ESTIMATION OF GLACIER MELT IN THE TROPICAL ZONGO WITH AN ENHANCED TEMPERATURE-INDEX MODEL

Abstract

An enhanced temperature-index model including albedo and shortwave radiation has been applied to the tropical Zongo glacier. The model satisfactorily simulated the daily discharges and their seasonal variations with an efficiency of 0.71 (Nash-Sutcliffe). The energy balance analysis revealed that three factors mainly control melt on this glacier: incoming shortwave radiation, incoming longwave radiation and sensible heat flux. Accordingly, the model differentiates between temperature-dependent and temperature-independent components moving towards a more physically based but still simple model. Modelling was improved with respect to the traditional degree-day method in the wet season characterized by simultaneous accumulation and strong melting while capturing the low melt rates found in the dry season. However the model missed some peaks in discharge due to the underestimation of precipitation at the low elevation meteorological station.