UC Santa Barbara

A theoretically based model accurtely calculates incoming longwave radiation under clear sky conditions in a remote alpine area. Data requirements are relatively simple and because the model is theoretically based it can be widely applied. The model calculates atmospheric radiation using a form of Brutsaert's method that is adjusted for variations in air pressure and radiation from adjacent slopes. Tests of both point and areal applications indicate that the method gives reliable results. When applied as a segment of an energy balance snowmelt model, the model provides information on energy exchange in an alpine environment and improved snowmelt runoff prediction. Radiation from cloud cover and canopy cover can be more easily isolated by using the model to account for clear sky radiation. It is possible that it can also calibrate atmospheric effects in thermal satellite data, thus enhancing the possibilities for using satellite radiometry in alpine areas. © 1979 Springer-Verlag.