Observed and Simulated Teleconnections Between the Stratospheric Quasi-Biennial Oscillation and Northern Hemisphere Winter Atmospheric Circulation
Observed and Simulated Teleconnections Between the Stratospheric Quasi-Biennial Oscillation and Northern Hemisphere Winter Atmospheric Circulation
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DOI：
10.1029/2018jd029368
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发表时间：
2019-02-16
影响因子：
4.4
通讯作者：
Schenzinger, Verena
中科院分区：
文献类型：
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作者：
Andrews, Martin B.;Knight, Jeff R.;Schenzinger, Verena
准两年振荡（Quasi-Biennial Oscillation，QBO）是热带平流层年际变化的主要模态，东、西风纬向风场在大约28个月的时间内交替变化。它似乎影响了北方半球冬季平流层极涡和地球表面附近的大气环流。然而，短暂的观测记录使得这些表面连接的明确识别具有挑战性。为了克服这一点，我们使用一个多世纪的控制模拟的气候模式与现实的，自发产生的QBO检查遥相关与extratroupal冬季地面压力模式。利用QBO的30 hPa指数，我们证明了观测到的与北极涛动（AO）的遥相关可能是真实的，与北大西洋涛动（NAO）的遥相关是可能的，但不确定。模拟的QBO-AO遥相关是强大的，但似乎比观测弱。尽管如此，与观测记录的不一致性不能正式证明。为了评估我们的结果的鲁棒性，我们使用QBO的替代措施，它选择QBO相位与西风或东风延伸到更广泛的高度范围比单级指数选择的相位。我们发现AO和NAO响应的强度和意义都有所增加，并且更好地再现了所观察到的表面遥相关模式。此外，这种QBO度量揭示了模拟的AO响应确实可能比观察到的要弱。我们的结论是，QBO可以提供另一个潜在的技术来源，北方半球冬季预测，如果它的地面遥相关可以准确地模拟。
The Quasi-Biennial Oscillation (QBO) is the dominant mode of interannual variability in the tropical stratosphere, with easterly and westerly zonal wind regimes alternating over a period of about 28months. It appears to influence the Northern Hemisphere winter stratospheric polar vortex and atmospheric circulation near the Earth's surface. However, the short observational record makes unequivocal identification of these surface connections challenging. To overcome this, we use a multicentury control simulation of a climate model with a realistic, spontaneously generated QBO to examine teleconnections with extratropical winter surface pressure patterns. Using a 30-hPa index of the QBO, we demonstrate that the observed teleconnection with the Arctic Oscillation (AO) is likely to be real, and a teleconnection with the North Atlantic Oscillation (NAO) is probable, but not certain. Simulated QBO-AO teleconnections are robust, but appear weaker than in observations. Despite this, inconsistency with the observational record cannot be formally demonstrated. To assess the robustness of our results, we use an alternative measure of the QBO, which selects QBO phases with westerly or easterly winds extending over a wider range of altitudes than phases selected by the single-level index. We find increased strength and significance for both the AO and NAO responses, and better reproduction of the observed surface teleconnection patterns. Further, this QBO metric reveals that the simulated AO response is indeed likely to be weaker than observed. We conclude that the QBO can potentially provide another source of skill for Northern Hemisphere winter prediction, if its surface teleconnections can be accurately simulated.