Indo-Western Pacific Climate Variability: ENSO Forcing and Internal Dynamics in a Tropical Pacific Pacemaker Simulation
Indo-Western Pacific Climate Variability: ENSO Forcing and Internal Dynamics in a Tropical Pacific Pacemaker Simulation
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DOI：
10.1175/jcli-d-18-0203.1
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发表时间：
2018-11
影响因子：
4.9
通讯作者：
Chuan-Yang Wang;S. Xie;Y. Kosaka
中科院分区：
文献类型：
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作者：
Chuan-Yang Wang;S. Xie;Y. Kosaka
厄尔尼诺-南方涛动（ENSO）在北方冬季达到峰值，但它对印度-西太平洋气候的影响持续了另外两个季节。使用太平洋-全球大气（POGA）实验与耦合的大气环流模式，热带太平洋海表温度（SST）的异常恢复遵循的观测，而大气和海洋是完全耦合的其他地方的ENSO效应的关键海洋-大气相互作用过程进行了研究。POGA在模拟厄尔尼诺现象后的春季和夏季热带印度洋ENSO强迫变暖和热带太平洋西北部异常反气旋环流模式方面显示了技能。10个成员POGA集合允许分解成ENSO强迫和ENSO无关（内部）组件的印度-西太平洋的变化。内部变率在幅度上与ENSO强迫相当，并且与ENSO振幅和相位无关。随机内部变率导致明显的年代际调制的ENSO相关性在印度-西太平洋，这是高ENSO方差的时期。这与最近研究中记录的过去130年的仪器观测结果大致一致。内部变率的特点是海平面压力模式，延伸到北印度洋，并与连贯的SST异常从阿拉伯海到西太平洋，暗示海洋-大气耦合。
El Niño–Southern Oscillation (ENSO) peaks in boreal winter but its impact on Indo-western Pacific climate persists for another two seasons. Key ocean–atmosphere interaction processes for the ENSO effect are investigated using the Pacific Ocean–Global Atmosphere (POGA) experiment with a coupled general circulation model, where tropical Pacific sea surface temperature (SST) anomalies are restored to follow observations while the atmosphere and oceans are fully coupled elsewhere. The POGA shows skills in simulating the ENSO-forced warming of the tropical Indian Ocean and an anomalous anticyclonic circulation pattern over the northwestern tropical Pacific in the post–El Niño spring and summer. The 10-member POGA ensemble allows decomposing Indo-western Pacific variability into the ENSO forced and ENSO-unrelated (internal) components. Internal variability is comparable to the ENSO forcing in magnitude and independent of ENSO amplitude and phase. Random internal variability causes apparent decadal modulations of ENSO correlations over the Indo-western Pacific, which are high during epochs of high ENSO variance. This is broadly consistent with instrumental observations over the past 130 years as documented in recent studies. Internal variability features a sea level pressure pattern that extends into the north Indian Ocean and is associated with coherent SST anomalies from the Arabian Sea to the western Pacific, suggestive of ocean–atmosphere coupling.