Monitoring and prediction of drought by Markov chain model based on SPI and new index in Isfahan

Abstract

Drought evaluation and associated prediction are essential for water resource management. Most of previous studies analysed and predicted drought pattern in Isfahan based on the standardised precipitation index (SPI). Due to the high evapotranspiration in Isfahan, the SPI index, which is based on precipitation alone may not be sufficient to monitor and estimate drought pattern. So, it is vital to analyse and predict drought phenomenon at this region based on the new index (standardised precipitation-evaporation index - SPEI) that considers potential evapotranspiration in addition to the precipitation. Hence drought analysis is performed based on SPI and SPEI in Isfahan. The results indicate that there is some difference between two indices. Finally, SPEI and the Markov chain model are applied to predict the drought patterns in a 30 years period in the long-term future. It is predicted that the percentage of aridity state will increase comparison with the past decade.