Essential Ingredients to the Dynamics of Westerly Wind Bursts
Essential Ingredients to the Dynamics of Westerly Wind Bursts
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DOI：
10.1175/jcli-d-18-0584.1
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发表时间：
2019-09-01
影响因子：
4.9
通讯作者：
Tziperman, Eli
中科院分区：
文献类型：
--
作者：
Fu, Minmin;Tziperman, Eli
西风爆发（WWB）是发生在热带太平洋的短暂西风，它通过强迫海洋开尔文波而在ENSO动力学中发挥作用。它们与热带气旋，MJO和对流耦合Rossby波等大气现象有关，但其基本机制尚未得到很好的理解。我们研究WWBs使用一个aquaplanet大气环流模型，并发现，向东传播的对流加热模型WWBs的生成中起着关键作用，与以前的研究一致。此外，风引起的表面热交换（WISHE）的作用在一个短的时间尺度上约两天，显着放大模型WWB风接近事件的峰值。另一方面，发现辐射反馈（即，西风爆发引起的净辐射异常的变化）对WWB的发展并不是必需的，而是对WWB及其相关对流的弱负反馈。同样，感热通量异常也没有发现有模式WWBs的发展的影响。
Westerly wind bursts (WWBs) are brief, anomalously westerly winds in the tropical Pacific that play a role in the dynamics of ENSO through their forcing of ocean Kelvin waves. They have been associated with atmospheric phenomena such as tropical cyclones, the MJO, and convectively coupled Rossby waves, yet their basic mechanism is not yet well understood. We study WWBs using an aquaplanet general circulation model, and find that eastward-propagating convective heating plays a key role in the generation of model WWBs, consistent with previous studies. Furthermore, wind-induced surface heat exchange (WISHE) acts on a short time scale of about two days to dramatically amplify the model WWB winds near the peak of the event. On the other hand, it is found that radiation feedbacks (i.e., changes in the net radiative anomalies accompanying westerly wind bursts) are not essential for the development of WWBs, and act as a weak negative feedback on WWBs and their associated convection. Similarly, sensible surface heat flux anomalies are not found to have an effect on the development of model WWBs.