In this paper the authors present an algorithm that combines solar rad
iation fields derived from Geostationary Operational Environmental Sat
ellite (GOES) observations with digital elevation data to produce topo
graphically varying insolation fields at fine grid spacing. Cloud-modu
lated irradiances are obtained using hourly 8-km resolution GOES obser
vations. These irradiances are then spatially integrated to the grid s
pacing of the digital elevation data. The integration accounts for unc
ertainties in satellite navigation, the limited sensor resolution rela
tive to the hemispheric field of view of a terrain element, and the mi
smatch between the instantaneous fluxes estimated by GOES observations
and the time-integrated quantities typically used in distributed mode
ling, such as hourly fluxes. The integrated fields are partitioned int
o direct and diffuse components and then adjusted for the effects of e
levation. Lastly, other topographic effects, such as slope orientation
, shadowing, sky obstruction, and terrain reflectance are modeled usin
g fields derived from the digital elevation data. The final product is
a map of solar radiation that marries coarse-scale variability in ins
olation caused by clouds with the finescale variability caused by topo
graphy. The authors demonstrate the technique for a portion of the Roc
ky Mountains, using a 90-m digital terrain model covering over 1 degre
es x 1 degrees of latitude and longitude. Lastly, assumptions, limitat
ions, and sources of error in data and algorithms are discussed.