Projection of Future Frequency of Severe and Extreme Droughts over Iran Country

Abstract

Abstract Drought is one of the most destructive environmental hazards posing negative economic and social consequences. The country of Iran, which is located in the dry and semi-arid belt, is involved in many damages caused by drought every year, which makes it necessary to investigate. In this study, an attempt was made to investigate the frequency (number of occurrences) of severe and extreme droughts in the future. At first, the output of 10 climate models of the fifth report of the Intergovernmental Panel on Climate Change (IPCC) was combined using a weighting method, taking into account the model error, being used as a scenario file for the statistical downscaling of climate data in the LARS-WG. In the following, using SPI index, the frequency of severe and extreme drought was calculated. Examining the frequency of drought in different groups showed that the number of severe and extreme drought events will increase in most of them. The results showed that most groups will experience a significant increase in the frequency of extreme droughts compared to severe droughts. The percentage of changes in the number of extreme drought events was observed in most groups above 60%. Group 4 stations, which receive the highest amount of annual rainfall, along with group 3, suffered the highest increase in the frequency of extreme droughts. Considering that these areas are the main agricultural poles in the country, increasing the frequency of extreme drought can create harmful economic, social and environmental consequences.