Projected changes in extreme precipitation at sub-daily and daily time scales

Significant progress has been made in relation to extreme precipitation and climate change. Overall, the tendency for dry areas to get drier and wet areas to get wetter has been identified. However, much of the work has focused on the daily time scale, and much less is known about sub-daily precipitation, despite indications that climate change could have more of an impact on sub-daily (e.g., 3-hourly) rather than daily precipitation. To complicate the matter, there is still a need to evaluate the performance of global climate models in reproducing the precipitation statistics at the sub-daily time scales. Therefore, the goal of this study is to explore the projected changes in sub-daily precipitation compared to the daily scale, and understand model accuracy at these finer time scales. We found that model accuracy is low for sub-daily precipitation for most of the models and model performance increases as the temporal resolution becomes coarser. In addition, remarkable differences exist in the accuracy of different GCMs in simulating sub-daily precipitation. However, there are several models that stand out comparatively for both time scales. Ultimately, the greatest changes in extreme precipitation, both increases and decreases, are generally in the tropics. There is a clear connection between greenhouse gas concentrations and extreme precipitation, with the greatest changes occurring towards the end of the 21st century when greenhouse gas concentrations are the greatest. At both time scales, models generally show a large increase in precipitation in the tropics, and global averages indicate increases in extreme precipitation will be more dominant than decreases. Changes are projected to be stronger at the sub-daily than daily scale, especially between 30 degrees N and 30 degrees S.