摘要:基于NASA遥感系统提供的2003~2015年全球高分辨率海表温度资料，应用经验正交函数分析、时滞相关分析等方法，对北太平洋冬季黑潮延伸体区海温异常特征及其与热带海表温度的可能关系进行了初步分析。研究发现，冬季延伸体区的海温异常主要表现为两类结构特征，其一为上游区域发展型，包括海盆尺度一致性变化的季节模态和纬向反位相的收缩型结构；其二为纬向延展型，包括分叉东扩结构和通道东扩结构，且该两结构型在2010年前反位相，使得2006年前暖异常东扩路径基本控制在36°N以南，其后至2010年期间，暖异常东扩路径偏北，而2010年后结构型转为同位相，暖异常东扩路径偏北。分叉东扩结构表现为与热带海温变化紧密相关，进一步的时滞相关分析与合成分析表明，热带太平洋不同地区对中纬度海温分叉东扩的影响存在差异，Ni?o3区海温异常超前延伸体区分叉东扩模态约1~2个月，而Ni?o3.4区及Ni?o4区则与延伸体区海温分叉东扩保持前后各约3个月的宽谱同期负相关，或可表明El Ni?o的东部型和中部型对中纬度延伸体暖流分叉东扩存在超前和同期相关影响，且中部型影响更显著。
关键词:黑潮延伸体/
El Ni?o/
经验正交函数分析(EOF)/
相关分析/
海温异常
Abstract:Based on the high-resolution SST dataset from 2003 to 2015 provided by the remote sensing system of NASA, the possible relationship between wintertime SST anomaly (SSTA) characteristics over the Kuroshio Extension in the North Pacific and tropical SST is investigated in this study. The methods used include empirical orthogonal function analysis and time-lagged correlation analysis, etc. The results show that the wintertime SSTA over the Kuroshio Extension presents two types of structural characteristics, i.e., the type of upstream area development and the type of zonal extension. The latter involves two zonal expansion modes with the bifurcation structure and the channeling structure, respectively. The two expansion modes are in opposite phase and in the same phase before and after 2010, respectively. The eastward extension of the warm anomalies was limited to the south of 36°N before 2006, whereas the extension shifted to the northern path during 2006 to 2010 and after 2010. The bifurcation extending mode are closely related to tropical SST variation. Further studies by time-lag correlation analysis and composite analysis indicate diverse impacts on the bifurcation mode of SST over different regions in the tropical Pacific. Ni?o3 SST index led the bifurcation mode over the Kuroshio Extension SSTA by 1-2 months, while Ni?o3.4 and Ni?o4 indexes are correlated with the bifurcation mode at a lead and lag of 3-month respectively, which indicates that the eastern type and central type of El Ni?o may have the lead and concurrent correlation relationships with the bifurcation mode, respectively, and the latter is more remarkable.
Key words:Kuroshio extension/
El Ni?o/
Empirical orthogonal function (EOF)/
Correlation analysis/
SST anomaly
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