Low Cloud–SST Feedback over the Subtropical Northeast Pacific and the Remote Effect on ENSO Variability
Low Cloud–SST Feedback over the Subtropical Northeast Pacific and the Remote Effect on ENSO Variability
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低云——东北太平洋副热带海温反馈及对 ENSO 变化的远程影响
DOI：
10.1175/jcli-d-21-0902.1
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发表时间：
2023
影响因子：
4.9
通讯作者：
Yen-Ting Hwang
中科院分区：
文献类型：
--
作者：
Liu Yang;Shang-Ping Xie;Samuel S. P. Shen;Jing-Wu Liu;Yen-Ting Hwang
摘要：低云频繁出现在副热带东北太平洋（NEP），并与当地海表温度（SST）相互作用，形成正反馈。风波动通过风-蒸发-SST（WES）反馈驱动SST变率，而地面蒸发也起到抑制SST的作用。本研究调查这些反馈的相对贡献NEP SST变率。在夏季NEP，低云SST反馈是如此之大，它超过了蒸发阻尼和放大夏季SST的变化。WES反馈导致局部增强的SST变率从NEP低云甲板向西南传播，在到达赤道时调制厄尔尼诺-南方涛动（ENSO）的发生。因此，在本发明中，当前期厄尔尼诺事件发生后，副热带NEP上空夏季有显著的暖SST异常时，第二年厄尔尼诺倾向于发生;当前期拉尼娜事件发生后，副热带NEP上空夏季有显著的冷SST异常时，第二年拉尼娜倾向于发生。共同体地球系统模型第1版（CESM 1）的锁定实验。当云-海耦合失效时，NEP上空SST变率减弱，对ENSO的调制作用消失。NEP低云-SST反馈对ENSO的非局地效应对气候预测具有重要意义。
Abstract.Low clouds frequent the subtropical northeastern Pacific Ocean (NEP) and interact with the local sea surface temperature (SST) to form positive feedback. Wind fluctuations drive SST variability through wind–evaporation–SST (WES) feedback, and surface evaporation also acts to damp SST. This study investigates the relative contributions of these feedbacks to NEP SST variability. Over the summer NEP, the low cloud–SST feedback is so large that it exceeds the evaporative damping and amplifies summertime SST variations. The WES feedback causes the locally enhanced SST variability to propagate southwestward from the NEP low cloud deck, modulating El Niño–Southern Oscillation (ENSO) occurrence upon reaching the equator. As a result, a second-year El Niño tends to occur when there are significant warm SST anomalies over the subtropical NEP in summer following an antecedent El Niño event and a second-year La Niña tends to occur when there are significant cold SST anomalies over the subtropical NEP in summer following an antecedent La Niña event The mediating role of the NEP low cloud–SST feedback is confirmed in a cloud-locking experiment with the Community Earth System Model, version 1 (CESM1). When the cloud–ocean coupling is disabled, SST variability over the NEP weakens and the modulating effect on ENSO vanishes. The nonlocal effect of the NEP low cloud–SST feedback on ENSO has important implications for climate prediction.