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Based on the daily precipitation data of 545 meteorological stations in China from 1961 to 2016, the spatial-temporal variation characteristics of rainstorm rainfall and rainy days in different months of China were diagnosed from three aspects: climatic characteristics, variation trend and interannual variation. The results showed that: (1) Rainstorm rainfall and rainy days in different months of China from 1961 to 2016 had similar spatial characteristics in corresponding months. From January to July, the high-value areas of rainstorm rainfall and rainy days gradually expanded from southeast coast to northwest inland, but mainly distributed in the east area of Hu Huanyong Line. From August to December, it shrank from northwest to southeast coastal areas. Rainstorm rainfall and rainy days were less distributed in different months in the west area of Hu Huanyong Line; (2) From 1961 to 2016, the spatial-temporal variation characteristics of rainstorm rainfall in different months in China were basically consistent with that of rainy days. May to August was the most significant month for the variation trend of rainstorm rainfall and rainy days in China. It mainly distributed in the southeast monsoon area, and was mainly increasing trend. The trend of rainstorm rainfall and rainy days in northwest China changed slightly in different months; (3) The interannual variability of rainstorm rainfall in different months in China from 1961 to 2016 was similar to that of rainy days. The fluctuation characteristics from April to October were larger in the northern region. The southern region fluctuated greatly from November to December in January to March. With the development of the month, the high-value areas with large daily fluctuations of rainstorm rainfall and rainy days gradually expanded from southeast to northwest, northeast and southwest, and the fluctuations in southeast tended to decrease, then shrank from northwest, northeast and southwest to southeast, with the increasing fluctuations in southeast. The study has certain reference significance for flood control and disaster reduction and water resources planning and utilization. [ABSTRACT FROM AUTHOR]

Based on data of hail days at 2 481 stations during 1961 -2016, the temporal and spatial distribution characteristics and periodic variation of gale days in China and seven geographical regions were analyzed by using a variety of statistical methods. The results showed that: in time, the gale days in China and the seven geographical areas all showed a decreasing trend from 1961 to 2016. In the Tibet (Southeast China and Southwest China) region, the annual number of single-station gale days was the most (least), but the decrease ratio was the least (most). In the significance oscillation period, it was 14 years in the whole country, 60 years in Northeastern China, Northern China and east part of Northwestern China, 7, 14 and 60 years in the west of Northwestern China, Southwestern China and Southeastern China, 7 and 60 years in the Tibet region. The mutation of gale days generally occurred in 1991, 1993, 1989, 1997, 1986, 1997, 1992 and 1984 in the whole country. Northeastern China, Northern China, east part of Northwestern China, west part of Northwestern China, Tibet, Southwestern China and Southeastern China, but only the east of Northwestern China and Tibet region passed 0.05 of significance test. In space, the annual average gale days showed the pattern of southeast low and northwest high in China from 1961 to 2016. The annual average gale days were more abundant in the central and western Tibet, the southern Qinghai, eastern Xinjiang, western Sichuan, northern Inner Mongolia and northern Gansu. These regions were dominated by positive anomaly in the 1970s and the 1980s, but negative in other decades. Annual gale days in most regions of China showed a decreasing trend during 1961-2016, and fluctuation presented high in east region and low in west region beside " Hu Huanyong line". [ABSTRACT FROM AUTHOR]