Inclusion of Glacier Processes for Distributed Hydrological Modeling at Basin Scale with Application to a Watershed in Tianshan Mountains

Glaciers are sensitive to global climatic changes and are the most visible indicators of global change. Climate warming will cause accelerated glacier retreat, which will result in decreased summer streamflow. Changes in runoff due to glacier retreat is concerning, especially in areas where glacier runoff is a major source of water for agricultural, industrial, and municipal uses. Hydrological investigations of glaciers are thus necessary for these watersheds.

Physically-based, distributed hydrological models are currently available and may be used to evaluate distributed snow, ice melting, and runoff formation in glaciered watersheds in a more detailed way. The Soil Water Assessment Tool (SWAT), a basin-scale, continuous-time, physically based, distributed model, is capable of continuous simulation over long time periods. SWAT has been used in a wide range of climatic, topographic, soil, and management conditions around the world to investigate a broad range of hydrological and environmental topics, including cases of snow hydrology studies.

Therefore, Prof. LUO Yi et al. applied the SWAT model in the Manas River Basin in the Tianshan Mountains, China. The aims of this study are to develop a glacier processes module that the glacier processes can be simulated in a distributed way at the watershed scale, evaluate the glacier module performance in a glaciered watershed, and discuss the glacier-melt-induced streamflow process that is related to the precipitation and temperature.

The result showed that the glacier area decreased by 11% during the simulation period from 1961 to 1999, which is within the range of records from other glaciers. On average, glacier melt contributed 25% to streamflow, although glacier area accounts for only 14% of the catchment drainage area in the Manas River Basin. Glacier melt was positively correlated to temperature change (R²=0.70, statistical significance P<0.001) and negatively correlated to precipitation (R²=0.20, statistical significance P<0.005).

The result indicated that glacier melt was more sensitive to temperature change than to precipitation change, implying that modeling the effects of climate change with increasing temperatures and decreasing precipitation should be further studied. The finding was published in Journal of Hydrology in January 2013, 477: 72-85.

Contact:

Prof. LUO Yi

Email: luoyi.cas@hotmail.com