RaInDROP Tool

In a warming climate, more intense, frequent, and/or longer-duration extreme precipitation events are expected, which can create conditions that favor more intense and frequent flooding. Evaporation rates increase with warmer temperatures which makes for a wetter atmosphere, one that is primed for intense and heavy precipitation.

The current practice within the US is to use NOAA Atlas 14 IDF precipitation values for set duration (e.g., 24-hour) and return period (e.g., 50-year storm). Since we are a few years out from the delivery of Atlas 15 (future precipitation curves) from NOAA, NCDOT and NCORR funded the State Climate Office of North Carolina to create a dataset showing how Atlas 14 values may change in a warming climate.

We used a downscaled climate change dataset to scale NOAA Atlas 14 within NC. We considered changes at mid-century/end-century for two different greenhouse gas emission scenarios (RCP4.5 – a middle of the road scenario and RCP8.5 – a high scenario). We created IDF curves to quantify changes in regional precipitation extremes across North Carolina.

Scale factors (future/historical) are derived using the Localized Constructed Analogs (LOCA): downscaled climate change projections (~6km horizontal resolution). The LOCA downscaled data supported the 4th and 5th National Climate Assessments.

These scale factors were used to scale NOAA Atlas 14 at individual grid points to create a usable point frequency estimate tool – Future IDF Curve Tool. This RaInDROP Tool or the RAinfall INtensity, Duration and Return for Observations and Projections Tool for North Carolina, makes for easy access to these data. The tool is still in beta form/development.