Climate of the Greenland ice sheet using a high-resolution climate model – Part 1: Evaluation
1Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, The Netherlands
2Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, The Netherlands
3Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
4Department of Geography, Byrd Polar Research Center, Ohio State University, Columbia, Ohio, USA
5Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
Abstract. A simulation of 51 years (1957–2008) has been performed over Greenland using the regional atmospheric climate model (RACMO2/GR) at a horizontal grid spacing of 11 km and forced by ECMWF re-analysis products. To better represent processes affecting ice sheet surface mass balance, such as meltwater refreezing and penetration, an additional snow/ice surface module has been developed and implemented into the surface part of the climate model. The temporal evolution and climatology of the model is evaluated with in situ coastal and ice sheet atmospheric measurements of near-surface variables and surface energy balance components. The bias for the near-surface air temperature (−0.8 °C), specific humidity (0.1 g kg−1), wind speed (0.3 m s−1) as well as for radiative (2.5 W m−2 for net radiation) and turbulent heat fluxes shows that the model is in good accordance with available observations on and around the ice sheet. The modelled surface energy budget underestimates the downward longwave radiation and overestimates the sensible heat flux. Due to their compensating effect, the averaged 2 m temperature bias is small and the katabatic wind circulation well captured by the model.