摘要
由于北极涡与副热带高压是两个影响我国天气气候变化的主要大气环流实体,两者紧密相联,且均对华北夏季降水有明显作用,本文使用NCEP/NCAR再分析资料、国家气候中心提供的74个大气环流因子及中国160站月降水资料,利用合成分析、相关分析及SVD等方法讨论了夏季北极涡与北半球大气环流及副热带高压的相互关系,分析了夏季北极涡及副高对华北降水的共同作用。结果表明:(1)北极涡的变化不仅与高纬高度场密切相关,而且与中、低纬度环流紧密联系,当极涡异常偏大偏强,中、低纬地区位势高度均明显偏低,北半球副高的面积和强度易偏小,北界位置易偏南,其中副高强度的变化最大。(2)各分区极涡因子与副高因子之间基本呈显著的负相关,而与西太平洋和南海副高的北界、脊线位置呈正相关。(3)极涡指数、副高脊线及北界指数与华北降水之间以正相关为主,副高面积、强度指数与华北降水基本呈负相关。当亚洲和欧洲区极涡异常南扩,北非、大西洋、北美副高显著收缩减弱,西太平洋和南海副高明显北抬时,华北降水易增加。
The northern polar vortex and subtropical high （SH） are two important members of the atmospheric circulation which affect the weather and climate changes in China. They interact with each other closely and have great influence on summer precipitation in North China. Using the NCEP reanalysis data, 74 factors of the atmospheric circulation and monthly precipitation data from 160 stations in China provided by National Climate Center （NCC）, the relationships among the northern polar vortex and the atmospheric circulation and SH during summer have been discussed and the joint effect of the polar vortex and SH on the precipitation in North China have been analyzed by means of composite analysis, correlative analysis and the SVD. The results show that the activity of the northern polar vortex is not only subject to geopotential heights in high latitudes, but also closely related to the circulation in middle and low latitudes. When the area and intensity of the polar vortex are anomalously large, the geopotential heights in the middle and low latitudes are much lower, so that the area and intensity of SH are the smaller, and the northern boundary of SH is more southward, especially for the change of the intensity. There is distinctively negative correlation between most indexes of polar vortex and factors of SH in Northern Hemisphere and transitional zones, while the polar vortex indexes are positively related to the northern boundary and ridge line indexes of SH in West Pacific and South China Sea. Most indexes of the polar vortex, north boundary and ridge line of SH are positively related to summer precipitation in North China, while the area and intensity indexes of SH are negatively correlated with it. In particular, the precipitation in North China increases obviously when the polar vortex anomaly in Asia and Europe enlarges, SH in North Africa, Atlantic, and North America shrink and weaken, and SH in West Pacific and South China Sea jumps northward.
出处
《热带气象学报》
CSCD
北大核心
2008年第4期417-422,共6页
Journal of Tropical Meteorology
基金
国家自然科学基金委重点基金(40633015)
中国气象局新技术推广项目(北半球平流层爆发性增温与极涡活动对东亚对流层阻塞的影响)共同资助
关键词
北极涡
副热带高压
华北夏季降水
northern polar vortex
subtropical high
summer precipitation in North China
