风应力引起中东太平洋赤道潜流变异的动力通道  

DYNAMIC CHANNEL FOR THE EQUATORIAL UNDERCURRENT VARIATION IN THE CENTRAL AND EASTERN EQUATORIAL PACIFIC INDUCED BY WIND STRESS

作　　者：王锦 刘传玉[2,3] 杨伟生 WANG Jin;LIU Chuan-Yu;YANG Wei-Sheng(Department of Mathematics and Physics,Luoyang Institute of Science and Technology,Luoyang 471023,China;Key Laboratory of Ocean Circulation and Waves,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Laoshan Laboratory,Qingdao 266237,China)

机构地区：[1]洛阳理工学院数学与物理教学部,河南洛阳471023 [2]中国科学院海洋环流与波动重点实验室,山东青岛266071 [3]崂山实验室,山东青岛266237

出　　处：《海洋与湖沼》2024年第6期1337-1349,共13页Oceanologia Et Limnologia Sinica

基　　金：崂山实验室科技创新项目,2022LSL010302号;国家自然科学基金项目,42090044号。

摘　　要：太平洋赤道潜流(equatorial undercurrent, EUC)通过影响暖池和冷舌水体交换,对于赤道环流系统的动力过程及其全球气候效应具有重要意义。然而,影响EUC强度变异的风应力结构、触发位置和时期及物理机制并不清晰。基于GECCO (German Contribution to the Estimation of the Circulation and Climate of the Ocean)系统伴随模式,研究了在超前1 a内能够使得140°W断面处EUC流量发生最大变异的风应力扰动结构,及其驱动下EUC变异的物理机制。结果表明:(1)影响EUC变异的敏感风应力主要分布于热带太平洋(15°S~15°N之间),呈现出关于赤道对称的“漏斗”状结构,并随着临近目标月份,呈现自西向东的移动趋势,且EUC流量对纬向风应力的敏感性更强,最大的敏感性强度发生在超前1~3个月内。(2)敏感风应力扰动能够有效引发目标月份EUC流量变异,其中,超前4~11个月的非局地风扰动会导致海盆尺度的EUC增强,超前小于4个月的局地风扰动仅能够导致目标断面附近(±10°)的EUC增强。(3)通过分析海表面高度异常的发展过程,敏感风扰动所激发的赤道Kelvin波、赤道Rossby波及其反射波相互叠加是导致EUC变异的主要原因。上述结果确立了风应力通过赤道波动过程激发中东太平洋局地EUC变异的动力通道。The Pacific equatorial undercurrent(EUC)has important implications for the dynamics of the equatorial circulation system and its global climate effects by affecting the exchange of water between the warm pool and the cold tongue.However,the spatial pattern,triggered locations,and timings of the effective wind stress affecting EUC variation and its underlying physical mechanisms are not clear.Based on the German Contribution to the Estimation of the Circulation and Climate of the Ocean(GECCO)system adjoint model,the wind stress perturbation structure that can cause the maximum variation of EUC at the 140°W section within one year ahead and the physical mechanism of EUC variation driven by it were studied.Results indicate that the adjoint-sensitivity wind stresses affecting EUC variation is distributed in the tropical Pacific between 15°S~15°N,exhibiting a funnel-shaped structure that is symmetrical about the equator,and as the target month approaches,it shows a trend of moving from west to east,and the EUC is more sensitive to zonal wind stress,with the maximum sensitivity occurring within 1-3 months in advance.The adjoint-sensitivity wind stress perturbation can effectively trigger EUC variation in the target month.Among them,non-local wind perturbation with a lead-time of 4 to 11 months can enhance EUC at the basin scale,while local wind perturbation with a lead-time of less than 4 months can only lead to EUC enhancement near the target section(±10°).By analyzing the development of sea surface height anomalies,the superposition of equatorial Kelvin waves,equatorial Rossby waves,and their reflected waves excited by adjoint-sensitivity wind perturbation is the main reason of EUC variation.The above results establish the dynamic channel for wind stress to excite local EUC variation in the central and eastern equatorial Pacific through the equatorial wave process.

关 键 词：太平洋赤道潜流 伴随敏感性 风速扰动 ROSSBY波 KELVIN波 

分 类 号：P731.21[天文地球—海洋科学]