The Trend and Distribution of Thunderstorm Activity and Influencing Factors in Nagqu Prefecture
-
摘要: 利用1966—2011年西藏自治区那曲地区所辖7个气象站的雷暴天气历史观测资料,综合运用天气学及线性统计方法、小波分析方法,分析那曲地区雷暴日数的时间和空间分布规律及影响因素。结果表明:那曲地区的雷暴日数存在显著减少趋势,减少趋势达到0.01的显著性水平,变化倾向率为每10年减少5 d;那曲地区雷暴日数空间分布特征为北部多南部少,东部高山峡谷多于西部湖盆;雷暴日数高值出现在东北部,低值出现在东南部。季节分布为夏季最多,春、秋季相对较少,冬季很少出现雷暴;雷暴初日推迟,而雷暴终日提前,雷暴期有缩短趋势。多雷期、少雷期的差异主要表现在西太平洋副热带高压脊线西伸脊点的经度位置、巴尔克什湖东部至青藏高原处高压脊和高原短波槽的位置和强弱上。那曲地区5—9月雷暴日数存在5~10年、20年两种尺度的周期变化规律,从不同时间尺度周期的变化趋势可以看出那曲地区将逐渐进入多雷期。Abstract: Using synoptic meteorology, linear statistical methods and wavelet analysis, thunderstorm data from seven meteorological observatories in Nagqu Prefecture from 1966 to 2011 are analyzed to find the trend and space distribution of the number of thunderstorm days and influencing factors. A significant decreasing trend is found in the number of annual thunderstorm days, and the decreasing rate is around five days per decade. The cause for this trend might be that stronger latitudinal atmospheric circulation and weaker longitudinal circulation in the context of global warming reduces the intensity and frequency of cold air, and the mechanical lifting of moist air, which is not conductive to the formation of thunder clouds. Spatially, there is a deceasing number of thunderstorm days from the north to the south, from high mountainous valleys in the east to plains in the west with the highest number of thunderstorm days in the northeast and the lowest in the southeast. This feature is closely associated with differences in topography, thermal conditions, moisture conditions and climate across the prefecture. Due to high temperatures and strong convective activities in summer, there are significantly more thunderstorm days in spring and fall, and there are less thunderstorm days in winter with cold drying weather and relatively stable atmospheric stratification. As the weather becomes drier in winter, thunderstorms start later and end earlier with a decreasing trend in the period of thunderstorm activity within a year. The inter-annual difference in the number of thunderstorm days mainly depends on the westward move of the subtropical high over the West Pacific Ocean, the position and strength of the ridge line between the east Lake Balkhash high and the Tibetan Plateau high, and the shortwave trough off the Tibetan Plateau. When the west Pacific subtropical high weakens or moves eastward, and the warm moist airflow is prevalent in Nagqu, the number of thunderstorm days is higher. When the west Pacific subtropical high strengthens or moves westward, and the northwest airflow is prevalent in Nagqu, the number of thunderstorm days is lower. Two variation periods of 5-10 years and 20 years are found in the number of mean annual thunderstorm days between May and September. These variations indicate that Nagqu Prefecture will experience a period of a higher number of thunderstorm days.
-
Key words:
- Nagqu Prefecture;
- thunderstorms;
- temporal and spatial variations
-
表 1 1966—2011年那曲地区平均雷暴日数
Table 1 The mean number of thunderstorm days for Nagqu Prefecture from 1966 to 2011
位置 中部 北部 东部 南部 西部 那曲县 安多县 索县 比如县 嘉黎县 班戈县 申扎县 年平均雷暴日数/d 78 72 82 45 53 67 65 表 2 那曲地区1966—2011年雷暴初日、终日出现次数统计
Table 2 Statistics on the monthly starting and ending dates of thunderstorm events in Nagqu Prefecture from 1966 to 2011
月份 那曲县 安多县 索县 比如县 嘉黎县 班戈县 申扎县 初日 终日 初日 终日 初日 终日 初日 终日 初日 终日 初日 终日 初日 终日 1 1 2 1 3 3 3 2 13 4 5 2 4 27 25 28 20 31 23 26 5 15 19 5 8 6 21 20 9 8 12 3 8 6 26 22 10 36 33 41 23 33 19 22 11 2 2 1 7 1 1 12 1 1 -
[1] 张鸿发, 郭三刚, 张义军, 等.青藏高原强对流分布特征.高原气象, 2003, 22(6):558-564. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200306005.htm [2] 张翠华, 言穆弘, 董万胜, 等.青藏高原雷暴天气层结特征分析.高原气象, 2005, 24(5):741-747. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200505012.htm [3] 尤为, 臧增亮, 潘晓滨, 等.夏季青藏高原雷暴天气及其天气学特征的统计分析.高原气象, 2012, 31(6):1523-1529. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX201206007.htm [4] 秦宏德.青藏高原那曲地区强对流天气的大气静力能量垂直分布.高原气象, 1983, 2(1):61-65. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX198301005.htm [5] 卓嘎, 徐祥德.青藏高原对流云团东移发展的不稳定特征.应用气象学报, 2002, 13(4):447-456. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20020460&flag=1 [6] 徐祥德, 陈联寿.青藏高原大气科学试验研究进展.应用气象学报, 2006, 17(6):756-772. doi: 10.11898/1001-7313.20060613 [7] 蔡学湛.青藏高原雪盖与东亚季风异常对华南前汛期降水的影响.应用气象学报, 2001, 12(3):358-366. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20010347&flag=1 [8] 章基嘉, 朱抱真, 朱福康, 等.青藏高原气象学进展.北京:科学出版社, 1988. [9] 程向阳, 谢五三, 刘岩, 等.安徽省近五十年雷暴的时空变化特征及影响因素.长江流域资源与环境, 2012, 21(1):117-121. http://www.cnki.com.cn/Article/CJFDTOTAL-AHSZ201001014.htm [10] 刘雪松, 马玉才, 拉巴, 等.那曲地区牧业气候区划.北京:气象出版社, 2003. [11] 陈辉, 施能, 王永波.北半球500hPa高度场趋势变化与突变.热带气象学报, 2000, 16(3):272-281. http://www.cnki.com.cn/Article/CJFDTOTAL-RDQX200003009.htm [12] 任景轩, 朱克云, 张杰, 等.近30年西藏地区雷暴变化特征.气象科技, 2011, 39(3):289-293. http://www.cnki.com.cn/Article/CJFDTOTAL-XZKJ201409023.htm [13] 假拉, 杜军, 边巴扎西, 等.西藏气象灾害区划研究.北京:气象出版社, 2008. [14] 任崇, 温亚丽.夏季风时期湛江市雷暴日数的变化特征及大气环流条件分析.广东气象, 2012, 34(1):32-34. http://www.cnki.com.cn/Article/CJFDTOTAL-GDCX201201010.htm [15] 张美平, 敖淑珍, 刘翔, 等.广州白云国际机场近46年来雷暴气候的统计特征.应用气象学报, 2004, 15(1):66-73. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20040109&flag=1 [16] 王其洋.那曲地区降水分析.西藏科技, 2006(4):52-54. http://www.cnki.com.cn/Article/CJFDTOTAL-XZKJ200604016.htm [17] 杜军, 周顺武.西藏近40年气温变化的气候特征分析.应用气象学报, 2000, 11(2):221-227. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20000232&flag=1