School of Civil and Environmental Engineering, University of New South Wales, Sydney, 2052, Australia.
Sci Rep. 2017 Aug 11;7(1):7945. doi: 10.1038/s41598-017-08481-1.
There is overwhelming consensus that the intensity of heavy precipitation events is increasing in a warming world. It is generally expected such increases will translate to a corresponding increase in flooding. Here, using global data sets for non-urban catchments, we investigate the sensitivity of extreme daily precipitation and streamflow to changes in daily temperature. We find little evidence to suggest that increases in heavy rainfall events at higher temperatures result in similar increases in streamflow, with most regions throughout the world showing decreased streamflow with higher temperatures. To understand why this is the case, we assess the impact of the size of the catchment and the rarity of the event. As the precipitation event becomes more extreme and the catchment size becomes smaller, characteristics such as the initial moisture in the catchment become less relevant, leading to a more consistent response of precipitation and streamflow extremes to temperature increase. Our results indicate that only in the most extreme cases, for smaller catchments, do increases in precipitation at higher temperatures correspond to increases in streamflow.
在变暖的世界中，强降水事件的强度正在增加，这一点已达成压倒性共识。人们普遍预计，这种增加将相应地转化为洪水的增加。在这里，我们使用非城市流域的全球数据集，研究了极端日降水量和径流量对日温度变化的敏感性。我们几乎没有证据表明，在较高温度下，强降雨事件的增加会导致径流量的相似增加，世界上大多数地区的径流量随着温度的升高而减少。为了理解为什么会这样，我们评估了流域大小和事件稀有性的影响。随着降水事件变得更加极端，流域面积变得更小，像流域初始湿度这样的特征变得不那么重要，导致降水和径流量极值对温度升高的响应更加一致。我们的结果表明，只有在最极端的情况下，对于较小的流域，较高温度下的降水增加才对应于径流量的增加。
