Modulation of the MJO and North Pacific Storm Track Relationship by the QBO
Modulation of the MJO and North Pacific Storm Track Relationship by the QBO
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DOI：
10.1029/2017jd027977
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发表时间：
2018-04
期刊：
影响因子：
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通讯作者：
Jiabao Wang;Hyemi Kim;E. Chang;S. Son
中科院分区：
文献类型：
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作者：
Jiabao Wang;Hyemi Kim;E. Chang;S. Son
这项研究表明，准两年振荡（QBO）可能对1979-2016年期间10月至3月期间与Madden-Julian振荡（MJO）相关的北太平洋风暴轴（NPST）变化产生影响。NPST显示出显着的季节内变化，以响应MJO。一般来说，当MJO对流位于印度洋（太平洋西部到中部）时，NPST倾向于向南移。这种与MJO相关的NPST变化在QBO的东风阶段（EQBO）比在西风阶段（WQBO）具有更大的幅度。这种NPST变化的空间分布也表现出显着的差异，在两个QBO阶段的纬向拉长的模式在EQBO冬季，但分为两个中心在WQBO冬季。对NPST变化的动力过程分析表明，斜压能量转换和下游能量传播起主导作用。季节内气流变化的分析表明，北太平洋MJO相关的斜压性幅度较大。这可能是由于在EQBO冬季，MJO和相关的Rossby波源较强，这可能会导致NPST变化幅度的增强。另一方面，NPST变化的不同空间分布可能是QBO对NPST直接影响的结果。这些结果表明，QBO的影响需要考虑更好地再现MJO-NPST遥相关的大气环流模式，这也可能有利于亚季节预测的热带风暴活动。
This study demonstrates a possible impact of the quasi‐biennial oscillation (QBO) on the Madden‐Julian Oscillation (MJO)‐related North Pacific storm track (NPST) change during October–March for the period of 1979–2016. The NPST shows significant intraseasonal changes in response to the MJO. In general, when the MJO convection is located over the Indian Ocean (western to central Pacific), the NPST tends to shift poleward (southward). This MJO‐related NPST change has larger amplitude during the easterly phase of the QBO (EQBO) than during its westerly phase (WQBO). The spatial distribution of this NPST change also exhibits significant differences between the two QBO phases with a zonally elongated pattern during EQBO winters but separated into two centers during WQBO winters. Diagnoses of the dynamical processes associated with the NPST change indicate the dominant roles of the baroclinic energy conversion and downstream energy propagation. The analysis of intraseasonal flow change indicates a larger amplitude of the MJO‐related baroclinicity over the North Pacific. This is likely due to a stronger MJO and associated Rossby wave source in EQBO winters, which may give rise to the enhanced amplitude of the NPST change. On the other hand, different spatial distribution of the NPST change is likely a result of a direct impact of the QBO on the NPST. These results suggest that the QBO impact needs to be considered for better reproduction of the MJO‐NPST teleconnection in general circulation models, which may also benefit subseasonal prediction of extratropical storm activities.