宁夏多、少沙尘暴年4月份北半球极涡和高空急流分布特征比较分析  

Comparative analysis on distribution type of polar vortex in northern hemisphere and upper jet in April between more and less sandstorm years in Ningxia

作　　者：彭维耿[1,2] 赵光平[1,3] 陈楠 

机构地区：[1]中国气象局兰州干旱气象研究所,兰州730200 [2]民航宁夏空管分局,银川750007 [3]宁夏气象台,银川750002

出　　处：《干旱区资源与环境》2009年第4期107-114,共8页Journal of Arid Land Resources and Environment

基　　金：国家自然科学基金项目(40575048);江苏省气象灾害重点实验室基金共同资助

摘　　要：利用NCAR/NCEP在分析资料和宁夏中北部沙尘暴观测资料以及中国气象局下发的月平均极涡指数,采用求相关系数和比较分析方法探讨北半球极涡和高空急流与宁夏中北部沙尘暴天气发生频次的关系,研究宁夏沙尘暴天气多年、少年高空急流和极涡的形态及分布特征,结果表明:春季4月份宁夏中北部沙尘暴天气发生频次与高空200hPa副热带急流强度成显著的正相关关系而与中纬度高空200hPa西风急流强度无明显相关;比较多发年和少发年高空急流的配置,总体上,多发年和少发年高空西风急流位置有明显的差异,多发年高空西风急流中心位置偏南,少发年偏北;4月份宁夏中北部沙尘暴天气发生频数与同期亚洲区极涡面积指数、北半球极涡面积指数、北半球极涡强度指数、北半球极涡中心强度均为弱的正相关关系。比较多发年和少发年4月极涡特征,多发年总体极涡偏强,中心位置偏亚洲区;少发年极涡偏弱,极涡收缩。值得一提的是,4月极涡极强时,宁夏中北部沙尘暴反而偏少。By using NCEP/NCAR reanalysis data, conventional observation data of sandstorm in middle and north Ningxia and month - average - polar vortex indexes of China Meteorological Bureau, the relationship between polar vortex in northern hemisphere and upper jet and the frequency of Spring sandstorm in middle and north Ningxia was discussed, and the feature of upper jet and polar vortex between more and less sandstorm years in Ningxia was studied. The results showed that there was significantly positive correlation between the frequency of spring sandstorm in April in middle and north Ningxia and 200hPa subtropical jet strength, yet the frequency of spring sandstorm in April in middle and north Ningxia was not correlated with 200hpa westerly upper - level jet of the middle latitude strength. It was different for the locations of upper westerly jet that central position moved southward in more sandstorm years and northward in less sandstorm years. The frequency of sandstorm in April in middle and north Ningxia had weak positive correlation with Asia polar vortex area index and polar vortex intensity index in northern hemisphere and polar vortex centric intensity. The characteristics of April polar vortex between more and less sandstorm years in Ningxia were compared with each other. The results showed that the intensity of polar vortex were stronger and the central position of polar vortex moved northward in more sandstorm years and weaker and contraction in less sandstorm years.

关 键 词：沙尘暴 高空急流 极涡 

分 类 号：P445.4[天文地球—大气科学及气象学]