Developing a climate model for Iran using GIS

In order to develop a climate model for Iran, monthly mean climatic variables from 117 synoptic stations were obtained from the Iranian Meteorological Organisation. These variables were reduced to six orthogonal factors using factor analysis. The stations were then divided into six groups using cluster analysis. Within each climatic group, the lowest and highest thresholds for each factor were identified. The factor scores of the stations within each factor were interpolated across the country applying Inverse Squared Distance Weight in the ArcGIS environment. Based on the factor scores, six conditional functions were defined to allocate each pixel to a region. In order to simplify the models, one index variable was substituted for each factor. Then, through Discriminant Analysis, the constants and coefficients of the models were determined. The final models were evaluated against some examples, one of which, Yazd, was demonstrated fully.