ABSTRACT
Distributing modeling is the emerging technique to analyze the spatial and temporal variability of solar radiation, particularly over the rugged terrain. The knowledge of the solar radiation distribution over time and space is becoming more and more vital due to the growing interest in solar energy utilization [1]. Incoming direct solar radiation (DSR) is the main contributor of incoming solar radiation to earth because it adds the most to the energy balance and also the other components depend on it [2]. The understanding of the DSR distribution both temporally and spatially is one of the imperative needs for understanding of thermody-
namic or dynamic processes involved in energy exchange, which can be applicable in agricultural planning [3], architectural design [4], and engineering [5]. Solar radiation energy exchange also plays a key role in surface water circulation [6]. For these reasons, analysis of the incoming solar radiation distribution in Pakistan is important. As seasonal and latitudinal variations are well understood and described; only recent studies analyzed topographic variability in diurnal and seasonal radiation patterns over a region or locally [7].
