Quasi‐Biennial Oscillation of Short‐Period Planetary Waves and Polar Night Jet in Winter Antarctica Observed in SABER and MERRA‐2 and Mechanism Study With a Quasi‐Geostrophic Model
Quasi‐Biennial Oscillation of Short‐Period Planetary Waves and Polar Night Jet in Winter Antarctica Observed in SABER and MERRA‐2 and Mechanism Study With a Quasi‐Geostrophic Model
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DOI：
10.1029/2019gl084759
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发表时间：
2019-11
影响因子：
5.2
通讯作者：
Xian Lu;Haonan Wu;X. Chu;J. Oberheide;M. Mlynczak;J. Russell
中科院分区：
文献类型：
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作者：
Xian Lu;Haonan Wu;X. Chu;J. Oberheide;M. Mlynczak;J. Russell
利用SABER资料分析了2003-2018年大气探空资料，发现2-5d向东传播行星波的年际变化与南半球冬季平均67.5°±10°S纬向风呈正相关，与准两年振荡指数呈负相关。QBOe的合成平均波幅比QBOw的大约20%。在统计平均值上，QBOE期间极地夜间急流(PNJ)的极侧加强和赤道侧减弱形成偶极子环流型。相比之下，在之前用Holton-Tan理论解释的北半球纬向平均纬向风(1月)中，只有一个负值环流。这种差异意味着两个半球之间的不对称，以及解释南极洲额外的阳性细胞所需的其他过程。机制模拟表明，较强的PNJ在QBOe中产生了比QBOw更大的向东传播的行星波(更强的波)，解释了南极行星波中的类QBO信号。
Analyzing Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations from 2003 to 2018, the interannual variability of 2–5d eastward propagating planetary waves is found to correlate positively with zonal‐mean zonal winds averaged over 67.5°±10°S but negatively with the quasi‐biennial oscillation (QBO) index in austral winter. The composite‐mean wave amplitudes are ~20% larger in QBOe than in QBOw. On statistical average, the poleward flank strengthening and the equatorward flank weakening of polar night jet (PNJ) during QBOe form a dipole‐cell pattern. In contrast, only a single negative cell is seen in the Northern Hemisphere zonal‐mean zonal winds (January) previously explained by the Holton‐Tan theory. Such difference implies an interhemispheric asymmetry and other processes needed to explain the additional positive cell in Antarctica. Mechanistic modeling illustrates that the stronger PNJ generates eastward propagating planetary waves with larger growth rates (stronger waves) in QBOe than QBOw, explaining the QBO‐like signal in the Antarctic planetary waves.