Temporal scaling properties of extreme rainfall and intensity-duration-frequency curves in the UK

Rainfall estimation in ungauged areas is becoming one of the research hotspots recently. From a case study in the UK, this study builds a sub-daily rainfall estimation model based on more widely available daily series data from 151 gauges. In this study, we stratify the scaling properties of UK rainfall into homogenous rainfall zones, geophysical factors, seasons, and air masses to investigate how these scaling properties change temporally and spatially. We use temporal scaling techniques to extract the scaling relationship between sub-daily rainfall intensity and annual maximum series along with all possible factors introduced above. The estimated rainfall is validated with observed rainfall data and shows a higher degree of agreement. Finally, we compare the IDF (Intensity-Duration-Frequency) curves for both estimated and observed data. Such scaling relationships can support scientists and governments to estimate extreme rainfall at a specific duration and return period in ungauged regions. This method can also generate design rainfall time series for flood simulation models to evaluate present and future pluvial flood risks in urban areas.