The flooding in South Yorkshire in the United Kingdom (UK) in autumn 2019 saw one fatality, at least 500 properties flooded and 1 200 households evacuated. The worst of the flooding occurred after very high 24-h rainfall totals of up to 82 mm fell on already saturated ground. This followed very high 24-h rainfall totals in the region just two weeks earlier of up to just under 50 mm. In the light of anthropogenic climate change, it is expected that extreme rainfall events are set to become more intense as a result of increased global mean temperatures and the Clausius-Clapeyron relation. Here we investigate the change in risk of such extreme rainfall events in the UK in autumn using a new index R_{50mm_OND}, representing the mean number of daily precipitation totals in excess of 50 mm in October–December each year. Using high resolution regional model datasets and observations we show that extreme rainfall totals for the UK are increasing exponentially as a result of anthropogenic climate change. Observations show that the frequency of extreme daily precipitation in the form of R_{50mm_OND} has already increased by 60% (95% CI: 44–76) in the UK between the beginning of the 20th and 21st centuries. R_{50mm_OND} is projected to increase even further between 2019 and 2080, by 85% (95% CI: 73–97) according to a Representative Concentration Pathway (RCP) 8.5 scenario of anthropogenic emissions. While higher resolution models (12 km spatial resolution) were able to capture the observed changes, lower resolution models were not. This underlines the importance of high-resolution models for modelling extreme precipitation seen in late autumn and early winter, not just for convective rainfall in the summer. A more specific analysis of the November 2019 event looked at the mean of the two highest daily precipitation totals in October–November in the South Yorkshire region. This found a long-term shift to higher daily rainfall totals for this mean with an increase in intensity of the top 10% of events, suggesting that the South Yorkshire region in autumn is more at risk of flooding in the future without effective adaptation measures.

2019 年秋季，英国 (UK) 南约克郡的洪水造成 1 人死亡，至少 500 处房屋被淹，1200 户家庭撤离。最严重的洪水发生在已经饱和的地面上，24 小时的降雨总量高达 82 毫米。在此之前，该地区 24 小时的降雨总量非常高，仅在两周前就达到了 50 毫米以下。鉴于人为气候变化，由于全球平均气温升高和克劳修斯-克拉珀龙关系，预计极端降雨事件将变得更加强烈。在这里，我们使用新指数 R _{50mm_OND}调查了英国秋季此类极端降雨事件的风险变化，代表每年 10 月至 12 月日降水总量超过 50 毫米的平均数。我们使用高分辨率区域模型数据集和观测结果表明，由于人为气候变化，英国的极端降雨总量呈指数增长。观测表明，在20 世纪初到 21 世纪初，英国以 R _{50mm_OND}形式出现的极端日降水频率已经增加了 60%（95% CI：44-76）。R _{50mm_OND}根据人为排放的代表性浓度路径 (RCP) 8.5 情景，预计在 2019 年至 2080 年之间将进一步增加 85%（95% CI：73-97）。虽然较高分辨率的模型（12 公里空间分辨率）能够捕捉到观察到的变化，但较低分辨率的模型则不然。这强调了高分辨率模型对于模拟深秋和初冬极端降水的重要性，而不仅仅是夏季的对流降雨。对 2019 年 11 月事件的更具体分析着眼于南约克郡地区 10 月至 11 月两个最高日降水总量的平均值。结果发现，随着前 10% 事件的强度增加，该平均值会长期转向更高的日降雨量总量，