Future changes in atmospheric rivers and their implications for winter flooding in Britain
Future changes in atmospheric rivers and their implications for winter flooding in Britain
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DOI：
10.1088/1748-9326/8/3/034010
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发表时间：
2013-07-01
影响因子：
6.7
通讯作者：
Wade, Andrew J.
中科院分区：
文献类型：
--
作者：
Lavers, David A.;Allan, Richard P.;Wade, Andrew J.
在温带气旋的温暖传送带内，大气河流（AR）是关键的天气特征，它提供了大部分向极地的水汽输送，并与强降雨和长时间降雨有关。 ARs 造成了中纬度地区许多最严重的冬季洪水，造成了重大的社会经济损失；例如，英国 2012 年夏季/冬季洪水造成的损失估计约为 16 亿美元。鉴于当前 AR 与河流峰值流量之间已确立的联系，评估 AR 在未来气候预测下如何做出反应对于衡量未来洪水的影响非常重要。我们表明，在第五个气候模型比对项目 (CMIP5) 中五个最先进的全球气候模型 (GCM) 的多重模拟的未来情景中，北大西洋 AR 预计将变得更强、数量更多。预计 AR 中水蒸气输送的增加意味着降雨总量增加的风险更大，因此英国冬季洪水规模更大，AR 频率增加导致更多洪水事件。在 2074-2099 年的高排放情景 (RCP8.5) 中，五个 GCM 中的 AR 频率大约翻倍。我们的结果表明，预计 AR 的变化主要是对人为辐射强迫引起的变暖的热力学响应。
Within the warm conveyor belt of extra-tropical cyclones, atmospheric rivers (ARs) are the key synoptic features which deliver the majority of poleward water vapour transport, and are associated with episodes of heavy and prolonged rainfall. ARs are responsible for many of the largest winter floods in the mid-latitudes resulting in major socioeconomic losses; for example, the loss from United Kingdom (UK) flooding in summer/winter 2012 is estimated to be about $1.6 billion in damages. Given the well-established link between ARs and peak river flows for the present day, assessing how ARs could respond under future climate projections is of importance in gauging future impacts from flooding. We show that North Atlantic ARs are projected to become stronger and more numerous in the future scenarios of multiple simulations from five state-of-the-art global climate models (GCMs) in the fifth Climate Model Intercomparison Project (CMIP5). The increased water vapour transport in projected ARs implies a greater risk of higher rainfall totals and therefore larger winter floods in Britain, with increased AR frequency leading to more flood episodes. In the high emissions scenario (RCP8.5) for 2074-2099 there is an approximate doubling of AR frequency in the five GCMs. Our results suggest that the projected change in ARs is predominantly a thermodynamic response to warming resulting from anthropogenic radiative forcing.