An Estimate of the Heat Balance of a Valley and Hill Station in Central Alaska

Abstract

The heat balance was estimated and climatic elements were compared for two stations in the Fairbanks area on a year-round basis, the first study of this kind carried out in the interior of Alaska. Although the stations were situated near to each other (within 5 km and 200 m altitude), great differences were observed. For the valley station the heat source is mainly radiation with 61 cal cm?2 for an average day of the year August 1966 to July 1967, and to a smaller extent, sensible heat flux (17 cal cm?2). Most of this energy is needed for evaporation (?74 cal cm?2). The heat flow in the soil is about zero over the year and the actual value of ?4 cal cm?2 was mainly used for melting of the snow cover. For the hill station the heat fluxes are generally smaller. The only source is the radiation balance (24 cal cm?2), which is only 40% of the value found for the valley station. The latent heat flux is much smaller (?19 cal cm?2), and the surface temperature on the hill is higher. The sensible heat flux is slightly negative (?2 cal cm?2), meaning that the air will be warmed by the surface only slightly for an average day over a year in contrast to the valley station. This higher surface temperature also raises the outgoing longwave radiation, and can explain partially the less positive radiation balance for the hill station. The heat flux in the soil is again near zero and the value of ?3 cal cm?2 represents the energy needed to melt the snow cover. The agreement of the radiation balance with long-term means calculated by Gavrilova was found to be satisfactory.