西太平洋副热带高亚季节内振荡的基本模态及其与低频位势波的关系  

Basic mode of subtropical high’s seasonal oscillation and its relationship with low-frequency potential wave

作　　者：余丹丹[1] 张韧[2] 滕军[1] 万应虎[1] 

机构地区：[1]中国人民解放军61741部队 [2]解放军理工大学气象学院

出　　处：《热带海洋学报》2010年第4期32-39,共8页Journal of Tropical Oceanography

基　　金：江苏省气象灾害重点实验室开放课题(KLME0507);热带海洋气象科学基金(200609);国家自然科学基金资助项目(40375019)

摘　　要：基于NCEP/NCAR再分析资料,采用分层(500hPa、850hPa)与整层(4层)的EOF分解方法,提取出两个含有垂直结构的副热带高压(副高)的基本模态。分析表明,整层与分层EOF得到的模态有很好的一致性,这说明副高的确存在中下层一致的空间分布特征和时间变化规律;进一步引入小波能量谱讨论其周期特征,发现存在明显的20—30d和30—60d低频振荡现象;结合1995年的天气实况,诊断揭示出不同纬度上的低频位势波影响和制约副高活动的可能机理:副热带地区低频位势波影响和制约着副高主体20d左右的中期变动,而副高西端5—10d的短期过程则与热带和高纬地区低频位势波扰动能量在西太平洋地区聚集有关。Based on the daily-averaged data derived from the NCEP/NCAR reanalysis dataset and using the single-layer（500hPa,and 850hPa） and the whole-layer（four layers） EOF methods,the leading modes of the subtropical high with vertical structure are extracted.It is found that the modes obtained by different ways are the same,which implies that there truly exist the same spatial distribution and temporal-change features from high to low of the subtropical high.Further,by applying the wavelet energy spectrum,it is found that there exist marked low-frequency oscillations of 20？30 days and 30？60 days.Considering the weather in 1995,the possible mechanism that the low-frequency potential wave at different latitude restricted the subtropical high in 1995 is diagnosed,i.e.,the low-frequency potential wave of sub-tropical areas restricted the medium-term movement with a period of 20 days of the main body of the subtropical high,while the short-term process with a period of 5？10 days of the western subtropical high was related to the accumulated disturbance energy of the low-frequency potential wave coming from high latitude and tropical areas in the western Pacific region.

关 键 词：天气学 复经验正交函数分析方法 副热带高压 低频位势波 

分 类 号：P732[天文地球—海洋科学] P434.5