Assessment of Geostatistical Methods for Spatial Analysis of SPI and EDI Drought Indices

Abstract

Abstract: Drought monitoring is a fundamental ingredient of drought risk management. It is normally performed using various drought indices that are effectively continuous functions of rainfall and other hydrometeorological variables. In many instances drought indices used for monitoring purposes. However, these indices are calculated at sites and it is required to estimate the spatial distribution of drought in the forms of maps. Geostatistical methods allow the interpolation of spatially referenced data. They allow the prediction of values for arbitrary points in the area of interest. In this research, several geostatistical methods including Ordinary Kriging,Inverse Distance Weighted and Thin Palte Smoothing Splinewere assessed for the derivation of maps of drought indices at 27 climatic stations in the Boushehr province of Iran. The results indicated that IDW method with the power of two is more appropriate for spatial analysis of SPI index and Ordinary Kriging method is more appropriate for spatial analysis of EDI index.