Midlatitude storms in a moister world: lessons from idealized baroclinic life cycle experiments
Midlatitude storms in a moister world: lessons from idealized baroclinic life cycle experiments
复制标题
潮湿世界中的中纬度风暴：理想化斜压生命周期实验的教训
DOI：
10.1007/s00382-012-1472-3
复制
发表时间：
2012
期刊：
影响因子：
4.6
通讯作者：
L. Polvani
中科院分区：
文献类型：
--
作者：
J. Booth;Shuguang Wang;L. Polvani
中纬度风暴对全球变暖的反应仍不确定。这在一定程度上是由于经向地表温度梯度减弱和低层水分含量升高的相互竞争的影响，预计这两者都是温室气体增加的结果。这里我们讨论后一种影响，并试图阐明湿度增加对中纬度风暴发展和演变的影响。我们通过一系列高度控制的斜压生命周期实验来做到这一点，其中大气湿度逐渐增加。为了评估结果的稳健性，水分含量以两种不同的方式改变：首先通过使用不同的初始相对湿度，其次通过改变我们插入克劳修斯-克拉珀龙方程的参数。后一种方法允许我们在保持相对湿度恒定的同时，人为地将水分含量增加到当前水平以上。无论湿度如何变化，我们发现几乎所有重要的风暴强度指标都随着湿度的增加而增加。具体来说，我们研究了风暴的中心气压最小值，最强的地面风，以及极端和累积降水率。就所有这些指标而言，湿度增加会产生更强的风暴。有趣的是，我们还发现，当湿度增加到超过当前水平时，由此产生的风暴水平尺度减小，而垂直范围增加。最后，我们注意到，对于与预计在21世纪末发生的水汽增加相当的情况，无论使用何种具体测量方法，风暴强度增加的实际幅度都相对较小。
The response of midlatitude storms to global warming remains uncertain. This is due, in part, to the competing effects of a weaker meridional surface temperature gradient and a higher low-level moisture content, both of which are projected to occur as a consequence of increasing greenhouse gases. Here we address the latter of these two effects, and try to elucidate the effect of increased moisture on the development and evolution of midlatitude storms. We do this with a set of highly controlled, baroclinic lifecycle experiments, in which atmospheric moisture is progressively increased. To assess the robustness of the results, the moisture content is changed in two different ways: first by using different initial relative humidity, and second by varying a parameter that we insert into the Clausius-Clapeyron equation. The latter method allows us to artificially increase the moisture content above current levels while keeping the relative humidity constant. Irrespective of how moisture is altered, we find that nearly all important measures of storm strength increase as the moisture content rises. Specifically, we examine the storm’s central pressure minimum, the strongest surface winds, and both extreme and accumulated precipitation rates. For all these metrics, increased moisture yields a stronger storm. Interestingly, we also find that when moisture is increased beyond current levels, the resulting storm has a reduced horizontal scale while its vertical extent increases. Finally, we note that for moisture increases comparable to those projected to occur by the end of the twentyfirst century, the actual amplitude of the increases in storm strength is relatively modest, irrespective of the specific measure one uses.
影响因子：
4.9
作者：
Catto, Jennifer L.;Shaffrey, Len C.;Hodges, Kevin I.
通讯作者：
Hodges, Kevin I.