| Abstrakt: |
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). Research Highlights: 1. The study focuses on monitoring and projecting spatiotemporal changes in extreme precipitation indices over Iran for historic (1980 to 2006), near future (2021-2050), and far future (2071-2100) time periods. 2. From 1980 to 2006, MERRA2 reanalysis precipitation data show a strong spatial correlation with monthly observational data, and total precipitation shows negative significant trends in the northwest and positive significant trends in the north. 2. From 1980 to 2006, MERRA2 reanalysis precipitation data show a strong spatial correlation with monthly observational data, and total precipitation shows negative significant trends in the northwest and positive significant trends in the north. 3. For projecting extreme precipitation, four CORDEX-WAS models based on two RCPs (RCP4.5 and RCP8.5) are used. 4. A precise plane is required to deal with precipitation reduction and increased dry spells in the near and far future. [ABSTRACT FROM AUTHOR] |
