A Coupled Glacier-Hydrology Model and Its Application in Eastern Pamir

Abstract

An energy-balance glacier-melt scheme was coupled with the Variable Infiltration Capacity hydrology model (VIC-glacier). The coupled model was setup at 30 m × 30 m grids and applied in the Muji basin in eastern Pamir. The model was validated with field measurements of albedo, glacier mass balance, and river runoff. The VIC-glacier model showed a good correspondence with the observations in incoming shortwave radiation and albedo, with R 2 of 0.70 and 0.32, respectively, during August–October 2012. Simulated glacier mass balance exhibited overall good agreements with the observations in ablation seasons, with R 2 of 0.89 and root-mean-square error of 162.12 mm w.e. during 2011–2015. The model also reproduced discharge records, with R 2 of 0.70–0.84, Nash-Sutcliffe efficiency of 0.56–0.81, root-mean-square error of 0.29–0.45 m 3 /s, and negative relative error of 13.73–18.76% in melt seasons of 2014–2015. The glaciers in Muji basin had a low mean net radiation of 40 W/m 2 , large negative latent heat fluxes of −32 W/m 2 , and low melt energy of −21 W/m 2 in ablation seasons, resembling the energy partitioning generally found in continental climates. About 60% of the positive energy supply was consumed by latent heat fluxes on the glaciers in Muji basin, while only about 40% of the positive energy supply was used for melting. Glaciers in the Muji basin experienced a mass balance of −812.18 mm over 2011–2015, corresponding to a water release of 4.42 × 10 6  m 3 .The VIC-glacier model has a good potential of broader utility for the large basins with limited meteorological observations.