The assessment of lightning disaster-causing hazards is the key to risk survey of lightning disasters. Following the technical route of the national meteorological disasters comprehensive risk survey since 2020, and based on the lightning location data from 2010 to 2020, lightning disaster data from 2000 to 2020, digital elevation data, and soil conductivity data in Anhui Province, a model diagram of disaster-causing hazard zoning was constructed according to"Specification for meteorological disasters investigation and risk assessment: Lightning". The Analytic Hierarchy Process was used to determine the weight of each index, and the lightning disaster-causing hazard index was then calculated. The zoning of lightning disaster-causing hazards in Anhui Province was completed by combining with GIS technology. The results are as follows. (1) The distributions of lightning strike density and lightning peak current amplitude are closely related to the topography. The altitude and terrain have a positive driving effect on the lightning disaster-causing hazard. (2) The high and relatively high sensitivity of lightning disaster-pregnant areas are mainly located in mountainous regions, along the Yangtze River, and parts of the Huai River basin. (3) The areas of high lightning disasters are mainly located in most regions along the Yangtze River and southern mountainous regions in Anhui Province. The areas of relatively high lightning disasters are mainly located in the southern mountainous region, between the Yangtze River and Huai River, and parts of the Jiangnan region. The areas of low and relatively low lightning disasters are mainly located in the plain and hilly areas in the northern Anhui region and the Jiang-huai region. By comparing the zoning results with historical disaster data, it is found that the distribution of lightning disaster-causing hazard zoning agrees well with the true distribution of disaster, which can provide a reference for future lightning disaster prevention in Anhui Province.

Based on the technical specifications for the national comprehensive risk survey of meteorological disasters, and in view of the characteristics of snow disaster impacts in Anhui Province, the observation element of snow pressure is considered and combined with other disaster causative factors, such as the annual maximum snow depth and annual average snow-covered days to establish a risk assessment model. Using the data of snow depth, snow pressure, and geographic information from 81 national meteorological observation stations in Anhui Province from 1978 to 2020, the spatiotemporal distribution characteristics of various disaster-causing factors are analyzed, and the terrain correction for snow-covered days is performed to obtain a refined assessment of snow disaster risk in Anhui Province. The results are as follows. The annual variation and differences of the average maximum snow depth, average snow-covered days, and maximum snow pressure are significant, but the top three years for all these factors are 2008, 1984, and 2018. The areas with high annual maximum snow depth are mainly concentrated between the Dabie Mountains, the southern Anhui Mountains, and the regions between the Yangtze River and the Huai River. Considering the significant correlation between the annual snow-covered days and elevation in the area above 100 meters and the appropriate sample size, after terrain correction, the high-value areas of snow-covered days are located in the Dabie Mountains and the southern Anhui Mountains, followed by the northwest of Huaibei to the northern foothills of Dabie Mountains. After interpolation calculation of missing measurements, the maximum snow pressure in Xuancheng, Tongling, northern Mount Huangshan, and other places is increased, with distinct localized characteristics. The high-risk areas caused by snow disasters in Anhui Province are mainly located in high-altitude regions such as the Dabie Mountains and the mountainous areas in southern Anhui, while the low-risk areas are mainly located in the eastern part of the Huaibei region, the eastern part of the region between the Yangtze River and Huai River, and the southwestern part along the Yangtze River.

As global warming intensifies, more record-breaking (RB) temperature events are reported in many places around the world where temperatures are higher than ever before. The RB temperatures have caused severe impacts on ecosystems and human society. Here, we address changes in RB temperature events occurring over China in the past (1961–2014) as well as future projections (2006–2100) using observational data and the newly available simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The number of RB events has a significant multi-decadal variability in China, and the intensity expresses a strong decrease from 1961 to 2014. However, more frequent RB events occurred in mid-eastern and northeastern China over last 30 years (1981–2010). Comparisons with observational data indicate multi-model ensemble (MME) simulations from the CMIP5 model perform well in simulating RB events for the historical run period (1961–2005). CMIP5 MME shows a relatively larger uncertainty for the change in intensity. From 2051 to 2100, fewer RB events are projected to occur in most parts of China according to RCP 2.6 scenarios. Over the longer period from 2006 to 2100, a remarkable increase is expected for the entire country according to RCP 8.5 scenarios and the maximum numbers of RB events increase by approximately 600 per year at end of twenty-first century.

By using daily thunderstorm data in 78 stations of Anhui Province during 1961~2009,this paper calculated the sum of annual thunderstorm days in every station and established a time series,then analyzed the spatial-temporal variation of thunderstorm and its influencing factors over Anhui Province by trend analysis,EOF,wavelet analysis,Mann-Kendall test and so on.The results showed that:the annual thunderstorm days over Anhui Province presented a significant decreasing tendency;thunderstorm days in the south overwhelmed that in the north and that in mountain overwhelmed in plain;the seasonal distribution proved that thunderstorm days in summer ranked the first,in spring the second,in autumn the third and in winter the last;the thunderstorm also showed a tendency to begin later and end earlier,thus the thunderstorm period shortened;the thunderstorm days of all stations in Anhui Province decreased,and that of those stations in the southwest of the Yangtze-Huaihe area and the south part of Anhui Province decreased most sharply.The cumulative percent variance of the EOF's first three modes reached 98.7%.The value of first mode of EOF was consistent everywhere,meanwhile the second mode of EOF indicated that the distribution of thunderstorm days between south and north was contrary.Thunderstorm days which mutated once around 1976 had two main periods,around 10~12 years and 2,3 years.The spatial-temporal variation of thunderstorm was closely related to those factors such as atmospheric general circulation,latitude,terrain,season,etc.

Surfaces of temperature at resolution of 1km×1km were generated by Kriging interpolation method, based on the series data from 170 observation stations in Huai River basin from 1961 to 2005. We used the grid data sets to analyze the spatial and temporal variability characteristics of temperature in Huai River basin. Results show that the higher temperature occur in the south and west of the basin, as compared with the lower in the north and east. There is a significantly warming trend in recent 45 years, especially for the northeast of the basin. The changes of temperature of various seasons have different patterns. The mean temperature of spring, autumn, winter and whole year increased significantly in the basin. The winter is characterized by the greatest warming trend, while the summer temperature has a weakly decrease trend. Mann-Kendall trend test indicated that the change of temperature in Huai River basin shifted from cooling to warming trend at 1994.