In cooperation with the Texas Department of Transportation
Atlas of Interoccurrence Intervals for Selected Thresholds of Daily Precipitation in Texas
By William H. Asquith and Meghan C. Roussel
U.S. Geological Survey
Water-Resources Investigations Report 03–4281
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CONTENTS
Abstract
Introduction
Data Sources
Previous Studies
Approach
Site-Specific Interoccurrence Intervals
Regionalization of Interoccurrence Intervals
Interoccurrence Intervals for Selected Daily Precipitation Thresholds in Texas
Statewide Interoccurrence Interval Maps
Influence of Elevation on Interoccurrence Intervals West of the Pecos River
Intra-Annual Variations in Interoccurrence Intervals
Example Applications
Site-Specific Median 6-Month Daily Precipitation Threshold
Site-Specific Median Number of Occurrences
Intra-Annual Variations in Interoccurrence Intervals
Regional Estimation of Mean Interoccurrence Interval
Summary
Selected References
Figures
| 1. |
Map showing locations of 1,306 National Weather Service daily precipitation stations in Texas | |
| 2. |
Example of abbreviated time series of daily precipitation for station 428 Austin Camp Mabry | |
| 3. |
Example interoccurrence interval computations for a hypothetical data set | |
4–13. |
Maps showing interoccurrence interval for a: | |
| 4. |
0.05-inch and greater daily precipitation threshold for Texas | |
| 5. |
0.10-inch and greater daily precipitation threshold for Texas | |
| 6. |
0.25-inch and greater daily precipitation threshold for Texas | |
| 7. |
0.50-inch and greater daily precipitation threshold for Texas | |
| 8. |
0.75-inch and greater daily precipitation threshold for Texas | |
| 9. |
1.0-inch and greater daily precipitation threshold for Texas | |
| 10. |
1.5-inch and greater daily precipitation threshold for Texas | |
| 11. |
2.0-inch and greater daily precipitation threshold for Texas | |
| 12. |
2.5-inch and greater daily precipitation threshold for Texas | |
| 13. |
3.0-inch and greater daily precipitation threshold for Texas | |
14a–j. |
Graphs showing relation between interoccurrence
interval and elevation west of the Pecos River, west Texas |
|
15–24. |
Boxplots showing distribution of ratio of interoccurrence interval for month to mean interoccurrence interval for period of record at station for a: | |
| 15. |
0.05-inch and greater daily precipitation threshold for Texas | |
| 16. |
0.10-inch and greater daily precipitation threshold for Texas | |
| 17. |
0.25-inch and greater daily precipitation threshold for Texas | |
| 18. |
0.50-inch and greater daily precipitation threshold for Texas | |
| 19. |
0.75-inch and greater daily precipitation threshold for Texas | |
| 20. |
1.0-inch and greater daily precipitation threshold for Texas | |
21. |
1.5-inch and greater daily precipitation threshold for Texas | |
22. |
2.0-inch and greater daily precipitation threshold for Texa | |
23. |
2.5-inch and greater daily precipitation threshold for Texas | |
24. |
3.0-inch and greater daily precipitation threshold for Texas | |
25–28. |
Graphs showing: | |
25. |
Relation between adjusted mean and median interoccurrence ratios and month for 0.05- and 0.10-inch daily precipitation thresholds for Texas | |
26. |
Relation between adjusted mean interoccurrence ratio and month for 0.25-, 0.50-, 0.75-, 1.0-, 1.5-, 2.0-, 2.5-, and 3.0-inch daily precipitation thresholds for Texas | |
27. |
Relation between adjusted median interoccurrence ratio and month for 0.25-, 0.50-, 0.75-, 1.0-, 1.5-, 2.0-, 2.5-, and 3.0-inch daily precipitation thresholds for Texas | |
28. |
Relation between site-specific daily precipitation threshold and mean interoccurrence interval for station 428 Austin Camp Mabry and estimated median 6-month precipitation | |
Tables
| 1. |
Summary of National Weather Service daily precipitation stations in Texas with known names, latitudes, and longitudes |
| 2. |
National Weather Service daily precipitation stations in Texas, by county |
| 3. |
Summary of interoccurrence intervals for daily precipitation thresholds of 0.05 and 0.10 inch |
| 4. |
Summary of interoccurrence intervals for daily precipitation thresholds of 0.25 and 0.50 inch |
| 5. |
Summary of interoccurrence intervals for daily precipitation thresholds of 0.75 and 1.0 inch |
| 6. |
Summary of interoccurrence intervals for daily precipitation thresholds of 1.5 and 2.0 inches |
| 7. |
Summary of interoccurrence intervals for daily precipitation thresholds of 2.5 and 3.0 inches |
| 8. |
Example computation steps of interoccurrence intervals for a Poisson process described in text |
| 9. |
Summary of statewide interoccurrence interval statistics and diagnostic statistics of interoccurrence interval maps |
| 10. |
Summary of interoccurrence ratios by month for 0.05-inch and greater daily precipitation threshold |
| 11. |
Summary of interoccurrence ratios by month for 0.10-inch and greater daily precipitation threshold |
| 12. |
Summary of interoccurrence ratios by month for 0.25-inch and greater daily precipitation threshold |
| 13. |
Summary of interoccurrence ratios by month for 0.50-inch and greater daily precipitation threshold |
| 14. |
Summary of interoccurrence ratios by month for 0.75-inch and greater daily precipitation threshold |
| 15. |
Summary of interoccurrence ratios by month for 1.0-inch and greater daily precipitation threshold |
| 16. |
Summary of interoccurrence ratios by month for 1.5-inch and greater daily precipitation threshold |
| 17. |
Summary of interoccurrence ratios by month for 2.0-inch and greater daily precipitation threshold |
| 18. |
Summary of interoccurrence ratios by month for 2.5-inch and greater daily precipitation threshold |
| 19. |
Summary of interoccurrence ratios by month for 3.0-inch and greater daily precipitation threshold |
| 20. |
Regional estimates of mean interoccurrence interval of precipitation for Austin, Texas |
CONVERSION FACTORS AND VERTICAL DATUM
Multiply |
By |
To
obtain |
||
foot (ft) |
0.3048 |
meter (m) | ||
inch (in.) |
25.40 |
millimeter (mm) | ||
mile (mi) |
1.609 |
kilometer (km) |
Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29).
Abstract
A Poisson process model is used to define the distribution of interoccurrence intervals of daily precipitation in Texas. A precipitation interoccurrence interval is the time period between two successive rainfall events. Rainfall events are defined as daily precipitation equaling or exceeding a specified depth threshold. Ten precipitation thresholds are considered: 0.05, 0.10, 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, 2.5, and 3.0 inches. Site-specific mean interoccurrence interval and ancillary statistics are presented for each threshold and for each of 1,306 National Weather Service daily precipitation gages. Maps depicting the spatial variation across Texas of the mean interoccurrence interval for each threshold are presented. The percent change from the statewide standard deviation of the interoccurrence intervals to the root-mean-square error ranges from a magnitude minimum of (negative) -24 to a magnitude maximum of -60 percent for the 0.05- and 2.0-inch thresholds, respectively. Because of the substantial negative percent change, the maps are considered more reliable estimators of the mean interoccurrence interval for most locations in Texas than the statewide mean values.
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