An assessment of Iran's seasonal temperature probability distribution variations in the future decades

Abstract

Global warming in arid and semi-arid regions such as Iran is characterized by water scarcity and drought. In this paper, climate change impact on seasonal maximum and minimum temperature was done. To do so, three global climate models including CANESM2, GFDL-ESM2M, and HADGEM2-ES were used to simulate future climate change across Iran. SDSM model was used to downscale the CANESM2 model data. The data of GFDL-ESM2M and HADGEM2-ES models were downloaded from CORDEX database. In the present paper, the time period of 1976–2005 was considered as the base period and the time scales of 2011–2040, 2041–2070, and 2071–2099 as the future periods. The RCP2.6, RCP4.5, and RCP8.5 scenarios were chosen to future projection of minimum and maximum temperature. Taylor diagram was used to model evaluation. The results showed that the performance of SDSM model in minimum and maximum temperature downscaling in the base period is better than CORDEX database. One reason could be the smaller number of stations selected compared to CORDEX grid points. Results showed the highest positive anomalies of average maximum and minimum temperature compared to the base period studied (1976–2005), related to time period 2071–2099 and RCP8.5 by 6.69 and 6.61°C, respectively. The results showed that the maximum temperature will increase between 0.82 and 3.7°C on average depending on the season, time, and type of scenario. This value is in the range of 0.4–3.87°C for the minimum temperature. Results showed that hot days will increase. Results also showed that cold nights of winter in the coming decades will be warmer than the base period. The results also indicate that the frequency distributions of minimum and maximum temperatures in the future decades will shift to warmer temperatures in response to global warming.