赤道太平洋上层海洋垂向温度梯度距平与El Nio的关系  

RELATIONSHIPS BETWEEN EL NIO AND VERTICAL DIFFERENCE OF UPPER-LAYER TEMPERATURE ANOMALY IN EQUATORIAL PACIFIC OCEAN

作　　者：蔡怡[1] 宋学家[1] 

机构地区：[1]国家海洋环境预报中心,北京100081

出　　处：《热带海洋学报》2004年第3期36-42,共7页Journal of Tropical Oceanography

基　　金：国家重点自然科学基金资助项目(40231012);国家自然科学基金资助项目(40276002);国家重点基础研究发展规划项目(G1998040900)

摘　　要：用赤道太平洋长达21a的温度资料以及经验正交函数(EOF)分析方法,讨论了在5°S-5°N平均纬向垂直剖面上赤道太平洋垂向温度梯度距平的时空变化,得到了一些有意义的结果。赤道太平洋垂向温度梯度距平EOF分析第1模态的正/负位相反映了El Nino/La Nina发生前赤道太平洋温跃层的分布,第2模态的正/负位相反映了El Nino/La Nina鼎盛以及开始衰减时赤道太平洋温跃层的分布。根据我们对赤道太平洋温跃层核心位置的定义,在El Nino向LaNina转换的过程中,赤道东太平洋温跃层上升了30-40m,而赤道中太平洋温跃层先是上升了40-50m,然后又下降了40-50m,赤道西太平洋温跃层下降了90m;随着赤道西太平洋暖水的堆积以及东移,温跃层首先在赤道西太平洋加深,El Nino发生前赤道中东太平洋温跃层开始加深,El Nino达到鼎盛时赤道西太平洋温跃层抬升,而赤道中东太平洋温跃层加深;赤道太平洋垂向温度梯度距平EOF分析第1特征向量的时间系数与Nino3区的SST距平有非常好的相关,并且超前于Nino3区的SST距平,超前3个月的相关系数高达0.7017,超前6个月的相关系数高达0.6467,因此可以用该量来预测Nino3区的SST距平。Using 21-year temperature data in the Equatorial Pacific Ocean and by EOF a-nalysis, the temporal-spatial change of the vertical difference of upper-layer temperature anomaly in the Equatorial Pacific Ocean is discussed. The results show that the first EOF positive/negative mode of vertical difference of temperature anomaly corresponds to the distribution of thermocline before the occurrence of El Nino/La Nina, and the second positive/negative mode corresponds to the distribution of thermocline during the peak and attenuation periods of El Nino/La Nina. When the pattern changes from El Nino to La Nina, the thermocline rises for 30-40 meters in the eastern Equatorial Pacific Ocean, whereas it firstly rises for 40-50 meters and then falls for 40-50 meters in the central Equatorial Pacific Ocean, and falls for 90 meters in the western Equatorial Pacific Ocean according to our definition to the core position of thermocline in the Equatorial Pacific Ocean. With warm water piling and moving eastward, the thermocline firstly deepens in the western Equatorial Pacific Ocean, and then begins to deepen in the central and eastern Equatorial Pacific Ocean before El Nino. At the peak of El Nino, the thermocline in the western Equatorial Pacific Ocean becomes shallow whereas the thermocline in central and eastern Equatorial Pacific Ocean becomes deep. The time coeffi-cient of the first EOF mode of the vertical difference of temperature anomaly in the E-quatorial Pacific Ocean is ahead of and has a very good correlation with the SST anomaly in Nino 3 region. The correlation coefficient of three months ahead is 0. 701 7, and that of six months ahead is 0. 646 7. So it can be used to forecast SST anomaly in Nino3 region.

关 键 词：垂向温度梯度距平 EOF E1 Nin^~o 

分 类 号：P732.6[天文地球—海洋科学]