Increase in the skewness of extratropical vertical velocities with climate warming: fully nonlinear simulations versus moist baroclinic instability
Increase in the skewness of extratropical vertical velocities with climate warming: fully nonlinear simulations versus moist baroclinic instability
复制标题
随着气候变暖，温带垂直速度的偏度增加：完全非线性模拟与湿斜压不稳定性
DOI：
10.1002/qj.3195
复制
发表时间：
2018
影响因子：
8.9
通讯作者：
Martin S. Singh
中科院分区：
文献类型：
--
作者：
P. O’Gorman;T. Merlis;Martin S. Singh
在对流层外的垂直速度分布是倾斜的，这样向上的运动比向下的运动快。这种偏态对降水强度分布和湿涡旋的有效静稳定度都很重要。在这里，我们表明，在模拟与理想化的大气环流模式（GCM），除了在非常温暖的气候，随着气候变暖的垂直速度的偏度增加的幅度。偏度随着变暖而增加，这与湿斜压不稳定性的研究是一致的，该研究表明，在温暖的气候中，当层结接近湿中性时，上升气流的面积应该收缩。然而，偏度的增加与变暖是弱得多的完全非线性模拟相比，发现在同一GCM的湿斜压不稳定的不稳定模式。在温暖的气候中，非线性平衡到宏观湍流状态导致偏态的减少。因此，虽然不稳定的模式可能是相关的一些情况下的气旋，他们高估了变暖的垂直速度的整体分布的偏度的影响。值得注意的是，在足够高的温度下，最不稳定的模式从准周期波转变为孤立的非绝热Rossby涡旋，这可能意味着温暖气候中快速增长的扰动。
The distribution of vertical velocities in the extratropical troposphere is skewed such that upward motions are faster than downward motions. This skewness is important for the intensity distribution of precipitation and for the effective static stability experienced by moist eddies. We show here that the skewness of the vertical velocity increases in magnitude as the climate warms in simulations with an idealized general circulation model (GCM), except in very warm climates. That the skewness increases with warming is consistent with studies of moist baroclinic instability which suggest that the area of updraughts should contract as the stratification approaches moist neutrality in warm climates. However, the increase in skewness with warming is much weaker in the fully nonlinear simulations as compared to what is found for unstable modes of moist baroclinic instability in the same GCM. Nonlinear equilibration to a macroturbulent state leads to a reduction in skewness in warm climates. Therefore, while the unstable modes may be relevant for some cases of cyclogenesis, they overestimate the effect of warming on the skewness of the overall distribution of the vertical velocity. Remarkably, the most unstable mode transitions from a quasi‐periodic wave to an isolated diabatic Rossby vortex at sufficiently high temperatures, with possible implications for fast‐growing disturbances in warm climates.
影响因子：
8.9
作者：
J. Chagnon;S. Gray;J. Methven
通讯作者：
J. Chagnon;S. Gray;J. Methven
使用罗斯贝波分量解释具有水分参数化效应的斜斜波
影响因子：
3.1
作者：
Frame T
通讯作者：
Frame T