Projecting spatiotemporal changes of precipitation over Iran using CORDEX regional climate models until 2100

One of the most important aspects of climate change is alterations in the amount and characteristics of precipitation. The present study intended to project precipitation changes over Iran based on the regional models of the CORDEX project under two scenarios (namely, RCP4.5 and RCP8.5). For this purpose, six indices, including maximum 1-day precipitation, simple precipitation intensity index, maximum length of dry spell, annual count of days when PRCP >= 10 mm, annual count of days when PRCP >= 1 mm, and annual total precipitation in wet days, were extracted. MERRA2 reanalysis precipitation data, highly correlated with observation data from 48 weather stations all over the country, were used for the 1980-2006 time period to assess the CORDEX project outputs. The results were presented in three different time periods, including the base period (1980-2006), the near future (2021-2050), and the far future (2071-2100). The results of the analyses indicated that four indices, namely the maximum 1-day precipitation, the annual count of days when PRCP >= 1 mm, the annual count of days when PRCP >= 10 mm, and the annual total precipitation in wet days, demonstrated a decrease in precipitation and an increase in dry spells all over the country except for the east and the southeast regions where these indices will increase compared to the base period (except for the maximum length of the dry spell).