| Abstract | Observations were made with two commerically available radiometers on the net radiation absorbed by an exposed snow surface during the snow-melt period at Ottawa, Ontario, Canada. Although a considerable difference was found between the net radiation recorded by the two instruments, no decision could be made as to their relative accuracy. Using the mean of the values of net radiation obtained for each observation period, the components of the energy balance at the surface were calculated. Although it was difficult to assess the accuracy of the estimates obtained for these components, these calculations indicated that evaporation during the observation periods was a large percentage of the net radiation, and amounted to between 20 and 25 per cent of the snow that was dissipated. During 1959 and 1960, the Snow and Ice Section of the Division of Building Research, National Research Council of Canada, has been making observations on the radiation at various surfaces, including snow. The purpose of these observations has been two-fold: 1. to evaluate under field conditions various commercially available instruments for measuring net radiation, and 2. to determine the net radiation as one component of the total energy balance at the surface. The purpose of this paper is to explain some of the difficulties that were encountered in the use of two commercially available net radiometers, to compare observations made with them, and to present the components of the heat balance calculated from the observations made during the snow-melt period at Ottawa. |
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