Estimating effective net radiation for a mountainous watershed [Estimation de la radiation nett effective d'un ligne de partage des eaux].

Résumé

The annual curves for net and global solar radiation under clear skies at one point in the Marmot Creek Experimental Watershed in Alberta, Canada, show variations from 55 to 650 ly day/sup -1/ for net radiation, and from 100 to 760 ly day/sup -1/ for global radiation. A factor to convert measured net radiation at the point to a basin average of effective net radiation is obtained by comparing these curves with that for effective clear sky global radiation for the basis, and by considering the ratio of net to global radiation over the various types of vegetation in the basin. This conversion factor varies throughout the year with the elevation of the Sun and the basin albedo, ranging from a maximum of 1.27 in December to a minimum of 0.93 in April, and averaging 1.06 for the year.