Baroclinic Characteristics and Energetics of Annual Rossby Waves in the Southern Tropical Indian Ocean
Baroclinic Characteristics and Energetics of Annual Rossby Waves in the Southern Tropical Indian Ocean
复制标题
南热带印度洋年度罗斯贝波的斜压特征和能量
DOI：
10.1175/jpo-d-19-0294.1
复制
发表时间：
2020
影响因子：
3.5
通讯作者：
Yao Jinglong
中科院分区：
文献类型：
--
作者：
Huang Ke;Wang Dongxiao;Feng Ming;Han Weiqing;Chen Gengxin;Sun Chaojiao;Zhang Xiaolin;Xie Qiang;Wang Weiqiang;Liu Qinyan;Yao Jinglong
第一斜压模态Rossby波对热带南印度洋（STIO; 0°-20 ° S，50°-115 ° E）海平面年变率有重要影响。通过对连续层结线性海洋模式的分析，发现第二斜压模态对海平面年变率也有显著的贡献（高达第一斜压模态的81%）。低阶斜压Rossby波（第一、二阶）的叠加对STIO海平面变率的高能中心（~10°S）和季节温跃层下的垂直能量穿透贡献很大。结果表明，低阶BRW具有较长的纬向波长和较弱的阻尼，与局地大尺度风强迫的耦合比高阶BRW更有效; Ekman抽运的纬向相干性导致低阶BRW的纬向能量最大。总体而言，本研究扩展了传统的分析，建议在解释STIO的年变率时需要考虑第二斜压模态的特征。
The first baroclinic mode Rossby wave is known to be of critical importance to the annual sea level variability in the southern tropical Indian Ocean (STIO; 0°–20°S, 50°–115°E). In this study, an analysis of continuously stratified linear ocean model reveals that the second baroclinic mode also has significant contribution to the annual sea level variability (as high as 81% of the first baroclinic mode). The contributions of residual high-order modes (3 ≤n≤ 25) are much less. The superposition of low-order (first and second) baroclinic Rossby waves (BRWs) primarily contribute to the high energy center of sea level variability at ~10°S in the STIO and the vertical energy penetration below the seasonal thermocline. We have found that 1) the low-order BRWs, having longer zonal wavelengths and weaker damping, can couple more efficiently to the local large-scale wind forcing than the high-order modes and 2) the zonal coherency of the Ekman pumping results in the latitudinal energy maximum of low-order BRWs. Overall, this study extends the traditional analysis to suggest the characteristics of the second baroclinic mode need to be taken into account in interpreting the annual variability in the STIO.