An assessment of changes in seasonal and annual extreme rainfall in the UK between 1961 and 2009
An assessment of changes in seasonal and annual extreme rainfall in the UK between 1961 and 2009
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DOI：
10.1002/joc.3503
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发表时间：
2013-04-01
期刊：
影响因子：
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通讯作者：
Blenkinsop, Stephen
中科院分区：
文献类型：
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作者：
Jones, Mari R.;Fowler, Hayley J.;Blenkinsop, Stephen
越来越多的证据支持政府间气候变化专门委员会的论点，即人为气候变化可能导致水文极端变化。水资源管理者也越来越担心这些变化的性质，以及我们如何调整自己的行为以适应这些变化。特别是，极端的多日降雨事件是近年来严重洪灾事件的一个重要因素。在这里，我们提供了一项关于英国极端降雨的最新研究，重点是1961-2009年期间的季节和年度最大降雨量的变化。我们使用区域频率分析来检验从广义极值分布曲线获得的估计回收期的大小的变化。重现期估计使用完整记录和10年间隔进行分析，以确定极端降雨量分布中自然变异性和长期变化的相对重要性。估计重现期的变化幅度在空间上是不同的，在英国北部和西部，主要是周期性强迫，如北大西洋涛动(NAO)，叠加在正常的季节性波动上。相反，季节性对南部和东部的震级影响最大。我们确认，以前报告的春季和秋季极端降雨事件的增加仍在继续。同样，持续时间较长的冬季活动的强度继续增加，在苏格兰和英格兰西南部有记录的整整50年中，重现期估计从25年减少到大约5年一次。相比之下，持续时间较短的夏季降雨事件强度继续下降，而持续时间较长的事件强度似乎有所增加。这些结果可能会对防洪设计和规划以及可能对极端降雨敏感的农业实践产生重大影响。版权所有(C)2012年英国皇家气象学会
There is a growing body of evidence supporting the Intergovernmental Panel on Climate Change's contestation that changes to hydrological extremes as a result of anthropogenic climate change are likely. There is also a growing level of concern among water resource managers about the nature of these changes and how we might adapt our behaviour to accommodate them. In particular, extreme multi-day rainfall events have been a significant contributing factor to the severe flood events of recent years. Here we provide an updated study of extreme rainfall in the UK, focussing on changes to seasonal and annual maxima over the period 1961-2009. We employ regional frequency analysis to examine changes in the magnitude of estimated return periods obtained from generalized extreme value distribution curves. Return period estimates are analysed using both the full record and using 10 year intervals to determine the relative importance of natural variability and long-term changes in extreme rainfall distribution. The magnitude of changes in estimated return periods are spatially varied, and dominated in northern and western parts of the UK by a periodic forcing such as the North Atlantic Oscillation (NAO), superimposed on normal seasonal fluctuations. In contrast, seasonality has the greatest influence on event magnitude in the south and east. We confirm that previously reported increases in spring and autumn extreme rainfall events have continued. Similarly, longer duration winter events have continued to increase in intensity, with a decrease in return period estimate from a 25-year to around a 5-year event over the full 50 years of record in parts of Scotland and Southwest England. In contrast, short-duration summer rainfall events have continued to decline in intensity, whereas longer duration events appear to be increasing in intensity. These results may have significant implications for flood defence design and planning, as well as to agricultural practices which may be sensitive to extreme rainfall. Copyright (c) 2012 Royal Meteorological Society