摘要
分别对5月和6～8月东亚东北冷涡活动典型的多寡年份北半球500hPa高度距平场进行合成、频次累积和相关分析，结果表明：东亚东北冷涡持续性活动不仅与前期、同期和后期北半球的大气环流异常密切相关，而且也是异常区的重要组成部分;500hPa 5月和6～8月东北冷涡治动多寡年的同期500hPa高度距平合成场差异显著;6～8月东北冷涡典型多寡年的同期距平场均与前冬（12～2月）的主要异常区反位相,存在半年尺度的遥相关，与北太平洋涛动（NPO）类同的500 hPa高度距平场，如前冬呈正位相,预报6～8月东北冷涡持续活动弱,反之，冷涡持续活动强；合成场和相关场通过信度检验的关键区主要位于东亚中高纬度至阿留申群岛及其以南的副热带地区、青藏高原接近巴基斯坦一侧和北非乍得盆地与撒哈拉大沙漠等地区；由此可以认为东亚地区中高纬度5月和6～8月东北冷涡持续性活动是北半球大气环流异常待续或调整的重要表征。
Abstract The composition, frequency cumulation and correlation analysis of 500 hPa anomaly field arc respectively studied over the Northern Hemisphere in more and fewer years of the cold vortex activities on the northeastern of East Asia (NCVAEA) in May and summer (JJA). The results indicate that persistent activities are not only closely related lo anomalous general circulation over the Northern Hemisphere in the preceding, current and later periods, hut also are an important part of the anomalous area. The fields in the same period with action of NCVAEA have marked different. The departure field at the same lime (JJA) has an opposite phase in comparison with the main abnormal areas in the last winter (DJF); in other words, there is a tcleconncction on half-year scale between (hem. The 500 hPa departure field is similar to North Pacific Oscillation (NPO). If the field has a positivc-of-phase compared with the last winter (DJF), the weak persistence would be predicted. Conversely, the strong JJA cold vortex would be predicted. The key regions tested are located from middle-high latitudes over East Asia lo the Aleutian Islands and corresponding subtropical areas, the Qinghai-Xizang Plateau close to Pakistan, the Chad Basin of North Africa and the Sahara etc. It follows from this that the NCVAHA persistent activities over middle-high latitudes of East Asia are important characteristics of'lhe Northern Hemisphere general circulation in May and summer (JJA).
出处
《大气科学》
CSCD
北大核心
2002年第3期361-372,共12页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目49875022
