北半球夏季海洋性大陆区域气候与EP型ENSO:直接与间接联系

发布时间：2018-03-29 21:09

本文选题：海洋性大陆　切入点：降水异常　出处：《大气科学学报》2016年03期

【摘要】：利用1979—2009年的NECP资料、Hadley海温月平均资料和CMAP降水资料,采用Kao and Yu(2009)的方法定义了夏季EP型ENSO指数EPI,用合成分析的方法分析了东部型ENSO与海洋性大陆降水的关系。结果表明:EPI与MC(Maritime Continent,海洋性大陆)区域降水变化间存在非常弱的负相关。造成这一弱相关的原因是EPI与MC区域降水在某些年份存在同号变化。在剔除Ni錺o4信号后,海洋性大陆区域降水序列与EPI与存在着同号和反号两种关系。反号关系是通常所认为的,当经典的El Ni錺o(La Ni錺a)发生时MC区域降水出现显著地减少(增多)。此时,沿赤道的异常Walker环流建立了EP型ENSO与MC区域气候间的直接联系。而在同号关系时,菲律宾以东异常加热和SPCZ区域异常冷却引起的西北—东南走向的垂直环流圈削弱了MC区域与赤道东太平洋之间的异常Walker环流所建立的直接联系,或者说,赤道东太平洋区域SSTA与MC区域降水异常的形成是通过SPCZ区域SST的反号异常而产生间接联系的。这种机制的揭示为深刻认识ENSO影响海洋性大陆区域甚至东亚地区气候变动的联系提供了新的线索。
[Abstract]:Using the NECP data from 1979 to 2009, the monthly mean data of Hadley SST and the CMAP precipitation data are used. The EP-type ENSO index in summer is defined by the method of Kao and. The relationship between the eastern type ENSO and the oceanic continental precipitation is analyzed by the method of composite analysis. The results show that there is a non-existence between the regional precipitation variation of the ENSO and MC(Maritime Continent (oceanic continent). The reason for this weak correlation is that the precipitation in EPI and MC region has the same change in some years. There are two kinds of relations between the precipitation sequence of oceanic continental region and EPI. The inverse relationship is generally considered, and the precipitation in MC region decreases significantly when the classical El Ni o(La Ni La) occurs. The anomalous Walker circulation along the equator establishes a direct connection between EP type ENSO and MC regional climate. The anomalous heating to the east of the Philippines and anomalous cooling in the SPCZ region result in a vertical circulation circle in the north-southeast strike which weakens the direct connection between the MC region and the anomalous Walker circulation in the equatorial eastern Pacific Ocean, or, in other words, the anomalous Walker circulation in the equatorial eastern Pacific. The formation of SSTA and MC precipitation anomalies in the equatorial eastern Pacific region is indirectly associated with the reverse sign anomaly of SST in the SPCZ region. This mechanism is revealed as a profound understanding of the influence of ENSO on the atmosphere in the oceanic continental region and even in the East Asian region. The ever-changing link provides new clues.
【作者单位】：南京信息工程大学气象灾害教育部重点实验室;南京信息工程大学气象灾害预报预警与评估协同创新中心;杭州市气象局;
【基金】：国家自然科学基金资助项目(41330425) 公益性行业(气象)科研专项(GYHY20140624)
【分类号】：P732;P461.2

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