金晨阳,张文君. 2020. 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, (0):-, doi:10.11676/qxxb2020.014
赤道太平洋高低频纬向环流差异及其物理机制
Different features between high- and low- frequency equatorial Pacific zonal circulations and their possible mechanisms
投稿时间:2019-06-06  修订日期:2019-09-10
DOI:10.11676/qxxb2020.014
中文关键词:  赤道太平洋,纬向环流,海气耦合,时间尺度
英文关键词:Equatorial Pacific,Zonal atmospheric circulation,Ocean-atmosphere coupling,Timescale
基金项目:国家自然科学基金,国家重点基础研究发展计划,全球变化与海气相互作用专项
作者单位E-mail
金晨阳 南京信息工程大学 jcymurphy@163.com 
张文君 南京信息工程大学 zhangwj@nuist.edu.cn 
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中文摘要:
      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,而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,传播速度大概为5m?s-1,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尺度依赖性,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Kelvin波横穿太平洋时间相当。
英文摘要:
      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 European Medium-Range Weather Forecast Center reanalysis data and National Oceanic and Atmospheric Administration observational data from 1982 to 2017. Especially, the differences of the 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 Southern Oscillation only exists on the low-frequency timescale but absent on the high-frequency timescale. On the low-frequency timescale, it is mainly modulated by the ENSO signal 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 basin consistent pattern in the whole equatorial Pacific. The high-frequency zonal atmospheric feature is very like that of Madden-Julien Oscillation (MJO), both owning the eastward propagation speed about 5m?s-1 and 34% of its variance can be explained by MJO linearly. 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 time for that the equatorial oceanic kelvin wave traverses the equatorial Pacific.
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