| Meso-small scale strong convection weather events usually contain a great destructive power.At present,a large number of researches mainly focus on its prediction and occurrence mechanism,but seldom analyze its inter-annual scale changes from the perspective of climate.In this paper,a newly developed China meso-small scale strong convection weather events dataset,including 2332 national observation stations,has updated to 2015(1961-2015),are used to analyze the climatologic characteristics of strong convection weather events(thunderstorm,lightning,hail and strong wind)on the year,the season,and the month scales over mainland China,at the same time briefly analyze the relationship between them and their long-term trends.The results have a practical significance for prediction,prediction and impact assessment to meso-small scale strong convection weather.The main conclusions are as follows:1.From 1961 to 2015,the occurrence frequency of thunderstorm,lightning,hail and strong wind are 39.23 d/yr,20.56 d/yr,1.07 d/yr and 12.50 d/yr,respectively.Thunderstorm and lightning mainly occurred in summer season,while most of the thunderstorm occurred in July and most of lightning occurred in August.Hail mainly occurred between May and September,and the highest frequency occurred in June.Strong wind has a strong area characteristics,concentrated occurrence time in each area is not consistent.In space,the high frequency areas of thunderstorms are similar to those of lightning,where mainly include south and southwest China,and the Qinghai-Tibet Plateau.The occurrence frequency of hail is closely related to the topography,therefore,the high frequency areas of hail are mainly distribute in the Qinghai-Tibet Plateau,the eastern part of the Inner Mongolia Plateau and the mountainous areas of the central and western China,while the southeast coastal areas have lower frequency than other areas.And the characteristics of strong wind are obviously different to the first three meso-small scale strong convection weather events.It has the spatial distribution characteristics like more in the western part and less in the eastern part.2.From 1961 to 2015,the incidence of thunderstorms,lightning,hail and strong wind inthe whole country in the last 50 years show a significant downward trend,with a decrease of2.71d/10 yr,6.50d/10 yr,0.32d/10 yr and 3.62d/10 yr.The decrease of lightning is the most obvious in four meso-small scale strong convection weather events.In the seasonal study,thunderstorms,lightning and hail are the most obvious decrease in summer,but the strong wind is the most obvious trend in spring.Four kinds of meso-small scale strong convection weather events have been decreasing more obviously since the 1990 s.In space,meso-small scale strong convection weather events show a nation wide range of consistency decline.Four strong meso-small scale strong convection weather events are on the decline of 2.5 ° x2.5 ° grid account for more than 95% of all the grid number.In the high value region of climatology distribution,the trend is more significant.3.In addition,the relationship between four strong meso-small scale strong convection weather events and the relationship between them and elevation are found.There is a good correlation of the annual average occurrence frequency between thunderstorm and lightning,and the coefficient can reach 0.65.Thunderstorm,hail and strong wind increase significantly with elevation,especially for hail and strong wind,with an increase of 2.87d/500 m,1.80d/500 m and 8.16d/500 m respectively.But lightning does not correspond to elevation.It shows that the elevation has important influence on the formation and development of thunderstorm,hail and strong wind of strong convective weather. |
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