Submitted to: Journal of Hydrology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/2/2012
Publication Date: 8/1/2013
Citation: Luo, Y., Arnold, J.G., Liu, S., Wang, X., Chen, X. 2013. Inclusion of glacier processes for distributed hydrological modeling at basin scale with application to a watershed in Tianshan Mountains, northwest China. Journal of Hydrology. 477(16):72-85. Interpretive Summary: There is recent evidence that glaciers are retreating in many areas of the world. Also, flow from snow and glacier melt supply water for several important crop production areas under irrigation in the U.S. and across the globe. In this study, we developed algorithms for glacier melt, sublimation, accumulation, retreat, and mass balance. The glacier module was incorporated into the Soil and Water Assessment Tool (SWAT) and applied to the Manas River Basin in the Tianshan Mountains in northwest China. Model results indicate that glacier area decreased over 10% during 1961-1999 which is comparable to recorded retreat of other glaciers. The impact of temperature and precipitation changes were also studied, showing that glacial retreat is more sensitive to potential changes to temperature. The model developed in this study provides a tool to determine glacier dynamics and impact of potential climate change on glacial retreat and ultimately the impact on irrigated agriculture.
Technical Abstract: In this paper we proposed: (1) an algorithm of glacier melt, sublimation/evaporation, accumulation, mass balance and retreat; (2) a dynamic Hydrological Response Unit approach for incorporating the algorithm into the Soil and Water Assessment Tool (SWAT) model; and (3) simulated the transient glacier retreat and its impacts on stream flow at basin scale. Application of the enhanced SWAT model in the Manas River Basin (MRB) in the Tianshan Mountains in northwest China, shows that the approach is viable as evidenced by a Nash–Sutcliff efficiency of 0.65 and a percent bias of -3.7% for daily stream flow and water balance, respectively. The results indicate 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 stream flow, although glacier area accounts for only 14% of the catchment drainage area in the MRB. 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 results indicate 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.