QBO modulation of the semiannual oscillation in MAECHAM5 and HAMMONIA
QBO modulation of the semiannual oscillation in MAECHAM5 and HAMMONIA
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MAECHAM5 和 HAMMONIA 中半年振荡的 QBO 调制
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
M. Keller
中科院分区：
文献类型：
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作者：
C. Peña;H. Schmidt;M. Giorgetta;M. Keller
[1]利用MAECHAM5和HAMMONIA大气环流模式分析了赤道平流层上部和中层准两年振荡（QBO）特征。结果表明，这一区域受到平流层QBO的显著影响。在平流层上部，QBO调制平流层半年振荡（SSAO）西风位相的最大下降高度。我们的研究结果还表明，QBO调制的高度最大的下降，也是强度的SSAO东风阶段。我们探讨的作用，大规模和小规模的波，也动量平流的QBO签名在SSAO域的强迫。结果表明，QBO信号向中层中上层的垂直传播依赖于SAO的垂直位相结构，从而依赖于季节循环。在二至日，当MSAO西风盛行于中层中上部时，在平流层顶区上空没有QBO信号。然而，在春分，当MSAO东风主导的中层和上层，QBO签名延伸到整个中层和低热层。准两年振荡直接调制MSAO东风通过修改高度，在那里他们是在上层中层产生的。QBO签名也检测到的MSAO西风相位发生在中层顶区域在春分。
[1] The quasi-biennial oscillation (QBO) signature in the equatorial upper stratosphere and mesosphere is analyzed from MAECHAM5 and HAMMONIA general circulation models. Our results show that this region is significantly influenced by the stratospheric QBO. In the upper stratosphere the QBO modulates the altitude of maximum descent of the stratospheric semiannual oscillation (SSAO) westerly phases. Our results also suggest that the QBO modulates the altitude of maximum descent and also the strength of the SSAO easterly phase. We explore the role of large-scale and small-scale waves and also momentum advection in the forcing of the QBO signature in the SSAO domain. The results show how the vertical propagation of the QBO signature to the middle and upper mesosphere depends on the vertical phase structure of the SAO and consequently on the seasonal cycle. During the solstices when MSAO westerlies prevail in the middle and upper mesosphere no QBO signature can be detected above the stratopause region. However, during the equinoxes, when MSAO easterlies dominate in the middle and upper mesosphere, the QBO signature extends throughout the mesosphere and low thermosphere. The QBO directly modulates MSAO easterlies by modifying the altitude at which they are generated in the upper mesosphere. A QBO signature is also detected on the MSAO westerly phase occurring in the mesopause region during the equinoxes.