Sensitivity of Intensity–Duration–Frequency Curves to the Temporal Resolution of Rainfall Observations

In this study, we leveraged a gap-free data set of rainfall across Florida observed at 15-min intervals at 30 weather stations over a period of 16 years to examine the impact of temporal aggregation (or temporal resolution) of rainfall observations on intensity–duration–frequency (IDF) curves. This application is one of the first using an extensive network of subhourly observed rainfall data for the derivation of rainfall IDF curves over Florida. Using less frequent rainfall measurements led to a systematic reduction in the area under the IDF curve (AUC), suggesting an underestimation of the intensity of rainfall across all 30 stations, with the largest reduction at the largest aggregation period and smallest return period. Our analysis reveals that the loss of information of rainfall intensity in Florida with aggregation interval follows a logarithmic fit, with significant losses occurring in the first three hours. Our study concludes that rainfall observations with subhourly measurements are critical to estimate IDF curves over Florida.