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.

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.

Climatic characteristics of high temperature in East China during 1961-2005

Based on the daily maximum temperature data covering the period 1961-2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days（HTDs）and the mean daily maximum temperature（MDMT）during annual and monthly HTDs in East China were studied.The results show that the mean annual HTDs were 15.1 and the MDMT during annual HTDs was 36.3℃in the past 45 years.Both the mean annual HTDs and the MDMT during annual HTDs were negative anomaly in the1980s and positive anomaly in the other periods of time,oscillating with a cycle of about 12-15 years.The mean annual HTDs were more in the southern part,but less in the northern part of East China.The MDMT during annual HTDs was higher in Zhejiang,Anhui and Jiangxi provinces in the central and western parts of East China.The high temperature process（HTP） was more in the southwestern part,but less in northeastern part of East China.Both the HTDs and the numbers of HTP were at most in July,and the MDMT during monthly HTDs was also the highest in July.In the first 5 years of the 21st century,the mean annual HTDs and the MDMT during annual HTDs increased at most of the stations,both the mean monthly HTDs and the MDMT during monthly HTDs were positive anomalies from April to October,the number of each type of HTP generally was at most and the MDMT in each type of HTP was also the highest.

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.

Spatial and Temporal Variation Characteristics of Gale Days in China from 1961 to 2016

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 1970 s and the 1980 s,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".

Analysis on the Climatic Change Characteristics of the Snow Cover Days and Its Influence Factors in Suzhou during Recent 50 Years

[Objective] The research aimed to study climatic variation characteristics of snow cover days and its influence factors in Suzhou of Anhui Province during recent 50 years. [Method] According to annual snow cover days and correlated data in Suzhou during 1961-2010, by using linear trend method, accumulative anomaly and complete correlation coefficient method, etc., the climatic variation characteristics of snow cover days and its influence factors in Suzhou were analyzed. [Result] In recent 50 years, the snow cover period in Suzhou presented shortened trend. Except days of snow cover (≥20 cm), the annual snow cover days at each thickness all showed varying degrees of decrease trend. The annual snow cover days had wavy decline trend, and the decline amplitude was 0.84 d/10 a. From the 1960s to prior period of the 1970s, the annual snow cover days presented increase trend. From middle and later periods of the 1970s to middle period of the 1980s, the snow cover days was less and gradually increased from later period of the 1980s to the early 1990s. From middle period of the 1990s to 2003, it entered into less snow period again. From 2004 to now, it presented oscillation of snowy and less-snow alternating. The main climatic factor which affected annual snow cover days in Suzhou was average temperature. The second one was average surface temperature. [Conclusion] The research provided theoretical basis for analyzing climate variation in Suzhou under the background of global climate warming.

Analysis on Climatic and Synoptic Characteristics of Thunderstorm Gale Weather in Jiangsu

By using observation and sounding data at 68 artificial observatories of Jiangsu Province during 2009- 2013,thunderstorm gale weather and its climatic characteristics in Jiangsu were conducted statistics. The characteristics of some instability indexes and strong convection parameters were analyzed,and environmental parameters of dry and wet thunderstorm gales were contrasted. Results showed that thunderstorm gale in Jiangsu had the characteristics of high occurrence frequency,local feature and stronger intensity. It was mostly accompanied by precipitation,and had obvious seasonal and daily change characteristics. Synoptics analysis showed that temperature-humidity profile characteristics before thunderstorm gale appeared in Jiangsu mainly had four types： bell mouth type,inverted V type,dry unstable type and wet unstable type. Before thunderstorm gale occurred,atmospheric instability was stronger,and some strong convection parameters all had certain instructions. But the forecasts of some thunderstorm gale processes were easy to be missed by only considering CAPE. Environmental condition difference of generating dry and wet thunderstorm gale was that instability of dry thunderstorm gale was stronger than that of wet thunderstorm gale. Before dry thunderstorm gale occurred,environmental temperature at middle-low layer was lower; lapse rate was larger; humidity was small. Before wet thunderstorm gale occurred,environmental temperature was higher; lapse rate was small; humidity was large. At dynamic structure,vertical wind shear at 0- 6 km of dry thunderstorm gale was significantly stronger than that of wet thunderstorm gale.

张家口市雷暴气候变化特征

利用张家口市1960-2013年近54年以来的地面气象观测站雷暴观测资料,采用线性拟合、气候倾向率、M-K突变检验等方法对该市雷暴气候特征进行分析研究。结果表明:张家口市属于中雷区范围,近54年来张家口市雷暴日大约以1.21d/10a的倾向率减少。夏季雷暴日大约以1.29d/10a的倾向率减少,是雷暴日逐年减少主要原因,其中7月雷暴日减少最为明显。54年中张家口市雷暴日存在两个关键的减少突变点,突变点分别发生在1971年与1998年。雷暴在NW方向出现最多,以E、SE方向最少;在SE方向消散最多,以NW、W方向最少。