Variability of extreme precipitation over Europe and its relationships with teleconnection patterns
Variability of extreme precipitation over Europe and its relationships with teleconnection patterns
复制标题
DOI：
10.5194/hess-18-709-2014
复制
发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Gonzalez-Reviriego, N.
中科院分区：
文献类型：
--
作者：
Casanueva, A.;Rodriguez-Puebla, C.;Gonzalez-Reviriego, N.
由于全球气候变化对水文循环的影响，以及对自然系统高于平均气候值的威胁，科学界对极端降水的兴趣日益浓厚。了解降水指数的变化及其与大气过程的关联有助于预测极端事件的频率和严重程度。本文评估了三个降水极端值的趋势：连续干/湿天数（CDD/CWD）以及日降水量超过参考期第95个百分位数的天数降水量与总降水量（或极湿天数的贡献，R95pTOT）的商。这项研究的目的是双重的。首先，使用非参数方法将极端指标与欧洲累积降水量 (RR) 的趋势进行比较。其次，我们通过考虑欧洲不同地区与大规模过程的关系，使用不同的遥相关模式来分析在欧洲不同地区发现的地理上相反的趋势。该研究是使用 EU ENSEMBLES 项目中开发的网格 E-OBS 数据集完成的四个季节。在冬季和夏季，CWD 和 CDD 存在不同的变异模式，分别具有南北和东西向配置。我们考虑物理因素，以便通过将大规模过程和极端降水联系起来来了解极端事件的变化。冬季和夏季与北大西洋涛动的相反关联，以及与斯堪的纳维亚和东大西洋模式以及春季和秋季厄尔尼诺/南方涛动事件的关系，使我们能够深入了解趋势差异。全年大西洋数十年涛动与 R95pTOT 之间存在显着关系。利用大气变量和海面温度通过合成图分析了最大的极端异常。这项工作中发现的极端降水指数和大尺度变量的关联可能为降尺度技术中极值预测的新可能性铺平道路。
A growing interest in extreme precipitation has spread through the scientific community due to the effects of global climate change on the hydrological cycle, and their threat to natural systems' higher than average climatic values. Understanding the variability of precipitation indices and their association to atmospheric processes could help to project the frequency and severity of extremes. This paper evaluates the trend of three precipitation extremes: the number of consecutive dry/wet days (CDD/CWD) and the quotient of the precipitation in days where daily precipitation exceeds the 95th percentile of the reference period and the total amount of precipitation (or contribution of very wet days, R95pTOT). The aim of this study is twofold. First, extreme indicators are compared against accumulated precipitation (RR) over Europe in terms of trends using non-parametric approaches. Second, we analyse the geographically opposite trends found over different parts of Europe by considering their relationships with large-scale processes, using different teleconnection patterns. The study is accomplished for the four seasons using the gridded E-OBS data set developed within the EU ENSEMBLES project. Different patterns of variability were found for CWD and CDD in winter and summer, with north-south and east-west configurations, respectively. We consider physical factors in order to understand the extremes' variability by linking large-scale processes and precipitation extremes. Opposite associations with the North Atlantic Oscillation in winter and summer, and the relationships with the Scandinavian and East Atlantic patterns as well as El Nino/Southern Oscillation events in spring and autumn gave insight into the trend differences. Significant relationships were found between the Atlantic Multidecadal Oscillation and R95pTOT during the whole year. The largest extreme anomalies were analysed by composite maps using atmospheric variables and sea surface temperature. The association of extreme precipitation indices and large-scale variables found in this work could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.