Roles of Tropical Remote Forcings on the South China Sea Winter Atmospheric and Cold Tongue Variabilities
Roles of Tropical Remote Forcings on the South China Sea Winter Atmospheric and Cold Tongue Variabilities
复制标题
DOI：
10.1175/jcli-d-20-0657.1
复制
发表时间：
2021-02
影响因子：
4.9
通讯作者：
M. X. C. Seow;Y. Morioka;T. Tozuka
中科院分区：
文献类型：
--
作者：
M. X. C. Seow;Y. Morioka;T. Tozuka
利用观测资料、再分析产品和耦合模式试验，研究了热带太平洋和印度洋以及大气内部变率对冬季南海大气环流和冷舌变率的影响，以及年际尺度上遥强迫的相对作用。在观测中，强CT年伴随着当地气旋风异常，这是赤道Rossby波对与拉尼娜现象相关的赤道西太平洋上空比正常情况温暖的对流增强的反应。此外，气旋风异常是一个大气开尔文波的非绝热冷却异常的反应，既衰减晚秋负印度洋偶极子（IOD）和冬季大气内部变率。部分耦合实验表明，热带太平洋海气耦合和大气内部变率对南海CT的耦合变率都有积极贡献，而热带印度洋海气耦合减弱了这种耦合变率。在热带印度洋海气耦合下产生的独立于厄尔尼诺-南方涛动的负IOD之前，西北太平洋反气旋风异常通常会破坏这种变化。
Influences from the tropical Pacific and Indian Oceans and atmospheric internal variability on the South China Sea (SCS) atmospheric circulation and cold tongue (CT) variabilities in boreal winter and the relative roles of remote forcings at interannual time scales are studied using observational data, reanalysis products, and coupled model experiments. In the observation, strong CT years are accompanied by local cyclonic wind anomalies, which are an equatorial Rossby wave response to enhanced convection over the warmer-than-normal western equatorial Pacific associated with La Niña. Also, the cyclonic wind anomalies are an atmospheric Kelvin wave response to diabatic cooling anomalies linked to both the decaying late fall negative Indian Ocean dipole (IOD) and winter atmospheric internal variability. Partially coupled experiments reveal that both the tropical Pacific air–sea coupling and atmospheric internal variability positively contribute to the coupled variability of the SCS CT, while the air–sea coupling over the tropical Indian Ocean weakens such variabilities. The northwest Pacific anticyclonic wind anomalies that usually precede El Niño–Southern Oscillation–independent negative IOD generated under the tropical Indian Ocean air–sea coupling undermine such variabilities.