| 赤道太平洋高低频纬向环流差异及其物理机制 |
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| 引用本文： | 金晨阳,张文君,刘超.赤道太平洋高低频纬向环流差异及其物理机制[J].气象学报,2020,78(2):187-198. |
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| 作者姓名： | 金晨阳 张文君 刘超 |
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| 作者单位： | 南京信息工程大学气象灾害教育部重点实验室∕气候与环境变化国际合作联合实验室∕气象灾害预报预警与评估协同创新中心，南京， 210044 |
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| 基金项目： | 国家重点研发计划“重大自然灾害监测预警与防范”重点专项项目（2018YFC1506002）、国家自然科学基金项目（41675073）、全球变化与海气相互作用专项（GASI-IPOVAI-03） |
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| 摘 要： | 利用1982—2017年欧洲中期天气预报中心再分析资料和美国国家大气海洋管理局的观测资料，分析了赤道太平洋高、低频海平面气压距平场的特征及差异，并通过诊断赤道太平洋海-气耦合的时间尺度，探讨了导致赤道太平洋高、低频纬向环流差异的原因。结果表明，南方涛动海平面气压东西跷跷板耦合现象只是在低频场中才存在，在高频场中并不存在。低频场上，主要受到热带最明显的年际信号(ENSO)的调控，海平面气压场和海表温度场呈现出东西振荡型。相比而言，在高频场上由于时间短，海、气异常还没有发生较好的耦合，气压场和风场呈现出全海域一致型。高频纬向环流与热带季节内振荡（MJO）紧密联系，具有明显的东传特征，传播速度大约为5 m/s，其变率方差的34%可以由MJO线性解释。相干谱分析表明海-气耦合具有时间依赖性，南方涛动通常只在20候以上的时间尺度才能存在，这与赤道海洋开尔文波横穿太平洋时间相当。
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| 关 键 词： | 赤道太平洋 纬向环流 海-气耦合 时间尺度 |
| 收稿时间： | 2019/6/17 0:00:00 |
| 修稿时间： | 2019/11/6 0:00:00 |
Different features between high- and low-frequency equatorial Pacific zonal circulations and their possible mechanisms |
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| JIN Chenyang,ZHANG Wenjun and LIU Chao.Different features between high- and low-frequency equatorial Pacific zonal circulations and their possible mechanisms[J].Acta Meteorologica Sinica,2020,78(2):187-198. |
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| Authors: | JIN Chenyang ZHANG Wenjun and LIU Chao |
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| Institution: | Key Laboratory of Meteorological Disaster of Ministry of Education，Joint International Research Laboratory of Climate and Environment Change，Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，Nanjing University of Information Science & Technology，Nanjing 210044，China |
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| Abstract: | The characteristics of high- (＜20 pentads) and low-frequency (＞60 pentads) sea level pressure (SLP) anomalies and their differences over the equatorial Pacific Ocean are investigated by using the European Center for Medium-Range Weather Forecasts reanalysis data and the National Oceanic and Atmospheric Administration observational data from 1982 to 2017. Specifically, the differences in zonal atmospheric circulation over the equatorial Pacific between high- and low-frequency are emphasized, and possible reasons for their differences are discussed by diagnosing the timescale of the equatorial Pacific ocean-atmosphere coupling. The results show that the Southern Oscillation only exists on the low-frequency timescale but is absent on the high-frequency timescale. On the low-frequency timescale, it is mainly modulated by ENSO signals through strong ocean-atmosphere interactions. In contrast, on the high-frequency timescale, there is no enough time for the ocean-atmosphere coupling. Correspondingly, SLP and wind anomaly fields display a basin-consistent pattern in the whole equatorial Pacific. The high-frequency zonal atmospheric feature is very similar to that of the Madden-Julian Oscillation (MJO), both having the eastward propagation speed of about 5 m/s, and 34% of the variance of high-frequency zonal atmospheric circulation can be linearly explained by MJO. The coherence spectrum analyses indicate that the ocean-atmosphere coupling is dependent on the timescale. The Southern Oscillation usually exists when the timescale is larger than 20 pentads, similar to the timescale for the equatorial oceanic Kelvin waves to traverse the equatorial Pacific. |
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| Keywords: | Equatorial Pacific Zonal atmospheric circulation Ocean-atmosphere coupling Timescale |
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