Degree-day modelling of the surface mass balance of Urumqi Glacier No. 1, Tian Shan, China
E. Huintjes1, H. Li2, T. Sauter1, Z. Li2, and C. Schneider11Department of Geography, RWTH Aachen University, Wuellnerstr. 5b, 52056 Aachen, Germany 2Cold and Arid Regions Environment and Engineering Research Institute, CAS, 320 Donggang West Rd., 730000 Lanzhou, China
Received: 23 Feb 2010 – Accepted for review: 01 Mar 2010 – Discussion started: 03 Mar 2010
Abstract. A distributed temperature-index melt model including potential shortwave radiation is used to calculate annual mean surface mass balance and the spatial distribution of melt rates on the east branch of Urumqi Glacier No. 1, north-western China. The lack of continuous datasets at higher temporal resolution for various climate variables suggests the application of a degree-day model with only few required input variables. The model is calibrated for a six day period in July 2007, for which daily mass balance measurements and meteorological data are available. Based on point measurements of mass balance, parameter values are optimised running a constrained multivariable function using the simplex search method. To evaluate the model performance, annual mass balances for the period 1987/88–2004/05 are calculated using NCEP/NCAR-Reanalysis data. The modelled values fit the observed mass balance with a correlation of 0.98 and an RMSE of 332 mm w.e. Furthermore, the calculated spatial distribution of melt rates shows an improvement in small-scale variations compared to the simple degree-day approach.
Huintjes, E., Li, H., Sauter, T., Li, Z., and Schneider, C.: Degree-day modelling of the surface mass balance of Urumqi Glacier No. 1, Tian Shan, China, The Cryosphere Discuss., 4, 207-232, doi:10.5194/tcd-4-207-2010, 2010.