. The results are evaluated against discharge records, satellite-derived snow cover, stake readings from individual glaciers, and geodetic mass balances. Modelled glacier volume decreased by approximately 6.7 km3 or 14%, and the majority of the mass loss took place from 1996 until 2019. The decreasing trend is the result of increasingly negative summer mass balances whereas winter mass balances show no substantial trend. Analysis of the discharge data suggests an increasing runoff for the past two decades, which is, however only partly reflected in an increase of glacier melt. Moreover, the strongest increase in discharge is observed in winter, suggesting either a prolonged melting period and/or increased groundwater discharge. The average runoff from the glacierized areas in summer months (June to August) constitutes approximately 23% of the total contributions to the basin's runoff. The results highlight the strong regional variability in glacier-climate interactions in Central Asia.

How to cite: Saks, T., Pohl, E., Machguth, H., Dehecq, A., Barandun, M., Kenzhebaev, R., Kalashnikova, O., and Hoelzle, M.: Glacier runoff variation since 1981 in the upper Naryn river catchments, Central Tien Shan, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4317,, 2022.