Intraseasonal Variability of the Zonal-Mean Extratropical Tropopause: The Role of Changes in Polar Vortex Strength and Upper-Troposphere Wave Breaking
Intraseasonal Variability of the Zonal-Mean Extratropical Tropopause: The Role of Changes in Polar Vortex Strength and Upper-Troposphere Wave Breaking
复制标题
纬向平均温带对流层顶的季节内变化：极地涡旋强度和对流层上层波浪破碎的变化的作用
DOI：
10.1175/jas-d-15-0177.1
复制
发表时间：
2016
影响因子：
3.1
通讯作者：
P. Zurita‐Gotor
中科院分区：
文献类型：
--
作者：
Jesús Á. Barroso;P. Zurita‐Gotor
本文对北半球温带温带纬向平均对流层顶季节内时间尺度变率的主成分分析进行了研究。对流层顶的波状变形主导了这种变化，并比温带平均对流层顶高度的变化解释了更多的变化。第一模与纬向指数有很好的相关性。对流层顶模式的动力学演变分析表明，对流层顶变形是由平流层极涡中出现的对流层顶层异常波破裂引起的。具体地说，强烈(弱)极涡与极地对流层顶上升(下沉)有关，而在中纬度地区的异常波破裂导致偶极对流层顶变化，这与准地转位涡的异常经向涡通量是一致的。这两种强制在不同的时间尺度上运行，当以高频或低频对数据进行过滤时，它们可以被分开。巴..。
AbstractA principal component analysis of the Northern Hemisphere extratropical zonal-mean tropopause variability at intraseasonal time scales is presented in this work. Wavy deformations of the tropopause dominate this variability and explain significantly more variance than changes in the extratropical-mean tropopause height. The first mode is well correlated with the zonal index. Analysis of the dynamical evolution of the modes shows that tropopause deformations are caused by anomalous wave breaking at the tropopause level occurring in a preexisting anomalous stratospheric polar vortex. Specifically, an intense (weak) polar vortex is associated with a rising (sinking) of the polar tropopause, while anomalous wave breaking in the midlatitudes produces a dipolar tropopause change that is consistent with the anomalous meridional eddy flux of quasigeostrophic potential vorticity. These two forcings operate on different time scales and can be separated when the data are filtered at high or low frequency. Ba...