Abstract
Weather radar systems provide detailed information on spatial rainfall patterns known to play a significant role in runoff generation processes. In the current study, we present an innovative approach to exploit spatial rainfall information of air mass thunderstorms and link it with a watershed hydrological model. Observed radar data are decomposed into sets of rain cells conceptualized as circular Gaussian elements and the associated rain cell parameters, namely, location, maximal intensity and decay factor, are input into a hydrological model. Rain cells were retrieved from radar data for several thunderstorms over southern Arizona. Spatial characteristics of the resulting rain fields were evaluated using data from a dense rain gauge network. For an extreme case study in a semi-arid watershed, rain cells were derived and fed as input into a hydrological model to compute runoff response. A major factor in this event was found to be a single intense rain cell (out of the five cells decomposed from the storm). The path of this cell near watershed tributaries and toward the outlet enhanced generation of high flow. Furthermore, sensitivity analysis to cell characteristics indicated that peak discharge could be a factor of two higher if the cell was initiated just a few kilometers aside.
Original language | English |
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Pages (from-to) | 843-860 |
Number of pages | 18 |
Journal | Advances in Water Resources |
Volume | 29 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2006 |
Bibliographical note
Funding Information:This research was funded by grants from the International Arid Lands Consortium (IALC, 00R-11) and the Vaadia-BARD Postdoctoral Award No. FI-303-2000 from BARD, The United States–Israel Binational Agricultural Research and Development Fund. The research is based upon work supported in part by SAHRA (Sustainability of semi-Arid Hydrology and Riparian Areas) under the STC Program of the National Science Foundation, Agreement No. EAR-9876800 and by grants from the Hydrologic Laboratory of the National Weather Service, Grants NA87WHO582 and NA07WH0144. We are thankful to the staff members of the Southwest Watershed Research Center, USDA-ARS, for their assistance and diligent collection of high quality, long-term, watershed data. We thank Jonathan J. Gourley, of the University of Oklahoma, for his help in obtaining the radar data for the Phoenix area and to the staff of the Flood Control District of Maricopa County in providing gauge data for the same area. We also thank the editor and three anonymous reviewers for their beneficial comments that helped to improve this paper.
Keywords
- Distributed hydrological models
- Rain cell
- Rainfall
- Spatial patterns
- Thunderstorms
- Weather radar