Baroclinic instability at the winter stratopause
Baroclinic instability at the winter stratopause
复制标题
冬季平流层顶的斜压不稳定性
DOI：
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发表时间：
1974
期刊：
影响因子：
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通讯作者：
A. Simmons
中科院分区：
文献类型：
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作者：
A. Simmons
斜压不稳定性在冬季平流层顶的理想模式中得到检验。平流层上层比中层下层分层更稳定，当纬向气流有西风切变时，会发生不稳定。利用有代表性的参数值，对纬向波长4000 km、垂直尺度10 km、移动速度在平流层顶纬向风2ms−1以内的扰动，发现最大加倍时间为2天。牛顿冷却使生长速率降低了约80%的阻尼速率，这对于小于7天的弛豫时间非常重要。
Baroclinic instability is examined in an idealized model of the winter stratopause. The upper stratosphere is more stably stratified than the lower mesosphere, and instability can occur when the zonal flow has westerly shear., Using representative parameter values, a maximum doubling time of 2 days is found for a disturbance with zonal wavelength 4000 km and vertical scale 10 km, moving with a velocity within 2ms−1 of that of the zonal wind at the stratopause. Newtonian cooling reduces growth-rates by some 80% of the damping rate, and becomes important for relaxation times of less than 7 days.