A CORRECTION FOR THE NET RADIOMETER REFLECTION ERROR AND ANALYSIS OF MEASURED NET RADIATION VALUES FOR CANADA.

A correction factor is developed to convert measured net radiation values obtained from a net radiometer to the net radiation for a lake based on the reflectance difference of water and polyethylene surfaces. Formulae are presented to calculate the reflectance of a polyethylene and water surface given the angle of incidence of the solar beam date and time. Daily, monthly, and annual values of measured net radiation were calculated for four central Canadian sites for the period 1960 through 1963. These values are compared with the calculated estimates of Simpson, London, and Budyko, and with measured values recorded by the Meteorological Branch, Department of Transport of Canada for five other Canadian sites. The measured net radiation gradient is directed normal to the tree line, and stations in areas of similar plant communities report similar net radiation regimes. Relationships between net radiation and mean daily cloud cover are investigated. The technique of Fourier analysis is used to study the asymmetry of the annual net radiation curves.