摘要
在北半球的春季,热带三大洋的海洋–大气系统年际变化会对同期太平洋厄尔尼诺–南方涛动(El Niño-Southern oscillation,ENSO)产生响应,同时也能通过区域海洋–大气耦合过程影响ENSO的发展。基于国际公开使用的海表温度资料和降水资料,通过联合正交经验分解方法分析,可以发现全球大洋春季存在两种显著的海气耦合模态。第一模态表现为:在热带中东太平洋,海表温度增暖、降水增多;在热带大西洋和热带印度洋,降水呈现经向偶极型分布以及跨赤道的海表温度梯度异常;即伴随ENSO在春季消亡期的空间型态,大西洋出现经向模态,印度洋出现反对称模态。第二模态表现为:太平洋经向海表温度和降水模态,即太平洋经向模态。回归分析结果表明,ENSO盛期的大气环流调整引起了热带大西洋和印度洋降水辐合带异常,并通过海面风场异常激发海盆内部的海洋–大气反馈,引起春季经向模态。进一步研究发现,冬、春季大西洋和印度洋热带辐合带分别位于赤道以北和以南,导致两个海盆经向模态的降水异常相对赤道呈反对称分布。在春季,太平洋经向模态的暖中心延伸到赤道上,引起西风异常,为后续El Niño的发展提供了有利条件。文章揭示了太平洋ENSO与春季热带三大洋经向模态之间的关系,这有助于更好地理解热带气候模态的季节性“足迹”的发展过程。
The tropical ocean-atmosphere system in spring may simultaneously respond to the El Niño-Southern Oscillation(ENSO)in the Pacific ocean.At the same time,it can affect the ENSO development through coupled regional ocean-atmosphere interactions.Based on the joint empirical orthogonal function and open-source datasets,we identify two major global climate modes.The first EOF mode presents the ENSO pattern along with the spring meridional mode in the Atlantic and asymmetric mode in the Indian Ocean,in which the sea surface temperature warms up and precipitation increases in the tropical central and eastern Pacific ocean,accompanied by the equator-asymmetric pattern of precipitation in the tropical Atlantic and Indian Oceans as well as anomalous sea surface temperature gradient in the trans-equatorial.Further analyses suggest that the ENSO influences the intertropical convergence zone by adjusting atmospheric circulation during its mature phase and then induces regional ocean-atmosphere feedback resulting in the spring meridional modes.The differences in spring asymmetric modes of precipitation in the tropical Atlantic and the Indian Ocean are determined by the different positions of the intertropical convergence zone in winter and spring.The second mode shows a meridional sea surface temperature and precipitation anomalies in the tropical Pacific,i.e.,the Pacific meridional mode.The warm pole of the spring Pacific meridional mode extends over the equator,causing westerly wind anomalies that favor the El Niño development.This study reveals the relationship between the Pacific ENSO and the global spring meridional mode,contributing to a better understanding of the seasonal'footprint'of tropical climate modes.
作者
张玉红
张涟漪
杜岩
ZHANG Yuhong;ZHANG Lianyi;DU Yan(State Key Laboratory of Tropical Oceanography,Guangdong Key Lab of Ocean Remote Sensing,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing 100049,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China)
出处
《热带海洋学报》
CAS
CSCD
北大核心
2023年第2期34-44,共11页
Journal of Tropical Oceanography
基金
国家自然科学基金项目(41976024,41830538,42090042)
南方海洋科学与工程广东省实验室(广州)项目(2019BT02H594)
热带海洋环境国家重点实验室自主研究项目(LTOZZ2101)。
