A new operational model for satellite-derived irradiances: Description and validation

We present a new simple model capable of exploiting geostationary satellite visible images for the production of site/time-specific global and direct irradiances The new model features new clear sky global and direct irradiance functions, a new cloud-index-to-irradiance index function, and a new global-to-direct-irradiance conversion model. The model can also exploit operationally available snow cover resource data, while deriving local ground specular reflectance characteristics from the stream of incoming satellite data. Validation against 10 US locations representing a wide range of climatic environments indicates that model performance is systematically improved, compared to current visible-channel-based modeling practice. (C) 2003 Elsevier Science Ltd. All rights reserved.