Citation:

Jalowska, A., T. Spero, D. Amatya, G. Gray, AND J. Bowden. Changes in the Future Extreme Precipitation Using Dynamically Downscaled Simulations From 2025 to 2100 for three forested and three urban stations in Southeastern U.S. Watersheds. Seventh Interagency Conference on Research in the Watersheds, Zoom, NC, November 16 - 19, 2020.

Impact/Purpose:

Presentation at the Seventh Interagency Conference on Research in the Watersheds. This year conference focus is Enhancing Landscapes for Sustainable Intensification and Watershed Resiliency. The conference offers a unique opportunity to engage with researchers from government, academic, non-profit, and community organizations working to protect, restore, and manage water resources at local to national scales.

Description:

The increasing trend in the frequency and intensity of extreme precipitation events and associate flooding has been well documented within the Southeastern U.S. using the historical climate records. Studies also describe dramatic ecosystem responses to extreme events with a plausible regime shifts in the intensity and quantity of runoff within some watersheds. Furthermore, climate models indicate that precipitation intensification will continue to increase throughout the twenty-first century. To address arising challenges related to changing precipitation characteristics, governing and managing bodies need information to prepare for future weather, which can be provided by the modelling community. Precipitation Intensity-Duration-Frequency (PIDF) curves are a common tool used to account for extreme precipitation events in urban and environmental planning. The PIDF curves estimate a frequency of occurrence of extreme rain events (rainfall amount within a given period of time) based on frequency analyses of the available data. This study presents analyses of the trends in extreme precipitation probabilities for 76 years (2025-2100) in three forested and three urban sites in the Southeastern U.S. The Weather Research and Forecasting (WRF) model was used to dynamically downscale two global climate models for the moderate and highest greenhouse gas emission scenario (RCP4.5 and RCP8.5) to 36-km. Downscaled global climate models used in the study (the Community Earth System Model (CESM) and the Geophysical Fluid Dynamics Laboratory coupled climate model (CM3)) indicate up to a 30% increase in the annual maximum precipitation by 2100, and an increased variability in the intensity and frequency of the extreme precipitation. The one-hundred-year recurrence interval precipitation amounts exhibit an increase up to 108% in the 1-h duration and up to 57% in 24-h duration return periods.

Record Details: