Variability in QBO Temperature Anomalies on Annual and Decadal Time Scales
Variability in QBO Temperature Anomalies on Annual and Decadal Time Scales
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DOI：
10.1175/jcli-d-20-0287.1
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发表时间：
2020-10
影响因子：
4.9
通讯作者：
Z. Martin;A. Sobel;A. Butler;Shuguang Wang
中科院分区：
文献类型：
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作者：
Z. Martin;A. Sobel;A. Butler;Shuguang Wang
平流层准两年生振荡（QBO）引起平流层下层和热带对流层顶层（TTL）温度异常，平流层下层风偏东风时温度偏冷，西风时温度偏暖。最近的文献表明，这些QBO温度异常在影响热带对流层方面具有潜在的重要意义，特别是在解释QBO与Madden-Julian涛动（MJO）之间的关系方面。作者利用再分析和观测数据集研究了QBO温度异常在几个时间尺度上的变异性。作者发现，在冬季，相对于其他季节，赤道上的QBO温度异常明显更强（即QBO东风相较冷，QBO西风相较暖），而赤道外的温度异常较弱。赤道和亚热带的变化补偿了经向温度梯度，因此（通过热风平衡）赤道纬向风异常的幅度不像温度异常那样变化。在年代际时间尺度上发现了同样的赤道上较强和赤道外较弱的QBO温度异常模式：与1979 - 1999年相比，1999-2019年的异常更强。这些变化对QBO温度异常的原因，以及它们与MJO-QBO关系的可能相关性，尚不清楚。
The stratospheric quasi-biennial oscillation (QBO) induces temperature anomalies in the lower stratosphere and tropical tropopause layer (TTL) that are cold when lower-stratospheric winds are easterly and warm when winds are westerly. Recent literature has indicated that these QBO temperature anomalies are potentially important in influencing the tropical troposphere, and particularly in explaining the relationship between the QBO and the Madden–Julian oscillation (MJO). The authors examine the variability of QBO temperature anomalies across several time scales using reanalysis and observational datasets. The authors find that, in boreal winter relative to other seasons, QBO temperature anomalies are significantly stronger (i.e., colder in the easterly phase of the QBO and warmer in the westerly phase of the QBO) on the equator, but weaker off the equator. The equatorial and subtropical changes compensate such that meridional temperature gradients and thus (by thermal wind balance) equatorial zonal wind anomalies do not vary in amplitude as the temperature anomalies do. The same pattern of stronger on-equatorial and weaker off-equatorial QBO temperature anomalies is found on decadal time scales: stronger anomalies are seen for 1999–2019 compared to 1979–99. The causes of these changes to QBO temperature anomalies, as well as their possible relevance to the MJO–QBO relationship, are not known.