Based on the data of daily precipitation and mean temperature from 80 national meteorological stations in Anhui Province from 1961 to 2022, the processes of regional extreme climate events are identified according to the objective identification technique for regional extreme events. Average intensity, duration and average influence range are further extracted, which are applied to establish comprehensive intensity assessment model, and then regional high temperature and drought processes in 2022 are comprehensively evaluated. The results show that the average temperature in Anhui Province in the summer of 2022 is 2.2 ℃ higher than normal, which is the highest in the same period since 1961.The precipitation in 2022 is 40% less than normal, which is the fourth lowest since 1961. Persistent high temperature and little rainfall led to continuous severe drought in summer and fall in the south of the Huaihe River in Anhui Province. There are six regional high temperature processes in the summer of 2022, and the high temperature process from August 1 to 23, 2022 has reached the "super strong" level, which rank the fourth in history and is inferior to the high temperature processes in 1966, 1967 and 2013. However, the annual cumulative comprehensive intensity of high temperature in 2022 reached 4496, which is the highest since 1961.Two regional drought processes occurred in the summer and autumn of 2022. Compared with the nine strongest regional drought processes in summer and autumn since 1961, by the end of September 30, 2022 the regional drought process since July 28 has lasted 65 days, and the intensity level is "super strong", which is inferior to the processes in 1966, 1967, 1978 and 2019.

Based on the meteorological observation data at seven national stations in Chuzhou of Anhui Province from 1961 to 2019 and the observation data in growth periods and yield per unit area of wheat from 1980 to 2019, the characteristics of meteorological drought and flood in Chuzhou and its impact on wheat yield were discussed and analyzed by using the multi-time-scale SPEI. The results show that the monthly and seasonal variation characteristics of SPEI were obvious in Chuzhou, and the astringency of SPEI in each month of winter was the strongest, while the dispersion of SPEI in each month of summer was the biggest. The climate characteristic of drought in spring and flood in summer was obvious in Chuzhou. The continuous drought from spring to summer was the most serious seasonal continuous drought in Chuzhou, and the continuous flood from spring to summer was the most serious seasonal continuous flood in the whole year. There was a trend of drought in spring since 2000 in Chuzhou, and the climate in summer and winter became wet after the 1990s, especially in winter, while the trend of dry and wet in autumn wasn’t significant, but there was a slight humidifying trend after 2009. The correlation between SPEI3 in March and wheat climate yield was the most significant, and there was parabola relationship with negative quadratic coefficient between them. When the value of SPEI3 in March was greater than 0.81 or less than -1.93, the yield of wheat was likely to reduce highly.

Based on daily climatic elements data simulated by five global circulation models (GCMs) in the coupled model intercomparison project phase 5 (CMIP5) under three representative concentration pathways (RCPs), daily mean temperature, precipitation and solar total radiation from 50 weather stations, and growth period and per unit yield of single-season rice in the south of the Huaihe River of Anhui Province, the climate changes during the growth period of single-season rice in the south of the Huaihe River of Anhui Province were estimated in the 21st century. And on this basis, the climatic productivity potential (YCPP) of single-season rice and its response to climate changes during the growth period were estimated in near term (2018-2039), middle term (2040-2069), and long term (2070-2099) by using the productivity decay method. The results are as follows: (1) The simulation ability of five GCMs to temperature and precipitation in the south of the Huaihe River of Anhui Province was well, and the simulation effect of temperature was better than that of precipitation. (2) The different growth stages of single-season rice in the south of the Huaihe River would be ahead under different RCPs scenarios in the 21st century, and the whole growth period would shorten. The temperature during whole growth stage of single-season rice would continue to increase under different climate scenarios in the future, and the warming rate in the north would be higher than that in the south, especially under RCP8.5 scenario. The precipitation would present a fluctuating change as a whole, but it would increase obviously in southern region, while the solar total radiation would decrease significantly in the future. (3) The estimated climatic productivity potential of single-season rice under different RCPs scenarios would decrease significantly in the 21st century compared with the baseline period, especially in long period. (4) The climatic productivity potential of single-season rice would be negative and positive correlated significantly with mean temperature and precipitation during whole growth stage from 2018 to 2099, respectively, and the negative effect of climate warming on climatic productivity potential would be prominent. In conclusion, the climate change in the future would not be conducive to the improvement of climatic potential productivity of single-season rice in the south of the Huaihe River of Anhui Province.