Retrieval of high mountain precipitation and temperature for a quantitative assessment of the hydrologic flow regime in the Upper Yarkand River basin in the Karakoram

Abstract:

Glacier meltwater provides an important contribution to river runoff and strongly affects the flow regime of many mountainous drainages, particularly in arid and semi-arid regions. With the retreat of glaciers as currently observed in most mountain regions, understanding the quantity and timing of the meltwater is important for water resources management downstream. Hydrological model is a useful tool for estimating the present and future runoff response to a changing climate in the high-elevation and glacierized basins, yet the scarcity of meteorological observations restricts the predictive skill and accuracy of the hydrological models. In this work, 54 years (1960-2013) daily meteorological forcing data at 5km×5km spatial resolution were retrieved for the upper Yarkand river basin (5×10⁴km²), a glacierized basin (11%) with high elevations in the Karakoram. The data construction was based on precipitation gradient (PG) and temperature laps rates (TLRs) observations from ten Rain Gauges and thirteen Temperature Probes installed in the basin during 2013-2014, together with the data from four national official meteorological stations. The derived forcing data was used to force the Variable Infiltration Capacity (VIC) distributed land surface hydrological model linked with a degree-day glacier-melt model over the entire basin for 1960-2013. The specific aims are to: 1) characterize the precipitation and temperature variability in this high mountain basin, 2) quantify the contributions of rainfall, snowmelt, and glacier melt to the upper Yarkand river basin.