Discussion about the Relationship between Thunderstorm Days and Lightning Density

[Objective]The study aimed to discuss the relationship between thunderstorm days and lightning density. [Method]Based on the data of lightning density and thunderstorm days in Dalian region from 2007 to 2011,the optimal radius for the assessment of lightning risk was determined firstly,and then the relationship between thunderstorm days and lightning density in Dalian was fitted using the least square method. [Result]The optimal radius for the assessment of lightning risk was 25 km. The relation between lightning density and thunderstorm days could be fitted well by the formula y =0. 091x2-3. 447 2x ＋34. 713. [Conclusion]The fitting result was consistent with the actual situation,so the formula can be used in relative studies of Dalian.

Climatic Characteristics of the Thunderstorm Days in Heze City in Recent 51 Years

[Objective] The research aimed to study climatic characteristics of the thunderstorm days in Heze in recent 51 years. [Method] Using observation data of the thunderstorm days in Heze from 1961 to 2011, interannual and monthly change characteristics of the thunderstorm days, change trends of the first and final dates, interannual stage distribution were analyzed. [Result] Annual average thunderstorm days in Heze was 25 d. As decade increase, thunderstorm days decreased at 1.9 d/10 a. Thunderstorm days concentrated from April to September, and occurred most often in July. The minimum days from first date to final date was 86 d, and the most days was 264 d. Average first date of the thunderstorm was on April 16, and final date was on September 16. Climatic characteristics of the thunderstorm had significant stage. [Conclusion] The research provided scientific basis for prediction, assessment, prevention and reduction of the thunderstorm disaster in Heze.

Analysis on Climatic Characteristics of Thunderstorms in Doumen District of Zhuhai City during Recent 46 Years

Based on daily data of thunderstorms during 1967 -2012 from the national meteorological station in Doumen District of Zhuhai City, the climatic characteristics of thunderstorms in Doumen District were analyzed using climate tendency rate, sliding t test, trend analysis and experience frequency, The results showed that annual thunderstorm days in Doumen District showed a decreasing trend in recent 46 years; thunderstorms appeared in the whole year; monthly thunderstorm days had two peaks; thunderstorms occurred frequently in summer, especially in August, while thunderstorm days were the least in winter; annual thunderstorm days in Doumen District declined sharply in 1984; most thunderstorms began from middle February to late March and ended from late September to middle November; thunderstorms in Doumen District lasted for a long term, and there was a great change in thunderstorm duration in different years.

Climatic Change Characteristics of Thunderstorm in Zhangjiakou City

In order to understand the climatic change trend and characteristics of thunderstorm in Zhangjiakou City,and provide climate background basis for the thunder prevention and lightning disaster reduction in the region,observation data of the thunderstorm at Zhangjiakou ground meteorological station from 1960 to 2013 were statistically analyzed by linear fitting,climate trend rate,M-K test,guaranteed rate method and so on. The results showed that the average annual thunderstorm days reached 37. 7 d in Zhangjiakou City from 1960 to 2013,and was in the moderate thunderstorm range. In nearly 54 years,thunderstorm day was reducing at the rate of about 1. 21 d /10 a in the city. There was thunderstorm in other three seasons except winter,and thunderstorm frequently occurred in summer. Summer thunderstorm day was reducing at the rate of about 1. 29 d /10 a,which caused the reduction of the annual one. In summer,thunderstorm day of July reduced most significantly. There were two key points of abrupt reduction,which occurred in 1971 and 1998,on the change of thunderstorm days in Zhangjiakou in recent 54 years. The first thunderstorm date had an advancing trend in recent years,while the final date had not an obvious change. The possibility of thunderstorm was very small from late October to next March in Zhangjiakou City. The first thunderstorm date occurred mostly before middle May,and the period from middle and late May to early and middle September was the high incidence of thunderstorm. The thunderstorm occurred mostly in the NW direction,with the least in E and SE directions,and dissipated mostly in SE direction,with the least in NW and W directions.