The Impact of the QBO on MJO Convection in Cloud-Resolving Simulations
The Impact of the QBO on MJO Convection in Cloud-Resolving Simulations
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云解析模拟中 QBO 对 MJO 对流的影响
DOI：
10.1175/jas-d-18-0179.1
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发表时间：
2019
影响因子：
3.1
通讯作者：
A. Sobel
中科院分区：
文献类型：
--
作者：
Z. Martin;Shuguang Wang;J. Nie;A. Sobel
本文在一个参数化的大尺度动力学有限区域云分辨模式中研究了Madden-Julian振荡（MJO）和平流层准两年振荡（QBO）之间的关系。该模型被用来模拟两个连续的MJO事件发生在2011年秋末和初冬。为了测试QBO对模拟MJO事件的影响，通过添加特征风和温度异常来施加各种QBO状态。在实验中，只有QBO温度异常强加（没有相应的纬向风异常）的对流强度在MJO活跃阶段被放大的QBO东风阶段[一个异常冷的热带对流层顶（TTL）]相比，西风QBO阶段（温暖的TTL），作为测量向外长波辐射，云分数，和大规模的上升。该响应与所观察到的MJO-QBO关系定性一致。降水的响应较弱，并且在模拟配置的变化中不太一致。实验中只施加QBO风异常（没有相应的温度异常）显示出比施加温度异常的影响要弱得多，这表明TTL温度异常是QBO调制MJO的关键途径。敏感性试验表明，QBO对MJO对流的影响取决于QBO温度异常的幅度和高度：低海拔和大幅度的温度异常对MJO对流的影响更为显著。
This study examines the relationship between the Madden–Julian oscillation (MJO) and the stratospheric quasi-biennial oscillation (QBO) in a limited-area cloud-resolving model with parameterized large-scale dynamics. The model is used to simulate two consecutive MJO events that occurred during the late fall and early winter of 2011. To test the influence of the QBO on the simulated MJO events, various QBO states are imposed via the addition of characteristic wind and temperature anomalies. In experiments with only QBO temperature anomalies imposed (without corresponding zonal wind anomalies) the strength of convection during MJO active phases is amplified for the QBO easterly phase [an anomalously cold tropical tropopause layer (TTL)] compared to the westerly QBO phase (a warm TTL), as measured by outgoing longwave radiation, cloud fraction, and large-scale ascent. This response is qualitatively consistent with the observed MJO–QBO relationship. The response of precipitation is weaker, and is less consistent across variations in the simulation configuration. Experiments with only imposed QBO wind anomalies (without corresponding temperature anomalies) show much weaker effects altogether than those with imposed temperature anomalies, suggesting that TTL temperature anomalies are a key pathway through which the QBO can modulate the MJO. Sensitivity tests indicate that the QBO influence on MJO convection depends on both the amplitude and the height of the QBO temperature anomaly: lower-altitude and larger-amplitude temperature anomalies have more pronounced effects on MJO convection.
影响因子：
6.8
作者：
Crueger, Traute;Stevens, Bjorn
通讯作者：
Stevens, Bjorn