عنوان مقاله [English]
Today, drought indices as the appropriate tools for management actions and exposure to drought, has been widely used around the world. Application of some indicators, particularly the physical-based indicators such as Palmer drought severity index (PDSI) in a new area may need to be calibrated first. The aim of this study is to calibrate Palmer Drought Severity Index (PDSI) under the climatic conditions of arid and semiarid regions of West and South West of Iran and to compare that with the original version of the Palmer Index. Required input data are values of the monthly mean temperature and monthly total precipitation from nine synoptic stations in West and South-West of Iran were collected for the period 1966-2005. The results showed although does not have much difference between the main coefficients of calibrated Palmer index and the original version of that, but due to the large difference between the monthly weighting factors between the calibrated version of the main series of calibrated version and initial, there are significant differences. In addition, it was found that the equations of severity - duration of drought phenomena and frequency of different classes of drought and non-drought, there are significant difference between the initial version and calibrated versions in the selected stations.