Record Balkan floods of 2014 linked to planetary wave resonance.
Record Balkan floods of 2014 linked to planetary wave resonance.
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DOI：
10.1126/sciadv.1501428
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发表时间：
2016-04
期刊：
影响因子：
13.6
通讯作者：
Rahmstorf S
中科院分区：
文献类型：
--
作者：
Stadtherr L;Coumou D;Petoukhov V;Petri S;Rahmstorf S
大气共振波减慢了气旋的移动速度，导致巴尔干地区连续四天出现强降雨。 2014年5月，巴尔干地区遭受Vb型气旋袭击，给波斯尼亚和黑塞哥维那、塞尔维亚和克罗地亚带来了灾难性的洪水和严重破坏。 Vb 气旋从地中海迁移到北部，在那里它们吸收温暖和潮湿的空气，经常在中欧/东欧造成洪水。全球范围内的极端降雨事件正在增加，热力学和动力学机制都发挥了作用。在热力学方面通常得到很好理解的情况下，当前和未来的动力学变化存在很大的不确定性。我们研究影响巴尔干地区灾难性洪水的气候和气象因素，重点关注大规模环流。我们发现，Vb 气旋异常静止，连续几天带来极端降雨，这种情况可能与准静止环球罗斯贝波列有关。我们提供的证据表明这种准稳态波被波谐振放大。对巴尔干地区春季每日降雨量的统计分析显示，1950 年至 2014 年期间，降雨量呈显着上升趋势，特别是在与洪水事件相关的高分位数中。这些变化不能用简单的热力学论据来解释，因此我们认为动力学过程可能在增加巴尔干地区洪水风险方面发挥了作用。
Resonating atmospheric waves slowed down a cyclone’s movement, leading to four successive days of heavy rainfall over the Balkans. In May 2014, the Balkans were hit by a Vb-type cyclone that brought disastrous flooding and severe damage to Bosnia and Herzegovina, Serbia, and Croatia. Vb cyclones migrate from the Mediterranean, where they absorb warm and moist air, to the north, often causing flooding in central/eastern Europe. Extreme rainfall events are increasing on a global scale, and both thermodynamic and dynamical mechanisms play a role. Where thermodynamic aspects are generally well understood, there is large uncertainty associated with current and future changes in dynamics. We study the climatic and meteorological factors that influenced the catastrophic flooding in the Balkans, where we focus on large-scale circulation. We show that the Vb cyclone was unusually stationary, bringing extreme rainfall for several consecutive days, and that this situation was likely linked to a quasi-stationary circumglobal Rossby wave train. We provide evidence that this quasi-stationary wave was amplified by wave resonance. Statistical analysis of daily spring rainfall over the Balkan region reveals significant upward trends over 1950–2014, especially in the high quantiles relevant for flooding events. These changes cannot be explained by simple thermodynamic arguments, and we thus argue that dynamical processes likely played a role in increasing flood risks over the Balkans.