Keywords: meteorological processor, sensible and latent heat fluxes, solar radiation, winter conditions
Meteorological pre-processing of incoming solar radiation and heat flux over a sparse boreal forest at a northern site during winter conditions
Measurements from Northern Finland on radiation and turbulent fluxes over a sparse boreal forest with snow-covered ground were analysed. The measurements represent harsh winter conditions characterised by low sun angles. The absorption of incoming solar radiation in clear skies (turbidity) was found to be a strong function of the solar elevation. At low solar elevation angles, commonly used expressions for turbidity did not fit the measurements well. A simple energy balance type met-processor performed well during daytime, but it was not satisfactory during night time. Simplifications and possible improvements in the energy balance model are discussed.