David M. Brommer Department of Geography University of Alabama
description
Transcript of David M. Brommer Department of Geography University of Alabama
Spatial Characterization of Storm Internal Precipitation
Distribution for the Southeastern United States
(1980-2009)
David M. BrommerDepartment of Geography
University of Alabama
Introduction Quantifying the character of
precipitation• Precipitation amount• Precipitation timing• Precipitation intensity• Precipitation modeling
Why?• Capture the variability in precipitation to
plan, design, and manage water resources
Data and Methods Hourly Precipitation Dataset 3240
• National Climatic Data Center 6,500 primary, secondary and cooperative
weather stations from 1900 to present Reduced to 143 stations
• Primary (first-order) stations • Precipitation measured to 0.254 mm hr-1 (0.01 inch)• No data gaps from 1980 – 2009
Precipitation events last at least three hours (no events of one- or two-hour duration included)
Data and Methods Why three-hour or longer events?
• Statistical tests required a minimum of three data points
• Air mass (pulse)-type thunderstorms removed• Assess the variability within longer-duration
precipitation occurrences 149,197 individual, three-hour or longer
events identified To assess internal variability, skewness
and kurtosis are used
* Precipitation events three hours or longer
Precipitation Skewness
Precipitation Kurtosis
Average number of maxima (peaks) within the precipitation disribution
Conclusion Internal character of precipitation
across the U.S. highly variable • Especially the Southeast• Seasonal variability, too
Convective events, initially, play a roll in determining internal distribution
Future work?• Seasonal signal (cold-season, in paticular)• Incorporate additional stations
15-minute data?