Enhanced poleward propagation of storms under climate change
Enhanced poleward propagation of storms under climate change
复制标题
DOI：
10.1038/s41561-017-0001-8
复制
发表时间：
2017-11
影响因子：
18.3
通讯作者：
T. Tamarin-Brodsky;Y. Kaspi
中科院分区：
文献类型：
--
作者：
T. Tamarin-Brodsky;Y. Kaspi
地球中纬度地区主要是大气天气变化较大的地区-通常被称为风暴路径-这影响了温带外地区的温度、降水和风的分布。温室气体排放增加所迫使的综合气候模型表明，在全球变暖的情况下，风暴路径向极地移动。虽然极地移动在大多数模型中都是一种强有力的反应，但目前对于潜在的动力机制是什么，还没有达成共识。在这里，我们提出了一种关于极地移动的新视角，这是基于风暴路径的拉格朗日观点。结果表明，在全球变暖的情况下，除了风暴发生纬度的极移和斜压性的改变外，气旋风暴的纬向位移也在增加。这是通过将风暴跟踪算法应用于CMIP5模型的集合来实现的。气候变暖时纬向传播的增加是高空风增强和大气水汽增加的结果。风暴传播特征的这些变化可能会对中纬度气候产生重大影响。
Earth’s midlatitudes are dominated by regions of large atmospheric weather variability—often referred to as storm tracks— which influence the distribution of temperature, precipitation and wind in the extratropics. Comprehensive climate models forced by increased greenhouse gas emissions suggest that under global warming the storm tracks shift poleward. While the poleward shift is a robust response across most models, there is currently no consensus on what the underlying dynamical mechanism is. Here we present a new perspective on the poleward shift, which is based on a Lagrangian view of the storm tracks. We show that in addition to a poleward shift in the genesis latitude of the storms, associated with the shift in baroclinicity, the latitudinal displacement of cyclonic storms increases under global warming. This is achieved by applying a storm-tracking algorithm to an ensemble of CMIP5 models. The increased latitudinal propagation in a warmer climate is shown to be a result of stronger upper-level winds and increased atmospheric water vapour. These changes in the propagation characteristics of the storms can have a significant impact on midlatitude climate.