A complete century series of temperature is the basis of climate change analysis. The local century temperature changes have general characteristics, also retain some differences. Based on temperature observation data at Wuhu station of Anhui Province during 1880-1937 and 1952-2020 and CRU (Climatic Research Unit) grid data of University of East Anglia during 1901-2020, the test and correction to observation data of temperature were conducted to obtain high quality data. And on this basis that the time series of temperature from 1880 to 2020 at Wuhu station was constructed by using the multiple stepwise regression method, its decadal characteristics were analyzed. The results show that the quality of monthly mean temperature at Wuhu station from 1880 to 1937 was improved after the difference and homogeneity corrections. Two temperature series were constructed by using the stepwise regression analysis based on CRU grid data during 1901-2020 and station observation data during 1901-1937 and 1953-2020, and the interpolated temperature by their average value could display perfectly the variation characteristic of monthly mean temperature at Wuhu station during 1938-1951. The spring, summer and winter temperature increased significantly at Wuhu station in past 140 years, and the increasing rate of spring temperature was the maximum, followed by summer and winter, while the warming in autumn wasn’t significant. The decadal characteristic of coldness and warmness alternation was obvious in each season from 1880 to 2020, but the warming stalled in recent 20 years. In addition, there were 40-50 a and 20-30 a periodic oscillations of mean temperature.

Based on conventional observation data, regional automatic station data of Hunan Province, NCEP reanalysis data and Changde Doppler radar data, the mesoscale characteristic of extreme rainstorms occurring repeatedly in the north of Hunan Province from 8 to 15 August 2016 affected by several easterly waves was analyzed comprehensively. The effect of the Wuling mountains topography on rainfall increase was further verified by WRF-ARW mesoscale numerical experiments. The results are as follows: (1) After the typhoon 1604 landing at Shenzhen of Guangdong Province and moving northwestward and the typhoon 1605 moving northward, the western Pacific subtropical high rapidly extended westward and controled east China and coastal areas. At this time, the easterly wave disturbance at the bottom of the subtropical high provided the circulation background for extreme rainstorms. (2) The non-uniform heating near the ground provided sufficient thermal instability for the strong convection near the easterly wave trough, the surface mesoscale convergence line played an important role in triggering and strengthening the convection. (3) During the eastward movement of the boundary-layer warm moist air, a deep mesoscale vortex formed in east side of the Wuling mountains, which was the main reasons for the extreme rainstorm formation. (4) The topographic numerical sensitivity experiment further verified that the existence of the Wuling mountains was beneficial to the development and maintenance of strong convection on the east side of the mountain under the guidance of the easterly wind flow.