对长度为2500年的一个时间段中欧洲阿尔卑斯山的强降水事件所做的一个全面重建表明，发生洪涝频率高的时期往往与夏季气温低巧合。发表在本期Scientific Reports上的这项研究有可能帮助改进对气候变化条件下极端天气的预测。
中欧的夏季平均气温预计在全球气候变化下将会升高，同时夏季降水总量预计将会下降。洪涝发生频率的潜在增加还可能会增加受影响地区（包括阿尔卑斯山地区）的人类定居点、基础设施和人类生命所面临的风险。然而，预测极端气候（如强降水事件）的出现频率难度却要大一些。
Lukas Glur及同事对来自瑞士阿尔卑斯山区十个湖泊的沉积物进行了研究，他们用放射性碳分析方法确定了其年代。湖泊沉积物能准确反映过去的洪涝活动，因为它们能将各个事件记录为截然不同的沉积层。作者发现，洪涝在凉爽夏季发生频率往往更高，同时他们也提出，这种湿-冷天气一起出现的情况可能是由大西洋和地中海风暴路径的纬向偏移触发的。该研究提供的古气候观点可能会有助于更好了解全球气候变化怎样影响极端天气事件和改进对未来更温暖气候条件下洪涝风险的评估。（生物谷Bioon.com）
生物谷推荐的英文摘要
Scientific Reports doi:10.1038/srep02770
Frequent floods in the European Alps coincide with cooler periods of the past 2500 years
Lukas Glur，Stefanie B. Wirth，Ulf Buntgen，Adrian Gilli，Gerald H. Haug，Christoph Schar，Jurg Beer& Flavio S. Anselmetti
Severe floods triggered by intense precipitation are among the most destructive natural hazards in Alpine environments， frequently causing large financial and societal damage. Potential enhanced flood occurrence due to global climate change would thus increase threat to settlements， infrastructure， and human lives in the affected regions. Yet， projections of intense precipitation exhibit major uncertainties and robust reconstructions of Alpine floods are limited to the instrumental and historical period. Here we present a 2500-year long flood reconstruction for the European Alps， based on dated sedimentary flood deposits from ten lakes in Switzerland. We show that periods with high flood frequency coincide with cool summer temperatures. This wet-cold synchronism suggests enhanced flood occurrence to be triggered by latitudinal shifts of Atlantic and Mediterranean storm tracks. This paleoclimatic perspective reveals natural analogues for varying climate conditions， and thus can contribute to a better understanding and improved projections of weather extremes under climate change.
