Detection and attribution of trends in individual at-site series of hydrological extremes is routinely undertaken using simple linear regression-based models. However, the available records are often too short to allow a consistent assessment of trends across different stations in a region. The theoretical developments presented in this paper propose a new method for estimating a regional regression slope parameter across a region, or pooling group, of catchment considered hydrologically similar, and where annual maximum events at different sites are cross-correlated. Assuming annual maximum events to follow a two-parameter log-normal distribution, a series of Monte Carlo simulations demonstrate the ability of the new framework to accurately identify the regional slope, and provide estimates with a reduced sampling variability as compared to the equivalent at-site estimates, thereby enhancing the statistical power of the trend test. This regionally-based trend estimates would allow for a clear characterization of changes across several stations in a region. Finally, the new method is applied to national dataset of annual maximum series of peak flow from 662 gauging sites located across the United Kingdom. The results show that the regional slope estimates are significantly positive (p < 0.05) consistently in the west and north of the country, while mostly not significant in the east and south. This translate into a corresponding increase in design flood (as measured by regional magnification factors) of up-to 50% for time horizon of 50-years into the future.

通常使用简单的基于线性回归的模型来进行单个现场水文极端事件趋势的检测和归因。但是，可用的记录通常太短，无法对区域中不同站点的趋势进行一致的评估。本文提出的理论发展提出了一种新方法，用于估算被认为在水文上相似，且不同地点的年度最大事件相互关联的流域的区域或汇聚组的区域回归斜率参数。假设年度最大事件遵循两参数对数正态分布，一系列的蒙特卡洛模拟证明了新框架能够准确识别区域坡度，与等效的现场估算相比，估算值的抽样变异性降低了，从而增强了趋势测试的统计能力。这种基于区域的趋势估计将可以清楚地表征一个区域中多个站点的变化。最后，该新方法被应用于来自全英国662个测量站的年度最大峰值流量年序列国家数据集。结果表明，区域坡度估计值明显为正（将该新方法应用于来自英国各地662个测量站点的年度最大峰值流量的国家数据集。结果表明，区域坡度估计值明显为正（将该新方法应用于来自英国各地662个测量站点的年度最大峰值流量的国家数据集。结果表明，区域坡度估计值明显为正（p  <0.05）在该国的西部和北部始终如一，而在东部和南部则不显着。这意味着在未来50年的时间范围内，设计洪水（以区域放大系数衡量）相应增加高达50％。