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| 东亚季风指数及其与大尺度热力环流年际变化关系 | |
| 引用本文： | 祝从文,何金海,吴国雄.东亚季风指数及其与大尺度热力环流年际变化关系[J].气象学报,2000,58(4):391-402. |
| 作者姓名： | 祝从文 何金海 吴国雄 |
| 作者单位： | 1. 中国气象科学研究院,北京,100081 2. 南京气象学院气象系,南京,210044 3. 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(LASG),北京,100080 |
| 基金项目： | 国家基金委员会重点项目!4 963 51 70和项目 4 95752 61 |
| 摘 要： | 将东西向海平面气压差与低纬度高、低层纬向风切变相结合 ,定义了东亚季风指数 ,该季风指数较好地反映了东亚冬、夏季风变化。其中 ,夏季风指数年际异常对西太平洋副热带高压南北位置变化和长江中下游旱涝具有较强的反映能力。分析表明 :东亚夏季风年际变化与印度洋 -西太平洋上空反 Walker环流及夏季越赤道南北半球间的季风环流呈显著正相关关系。在强、弱异常东亚夏季风年份 ,异常的 Walker环流在西太平洋上的辐合 (辐散 )中心在垂直方向不重合 ,高层 ( 2 0 0 h Pa)速度势与东亚夏季风显著相关区域位于西北太平洋上 ,该异常环流的高层的辐合 (辐散 )通过改变低层空气质量而影响夏季 50 0 h Pa西北太平洋副热带高压。采用 SVD分析进一步发现 :与海温耦合的异常 Walker环流在西太平洋上空的上升支表现出南北半球关于赤道非对称结构 ,亚澳季风区受该异常 Walker环流控制。因而 ,东亚季风与热带海气相互作用可直接通过这种纬向非对称的 Walker环流发生联系。 |
| 关 键 词： | 季风指数 Walker环流 ENSO 年际变化 |
| 收稿时间： | 1998/11/23 0:00:00 |
| 修稿时间： | 1999/1/25 0:00:00 |
EAST ASIAN MONSOON INDEX AND ITS INTER-ANNUAL RELATIONSHIP WITH LARGESCA-LE THERMAL DYNAMIC CIRCULATION |
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| Zhu Congwen,He Jinhai and Wu Guoxiong.EAST ASIAN MONSOON INDEX AND ITS INTER-ANNUAL RELATIONSHIP WITH LARGESCA-LE THERMAL DYNAMIC CIRCULATION[J].Acta Meteorologica Sinica,2000,58(4):391-402. | |
| Authors: | Zhu Congwen He Jinhai and Wu Guoxiong |
| Abstract: | WT5BZ] A new East Asian monsoon index is developed for land sea between zonal and meridional thermal difference in terms of East Asian zonal sea level pressure contrast combined with high and low level zonal wind shear at low latitudes.The index shown seasonal and interannual variation of summer monsoon goes well with the western Pacific subtropical high (WPSH)ridge and better reflect the drought/flood in the middle low reaches of Yangtze river.Results show that the summer monsoon bears significant anti correlation relationship with the anti Walker circulation over Indian and western Pacific oceans and the cross equatorial monsoon circulation in Asia.The convergence and divergence center of anomalous Walker circulation over western Pacific ocean at low and high level is not vertical superimposed in stronger and weaker summer monsoon year.The pronounced correlation region between velocity potential at 200 hPa level and summer monsoon index is over western North Pacific,thereby the anomalous zonal circulation can affect the WPSH at 500 hPa by virtue of its convergence anomaly.The Walker circulation coupled with SSTA exhibits a meridional asymmetrical character over Australian and Asian monsoon regions on the basis of SVD,there exists directly connection between East Asian monsoon and air sea interaction in the framework of such circulation. |
| Keywords: | Monsoon index Walker circulation ENSO Interannual variability |
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