Assessment of aridity index in Iran

This paper discusses spatial and temporal variability of climate parameters of Zayandeh Rood Basin (Z.R.B.) in Iran. Standard climate parameters are precipitation, temperature, evaporation and wind (during 1951-2005). Objective of this research was to evaluate coefficients of drought index in the study area by calculating coefficients of drought and classified hazard map by measuring aridity parameters in form of the Kriging map. This paper presents a classified aridity map. The classification method is based on such main parameters as precipitation, wind, evaporation and temperature. Each parameter includes a sub-indicator with statistical data and vector map. The sum of score parameters was estimated by using a weighted average. Construction of missing data was tested by regression and homogenous method. Result shows the very high classes of aridity in East and North of the basin and very low class in West, and North-West. The final map shows level of aridity index in the study area. In this study, Arc GIS 9.3 was used to analyse the vector.