Snow-distribution and melt modelling for glaciers in Zackenberg river drainage basin,north-eastern Greenland

A physically based snow-evolution modelling system (SnowModel) that includes four sub-models: MicroMet, EnBal, SnowPack, and SnowTran-3D, was used to simulate eight full-year evolutions of snow accumulation, distribution, sublimation, and surface melt from glaciers in the Zackenberg river drainage basin, in north-east Greenland. Meteorological observations from two meteorological stations were used as model inputs, and spatial snow depth observations, snow melt depletion curves from photographic time lapse, and a satellite image were used for model testing of snow and melt simulations, which differ from previous SnowModel tests methods used on Greenland glaciers. Modelled test-period-average end-of-winter snow water equivalent (SWE) depth for the depletion area differs by a maximum of 14 mm w.eq., or ～6%, more than the observed, and modelled test-period-average snow cover extent differs by a maximum of 5%, or 0·8 km², less than the observed. Furthermore, comparison with a satellite image indicated a 7% discrepancy between observed and modelled snow cover extent for the entire drainage basin. About 18% (31 mm w.eq.) of the solid precipitation was returned to the atmosphere by sublimation. Modelled mean annual snow melt and glacier ice melt for the glaciers in the Zackenberg river drainage basin from 1997 through 2005 (September–August) averaged 207 mm w.eq. year^?1 and 1198 mm w.eq. year^?1, respectively, yielding a total averaging 1405 mm w.eq. year^?1. Total modelled mean annual surface melt varied from 960 mm w.eq. year^?1 to 1989 mm w.eq. year^?1. The surface-melt period started between mid-May and the beginning of June and lasted until mid-September. Annual calculated runoff averaged 1487 mm w.eq. year^?1 (～150 × 10⁶ m³) (1997–2005) with variations from 1031 mm w.eq. year^?1 to 2051 mm w.eq. year^?1. The model simulated a total glacier recession averaging ? 1347 mm w.eq. year^?1 (～136 × 10⁶ m³) (1997–2005), which was almost equal to previous basin average hydrological water balance storage studies ? 244 mm w.eq. year^?1 (～125 × 10⁶ m³) (1997–2003). Copyright © 2007 John Wiley & Sons, Ltd.