Detection of the secondary meridional circulation associated with the quasi‐biennial oscillation
Detection of the secondary meridional circulation associated with the quasi‐biennial oscillation
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DOI：
10.1029/2003jd004363
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发表时间：
2004-09
影响因子：
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通讯作者：
P. Ribera;C. Peña-Ortiz;R. Garcia-Herrera;D. Gallego;L. Gimeno;E. Hernández
中科院分区：
文献类型：
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作者：
P. Ribera;C. Peña-Ortiz;R. Garcia-Herrera;D. Gallego;L. Gimeno;E. Hernández
[1]利用美国国家环境预报中心（NCEP） 1958-2001年再分析资料，分析了平流层纬向和经向风场、温度场和位势高度场的准两年振荡（QBO）信号。多锥度法-奇异值分解（MTM-SVD）是一种多变量频域分析方法，用于检测显著和空间相干的窄带振荡。QBO是平流层纬向风中最强烈的信号。然后，利用MTM-SVD方法确定了QBO在平流层各层和各数据场的模式。与QBO相关的次级经向环流在获得的模式中被识别。这种环流的特征是与绝热上升（下沉）运动有关的负（正）温度异常，发生在东风（西风）切变区以及副热带和中纬度地区，而经向辐合和辐散水平被最大纬向风切变水平分隔开。这些垂直和经向运动在两个半球形成准对称的环流单元，尽管在南半球不那么强烈。
[1] The quasi-biennial oscillation (QBO) signal in stratospheric zonal and meridional wind, temperature, and geopotential height fields is analyzed based on the use of the National Centers for Environmental Prediction (NCEP) reanalysis (1958–2001). The multitaper method-singular value decomposition (MTM-SVD), a multivariate frequency domain analysis method, is used to detect significant and spatially coherent narrowband oscillations. The QBO is found as the most intense signal in the stratospheric zonal wind. Then, the MTM-SVD method is used to determine the patterns induced by the QBO at every stratospheric level and data field. The secondary meridional circulation associated with the QBO is identified in the obtained patterns. This circulation can be characterized by negative (positive) temperature anomalies associated with adiabatic rising (sinking) motions over zones of easterly (westerly) wind shear and over the subtropics and midlatitudes, while meridional convergence and divergence levels are found separated by a level of maximum zonal wind shear. These vertical and meridional motions form quasi-symmetric circulation cells over both hemispheres, though less intense in the Southern Hemisphere.