RADIATION MODELING IN MOUNTAINOUS TERRAIN - REVIEW AMD STATUS

Advances in the determination of surface net radiation in mountainous terrain have mostly been directed at the computation of shortwave and longwave irradiance. In general, lack of adequate information regarding the surface variables of albedo and thermal exitance have been the major impediments to mapping the net radiation load at the surface. These variables are typically measured during field campaigns at sites of relatively easy access. These point observations are rarely representative of the diversity of the study area. Remotely sensed data have the potential to provide these fluxes with the necessary spatial resolution. Approaches to the determination of the components of the radiation balance in mountainous terrain are reviewed herein. Each component of the radiation balance, namely shortwave and longwave irradiance (i.e., insolation and atmospheric emittance) as well as surface albedo and thermal exitance, is examined. Current limitations towards more precise estimates of the components of the radiation balance are also given. The review concludes with a series of recommendations for future research.