Characterizing Spatio-Temporal Trends in Extreme Precipitation in Southeast Texas

• Activity Number: 73 - Modeling Spatial and Statio-Temporal Data
• Type: Contributed
• Date/Time: Monday, August 3, 2020 : 10:00 AM to 2:00 PM
• Sponsor: Section on Risk Analysis
• Author(s): Carly Fagnant* and Avantika Gori and Antonia Sebastian and Philip Bedient and Katherine Ensor
• Companies: Rice University - Statistics and Princeton University - Civil & Environmental Engineering and The University of North Carolina at Chapel Hill - Geological Sciences and Rice University - Civil & Environmental Engineering and Rice University
• Keywords: rainfall; extreme; precipitation; generalized Pareto; flooding; return level

Abstract

Rainfall extreme value analysis provides information that has been crucial in characterizing risk, designing successful infrastructure systems, and ultimately protecting people and property from the threat of rainfall-induced flooding. However, in the Houston region recent events (such as Hurricane Harvey) have highlighted the inability of existing analyses to accurately characterize current climate conditions. This study investigates spatio-temporal trends in extreme precipitation in southeast Texas using a statistical approach for peak-over-threshold modeling that employs a generalized Pareto distribution. Precipitation data from 601 rain gauges across the region are analyzed in 40-year moving time windows to evaluate shifts in extreme rainfall levels through time. Spatial analysis of these trends focuses on highlighting regions with increasing, stationary, and decreasing extreme rainfall. Return level estimates of extreme rainfall values are also compared to the current standards for Harris County. Results from this study identify areas that have experienced significant shifts in extreme rainfall, and can help inform where design standards may be inaccurate or outdated.