Climate change effects on sub-daily precipitation in Spain

ABSTRACT Sub-daily extreme precipitation events are responsible for flash floods which generate impacts that cannot be analysed using daily precipitation information. In this study, we assess the effects of climate change in sub-daily rainfall statistics for Spain. We downscale daily records to the hourly scale using machine learning techniques, and then update the downscaling predictors to generate the sub-daily rainfall projections. We use the atmospheric climate change projections of the Coordinated Regional Climate Downscaling Experiment (CORDEX) initiative to update the downscaling predictors. We do not observe important differences between climate change scenarios, except in the average amounts of precipitation. Climate change will intensify the most extreme sub-daily events overall, as well as increase the number of dry spells, although some dry climates concentrate most of the effects. The intensification will increase the 100-year return period event, especially in those regions where large variances are observed, making flash floods more intense in the future.