与冬季北太平洋大范围海温异常相联系的海气特征
投稿时间: 2016-11-07  最后修改时间: 2017-01-16  点此下载全文
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作者单位E-mail
徐海明 南京信息工程大学 hxu@nuist.edu.cn 
崔梦雪 南京信息工程大学  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:本文采用1948年至2014年NCEP/NCAR大气再分析资料以及延伸重建海温资料,基于大气海洋间不同的主导关系对冬季北太平洋大范围海温异常进行分类,探究相应的海气结构特征。统计结果表明,大气影响海洋个例多于海洋影响大气的个例,即在冬季北太平洋大气强迫海洋占主要地位,但也存在海洋对大气的反馈作用。对于大气影响海洋而言,SST暖异常区上空主要伴随着东北—西南走向的相当正压高低压异常(东北高西南低),对应于东南风异常以及显著的深厚暖异常,表现出相当正压暖/脊结构,冷异常情况与此相反;SST异常为净热通量异常与风速异常共同作用引起。而对于海洋影响大气而言,在SST暖异常区上空西部为南北向高低压异常(北高南低),东部为低压异常,对应于偏东风异常,在SST冷异常区上空为偶极型的南北向高低压异常(南高北低),对应于偏西风异常;位势高度异常表现出相当正压结构且较大气影响海洋时相应偏弱,大气暖(冷)温度异常比较浅薄且主要局限于对流层低层。海洋温度结构异常主要表现为,在大气影响海洋时海温异常由表层下传,海洋影响大气时为上下一致的温度异常。
中文关键词:大范围海温异常 中纬度北太平洋 大气海洋特征 冬季
 
Atmospheric-oceanic features associated with large scale SST anomalies over the North Pacific in winter
Abstract:This atmosphere and oceanic features in association with large scale sea surface temperature (SST) anomalies over the North Pacific in winter are examined in terms of their dominant roles in local air-sea interactions by using NCEP/NCAR Reanalysis and Extended Reconstructed Sea Surface Temperature during the period of 1948-2014. Statistic results indicate that more cases of atmospheric forcing to the ocean are identified, indicating that atmospheric forcing to the underlying ocean plays a dominant role in local air-sea interaction over the North Pacific in winter. However there still exist some cases for oceanic forcing to the overlying atmosphere, indicative of oceanic feedback. As the cases for atmospheric forcing to the ocean, a dipole pattern of geopotential height anomalies (an anomaly anticyclone in the northeast, while an anomaly cyclone in the southeast), together with southeasterly and deep warm anomalies just lie over the positive SST anomalies, indicative of equivalent barotropic atmospheric structures, and vice versa for these large scale SST anomalies. As the cases for oceanic forcing to the atmosphere, a triple pattern of geopotential height anomalies (an anomaly anticyclone in the northwest, an anomaly cyclone in the southwest, and an anomaly cyclone in the east) along with surface easterly anomalies are located over the positive SST anomalies, however a pair of geopotential height anomalies (an anomaly anticyclone in the south, and an anomaly cyclone in the east) along with surface westerly wind anomalies appear over the negative SST anomalies. Over all, geopotential height anomalies still have the same equivalent barotropic structure features as the cases of atmospheric forcing to the ocean, however their values are much small and mainly limited to the lower troposphere. In additions, ocean temperature anomalies propagate downward when the atmospheric forcing dominates, while ocean temperature anomalies are almost stationary when the oceanic forcing plays an active role.
keywords:Large scale SST anomalies, North Pacific, Atmosphere and ocean features, winter
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