低频风应力强迫减弱数值模式中厄尔尼诺多样性

Low-frequency wind stress forcing reduces El Ni?o diversity in numerical model

厄尔尼诺-南方涛动(El Nino-Southern Oscillation,ENSO)包括低频海-气耦合和高频过程,但ENSO动力学中的非线性阻碍了两者对ENSO发展贡献的定量分析。最近的一项工作提出了在线低通滤波技术,通过去除模型中海-气耦合过程中风应力的高频部分,从而研究低频海-气相互作用对ENSO动力学的影响。本文通过比较使用和不使用在线低通滤波模块的模式,发现去除高频风力后会延长ENSO的周期,并降低厄尔尼诺现象的多样性,这证实了高频过程在厄尔尼诺多样性的成因中起着至关重要的作用。

The El Ni?o-Southern Oscillation(ENSO)includes both low-frequency ocean-atmosphere coupling and high-frequency processes,yet the nonlinearity in ENSO dynamics prevents any quantitative estimation of the contributions of the two to ENSO development.The online low-frequency filtering technique was proposed in a recent work to exclude the high-frequency part of wind stress during ocean-atmosphere coupling in model,thus can be used to scale the impact of low-frequency ocean-atmosphere interaction on the ENSO dynamics.By comparing model simulations with and without the online low-pass filtering module,we found that removing the high-frequency wind forcing prolongs ENSO period and decreases El Ni?o diversity.The results confirm that the high-frequency momentum processes play a crucial role in the genesis of El Ni?o diversity.