Technical Report Trend Analysis of Meteorological Drought Characteristics in Hamedan Province

The purpose of this study is analyzing the trend of drought characteristics in Hamedan Province In this regard, the corrected standardized precipitation index (SPImod) was calculated based on the monthly precipitation data from 11 synoptic and rain gauge stations during the period of 1985-2013. Drought characteristics, including severity, duration and interarrival time were defined and extracted based on the SPImod. The Sen’s estimator was used to estimate the slopes of trend lines. The results show that in most of the stations, drought duration had a non-significant decreasing trend, while the drought severity in over half of the stations had a non-significant decreasing trend. The drought interarrival time witnessed a non-significant decreasing trend in all of the stations, except at the Varayeneh station, which experienced a significant increasing trend at 1%. The monthly rainfall experienced a non-significant increasing trend in most of the stations except Keyto which experienced a non-significant decreasing trend.