Investigation of drought and wet season in Chahbahar city using SPI index

A large part of our country has an arid and semi-arid climate due to being located in the desert belt of the world, and because of this it receives little rainfall (one third of the world average rainfall), which also has severe rainfall in different years. Drought is a phenomenon that occurs at least once a year as a result of reduced rainfall in different parts of the world, and if agriculture cannot resist this phenomenon, famine will occur. Numerous indicators are used to monitor drought as indicators of drought around the world. In this study, SPI index has been used to study drought and wetlands in Chahbahar city. To conduct this research and with the aim of analyzing precipitation and determining dry and wet years, monthly precipitation data of Chahbahar Synoptic Meteorological Station in a period of 34 years (2018-1985) have been used. The results of this study show that in 6 months of the year, from December to the end of May, most years of drought have occurred and the drought situation is mild, mild. Also, in 6 months of the year, from June to the end of November, the situation of Chahbahar city is in normal conditions and no drought has occurred in this part of the year. The results also show that the number of wetlands in Chahbahar is less than droughts, but unlike droughts, they occur in all months of the year except May, and January with 10 wet years, 13 drought years and 11 The year of normal conditions is the most volatile month of the year. Also, 1997, 2007 and 2008 were the wettest years during the period under review.