Modelling net radiation in a High Arctic environment using summer field camp data

A model is presented that uses easily obtained twice‐daily field data (cloud‐type, amount, temperature, wind speed at 2 m) to estimate net radiation for horizontal and slope sites in a High Arctic setting. Incoming shortwave radiation is estimated using a cloud‐layer model, sensible and latent heat fluxes are determined using temperature and wind data, and the surface heat flux is obtained as the residual in the energy balance equation. Surface temperature, which is required for longwave radiation, is derived using the force–restore approach. The modelled results compare favourably with field measurements for a cool and wet (1989) and a warm and dry (1990) summer at Hot Weather Creek, Fosheim Peninsula, Ellesmere Island, Northwest Territories, Canada. Significant departures in the results tend to appear during the snowmelt period, suggesting that a better understanding of rapid albedo changes during the snowmelt season is required. A better agreement in 1990 may partly reflect lower errors in incoming shortwave radiation estimates and lower windspeeds, which dampened turbulent transfers. A variable dust coefficient used in the model and the use of cloud data twice daily may partly explain the underestimate of Q* in 1989 and its overestimate in 1990. Overall, the root‐mean‐square error for 1990 was 14–26 per cent when net radiation was averaged over a 5‐day period. The model is useful to geomorphologists, hydrologists and ecologists interested in mapping the spatial pattern of net radiation for slopes, transects or drainage basins in northern environments. © 1997 The Royal Meteorological Society.