| 夏季东亚西风急流扰动异常与副热带高压关系研究 |
| |
| 引用本文： | 杨莲梅,张庆云.夏季东亚西风急流扰动异常与副热带高压关系研究[J].应用气象学报,2007,18(4):452-459. |
| |
| 作者姓名： | 杨莲梅 张庆云 |
| |
| 作者单位： | 1.中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室, 北京 100029 |
| |
| 基金项目： | 中国科学院知识创新工程项目;新疆自然科学基金;新疆维吾尔自治区气象局课题 |
| |
| 摘 要： | 利用1979—2003年NCEP/NCAR月平均再分析资料, 探讨夏季 (6—8月) 200 hPa东亚西风急流扰动异常与南亚高压和西太平洋副热带高压的关系。研究指出:夏季200 hPa东亚西风急流扰动动能加强 (减弱), 东亚西风急流位置偏南 (偏北)、强度偏强 (偏弱); 东亚西风急流扰动动能强弱不仅与北半球西风急流强弱和沿急流的定常扰动有关, 而且还与东亚地区高、中、低纬南北向的扰动波列有关, 亚洲地区是北半球中纬度环球带状波列异常最大的区域。夏季200 hPa东亚西风急流扰动动能加强 (减弱), 南亚高压的特征为位置偏东 (偏西)、强度加强 (减弱); 西太平洋副热带高压的特征为位置偏南 (偏北)。东亚环流特别是500 hPa西太平洋副热带高压对东亚西风带扰动异常的响应由高空东亚西风急流南侧的散度场及其对流层中下层热带和副热带地区的垂直速度距平场变化完成。
|
| 关 键 词： | 东亚西风急流 扰动异常 副热带高压 |
| 收稿时间： | 2006-03-03 |
| 修稿时间： | 2006-03-032007-01-09 |
Relationships Between Perturbation Kinetic Energy Anomaly Along East Asian Westerly Jet and Subtropical High in Summer |
| |
| Yang Lianmei,Zhang Qingyun.Relationships Between Perturbation Kinetic Energy Anomaly Along East Asian Westerly Jet and Subtropical High in Summer[J].Quarterly Journal of Applied Meteorology,2007,18(4):452-459. |
| |
| Authors: | Yang Lianmei Zhang Qingyun |
| |
| Affiliation: | 1.State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 1000292.Institute of Desert Meteorology, China Meteorological Administration, Urumqi 8300023.Graduate University, Chinese Academy of Sciences, Beijing 100039 |
| |
| Abstract: | In summer, upper level subtropical westerly jet stream along 40°N over East Asia is one of the most important large-scale circulation systems which influence weather and climate change over east China. At the same time, it is also a wave-guide along Rossby wave activity.Thus, it is necessary to define an objective and quantitive perturbation kinetic energy (Ek) index along East Asian westerly jet (EAWJ), and Ek annual variation and anomalies are investigated.Moreover, the relationships between Ek and EAWJ intensity and EAWJ position are examined, lastly the configuration and connection processes between Ek variability along EAWJ and South Asia high (SAH) and western pacific subtropical high (WPSH) in summer are confirmed by NCEP/NCAR reanalysis dataset from 1979 to 2003.u basic and v basic are defined by wave number k < 3 based on wind u and v in 200 hPa calculated by Fourier expressions, the perturbation kinetic energy of Rossby wave along EAWJ is defined by k≥3 wave activity, and Rossby wave perturbation (u′, v′)=(u, v)-(ub vb), Ek=(u′·u′+v′·v′)/2 which is averaged in the area of latitude with maxima zonal wind shifted±5°and in 100°—140°E, so normal Ek is defined as Rossby wave activity index along EAWJ which also includes meridional displacement variability of EAWJ.EAWJPI (East Asian westerly jet position index) is defined by the difference of zonal wind in 200 hPa between 35°—40°N, 100°—140°E and 40°—45°N, 100°—140°E, and EAWJII (East Asian westerly jet intensity index) is defined by the summation of zonal wind in 200 hPa averaged by 35°—45°N, 100°—140°E.The results show that EAWJ is southward (northward) than the normal and its intensity becomes stronger (weaker) while Ek strengthened (weakened). Not only Ek variations are associated with EAWJ intensity and steady Rossby wave perturbation along westerly jet in summer, but also south—north wave train anomaly in East Asia. Height anomaly in Asia mid-latitude area is most remarkable.When Ek appears stronger (weaker) than normal, center position of circumglobal wave train wave in mid-latitude zone moves to southern (northern). The correlation coefficient is 0.56 between Ek and SAH intensity, 0.66 between Ek and SAH eastward ridge point position, and-0.52 between Ek and WPSH ridge line position during 1979—2003 summer respectively, all are over 99% level.While Ek appears stronger (weaker) than normal, SAH moves to eastward (westward) and stronger (weaker) than the normal.At the same time, WPSH is southward (northward) than the normal.It is found that the response of WPSH to Ek anomaly is going with the change of divergence-convergence over East Asia in 200 hPa and vertical motion in tropic and subtropical zone from surface to upper air. |
| |
| Keywords: | East Asian westerly jet stream perturbation kinetic energy subtropical high |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《应用气象学报》浏览原始摘要信息 |
|
点击此处可从《应用气象学报》下载全文 |
|
