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利用NCEP风场、HadISST海温及PREC降水数据,将1950年以来的14次LaNia事件分为东部型和中部型两类,并进一步研究了两类LaNia事件的海温发展演变特征以及热带大气响应特征的差异.LaNia事件的分类基于的是成熟期标准化的Nio3和Nio4指数及成熟期海温距平的空间分布特征.在东部型LaNia事件的成熟期,海温负距平绝对值的最大值主要分布在赤道东太平洋,而中部型LaNia事件达到成熟时海温负距平中心向西移动到赤道中太平洋日界线附近.中部型LaNia的强度比东部型强,并且赤道太平洋东西海温差异也较大.受中部型LaNia海温分布特征的影响,赤道东太平洋异常的下沉运动西移到日界线附近,低层异常辐散高层异常辐合的中心也相应西移,热带风场对两种分布类型LaNia的响应差异在对流层高层200hPa表现的更加显著.但是,两类LaNia成熟期热带降水异常的分布特征差异很小,只是中部型LaNia事件导致的赤道太平洋中部降水偏少和赤道东印度洋至西太平洋降水偏多的特征更明显.
Based on the NCEP wind field, HadISST sea surface temperature and PREC precipitation data, the 14 LaNia events since 1950 are divided into two types: east type and middle type, and the characteristics of SST in two types of LaNia events are further studied And the differences in the response characteristics of the tropical atmosphere.The classification of LaNia events is based on the normalized Nio3 and Nio4 indices of maturity and the spatial distribution of SST anomalies at maturity.When maturing the eastern LaNia event, SST The maximum value of negative anomaly is mainly distributed in the equatorial eastern Pacific, while the central LaNia event reaches maturity, and the negative anomalous center of SST moves westward to near the mid-equatorial Pacific coastline.The intensity ratio of middle LaNia The eastern part is strong and the difference between the eastern and western sea temperatures is also large in the equatorial Pacific.According to the distribution characteristics of the central LaNia sea temperature, the anomalous sinking movement in the eastern equatorial Pacific moves westward near the daily boundary, The center of the co-occurrence also moved westward, and the difference in response of the tropical wind to the two distribution types, LaNia, was more pronounced at 200hPa in the upper troposphere. However, the distribution of tropical precipitation anomalies in the two mature stages of LaNia The difference is small, but the Central Plains LaNia event caused less precipitation in the central equatorial Pacific and more precipitation in the equatorial East Indian Ocean to the western Pacific.