A spreadsheet-based (Microsoft Excel) point surface energy balance model for glacier and snow melt studies

This paper describes a point surface energy balance model which runs within the Microsoft Excel spreadsheet package. The study incorporates a large am ount of previous energy balance work and presents it in a useable form. The core model calculates the net shortwave and longwave radiation fluxes, the turbulent sensible and latent heat fluxes and the surface melt rate at a p oint on a melting ice or snow surface, from hourly inputs of incoming short wave radiation, vapour pressure, air temperature and wind speed data. The l atitude, longitude, slope angle, aspect, elevation, local temperature lapse rate, albedo and aerodynamic roughness of the study site, and the elevatio n of the meteorological station, can all be specified in the model. An outp ut file containing the hourly and daily rates, and the totals of the energy fluxes is generated. The main advantages of the model are: first, that it requires only a PC or laptop computer running standard Microsoft Windows so ftware, enabling it to be used at a desktop or in the field; and second, th at it can be adapted quickly to different sites, meteorological data format s and other application requirements. Model calculations are compared with measured surface melt rates at five points on Haut Glacier d'Arolla, Switze rland, over a 115 day ablation period. Allowing for differences in shading between the meteorological station and the glacier, the root mean square er ror of the calculated melt rates is 2.0 mm day(-1) water equivalent melt (m ean error +1.2 mm day(-1)), for measured melt rates in the range 23 to 42 m m day(-1) water equivalent melt. Copyright (C) 2000 John Wiley & Sons, Ltd.