Quantifying Effective Precipitation and Its Non-Stationarity to Improve Drought Assessments in the Southeastern United States
This project will improve how drought is monitored in the Southeastern U.S. by developing a new drought indicator based on the amount of water that actually soaks into the ground after rainfall.
When large rain events dump several inches of water, much of it runs off, and within a week or two, we’re right back where we started. For this project, “Effective precipitation” refers to the portion of rainfall that actually infiltrates the soil to replenish soil moisture and water resources. Climate models indicate that the Southeast will continue to experience greater variation in rainfall intensity, so accounting for “effective precipitation” is important to accurately monitor drought.
The team will develop a new “effective precipitation” tool to better capture drought conditions that are often missed by traditional drought monitoring methods. The research team will work with state and regional partners to ensure the tool is accurate, timely, and useful. They and partners will share results through existing climate portals used by farmers, emergency managers, and government officials. These improvements will help communities better prepare for and respond to drought.
This research is part of the Fiscal Year 2026 NIDIS Coping with Drought research competition. For more information, please contact Britt Parker (britt.parker@noaa.gov).
Research Snapshot
Lee Ellenburg, University of Alabama Huntsville
Rob Junod, University of Alabama in Huntsville; Pam Knox, Georgia Weather Network, University of Georgia; William Lusher, Florida Automated Weather Network, University of Florida; John Nielsen-Gammon, Texas State Climate Office, Southern Regional Climate Center, Texas A&M University
What to expect from this research
- This project will improve drought forecasting, enhance water resource management, and increase climate resilience across the Southeast U.S., particularly for those most vulnerable to drought impacts.
- The research team will develop a modified Standardized Precipitation Index (SPI) index that incorporates effective precipitation—SPIe—and compare this to traditional drought indices that do not account for effective precipitation. The resulting operational product will provide near-real-time drought assessments, which platforms like the Southern Regional Climate Center’s Integrated Water Portal and Drought.gov will host.
- The team will also form a Southeastern regional working group, consisting of state climate offices, regional stakeholders, and drought monitoring experts. This working group will provide critical feedback throughout the project’s development, ensuring that the tools are relevant, practical, and integrated into existing drought monitoring systems such as the Southeastern Drought Early Warning System.
