近40年来西北低涡的统计  

Statistics of Northwest Vortex in Recent 40 Years

作　　者：梁宁 刘海文 潘丽丽[2] LIANG Ning;LIU Hai-wen(Chengdu University of Information Technology,Chengdu 610225,China;Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]成都信息工程大学,四川成都610225 [2]中国民航大学空中交通管理学院,天津300300

出　　处：《成都信息工程大学学报》2018年第6期675-680,共6页Journal of Chengdu University of Information Technology

基　　金：国家自然科学基金重点资助项目(91337215;41475051);四川省科技计划项目应用基础计划资助项目(2015JY0109)

摘　　要：为了研究西北低涡的长期变化特征,利用CFSR 1日4次再分析资料,采用常规的统计方法,对1979-2016年夏季(6-8月)西北低涡的中心位置、移动情况、维持时间长短等方面进行统计,主要结果有:(1)从气候学上讲,夏季西北低涡中心位置主要位于两个区域,一个位于37.5°N～38.5°N,97.5°E～99°E,占总数的22.4%;另一个则位于35°N,97.5°E～100.5°E,占总数的15.5%。(2)近38年来,夏季共出现1306例西北低涡,平均每年34.4个,低涡次数呈减少趋势。(3)在夏季3个月中,6月西北低涡的出现次数最多,7月次之,8月最少,而且西北低涡白天出现的概率大于夜间。(4)在所有西北低涡中,有41.2%的低涡属于移出型。(5)西北低涡的维持时间较短,2/3以上的西北低涡维持在1 d以内,维持时间超过2 d的低涡多在7月出现,且91%属于移出型低涡。(6)38年来,夏季西北低涡维持时间超过1 d以上的移出型低涡主要向东南方向、正东方向、偏南方向、东北方向移动,其中东南移向的低涡个数最多,东北移向和正东移向中主要由维持时间在1 d以上的西北低涡所构成。In order to study the long-term change characteristics of the northwest vortex,such statistics have been made on the center position,movement,the time of maintenance of the northwest vortex in summer(June to August) from1979 to 2016.The main results are as follows:(1) Climatically speaking,the appearance of northwest vortex mainly centralized in two position,one lay in 37.5 °N-38.5 °N,97.5 °E-99 °E,which accounted for 22.4%,and another lay in 35 °N,97.5 °E-100.5 °E accounting for 15.5%.(2) In the past 38 years,a total of 1306 northwest vortexes have occurred in summer with an average of 34.4 every year,and the number of the vortexes has been decreased.(3) During the three months in summer,the number of vortexes in June was more than that of the other two months,followed by July and the number of those in August was the least.The possibility of the vortexes appearing in the day was also higher than that in the night.(4) 41.2% of the vortexes were removal type among all the northwest vortex.(5) The time of maintenance of northwest vortex was short,about two thirds of those could last one day or less.Those which could last two days or more mainly appeared in July,and 91% of them were removal type.(6) In the past 38 years,those northwest removal-type vortexes in summer,which could last more than one day,mainly moved towards southeast,east,south and northeast.Most of them moved to southeast,and those northwest eddies which could last more than one day mainly moved to northeast and east.

关 键 词：气候学 西北低涡 统计分析 气候特征 移动方向 

分 类 号：P447[天文地球—大气科学及气象学]