Impacts of Different Precipitation Data Sources on Water Budgets
Radar and rain-gauge precipitation datasets are used to explore the impacts of different precipitation data sources on water budget simulated by the VIC-3L (Three-layer Variable Infiltration Capacity) land surface model over the watershed of the Illinois River at Watts, which is at the border of Oklahoma and Arkansas. Hourly grid-based NEXRAD stage Ш precipitation data (approximately 4x4 km2) were aggregated in time and space to daily precipitation at 1/8th degree and compared with the University of Washington (UW) precipitation, which was gridded at 1/8th degree based on rain-gauge precipitation data. Comparison of precipitation indicates that the temporal cumulative NEXRAD precipitation generally underestimates precipitation compared to the UW and rain gauge measurements. Hyetograph obtained from the NEXRAD data in general appears to be narrower with higher peaks compared to the UW data; and the NEXRAD data has more superior capability to capture the precipitation spatial distribution than the UW data. Investigations of water fluxes based on simulations with the two kinds of precipitation data as forcing suggest that realistic streamflow compared to the observed daily streamflow at the outlet of the Illinois River at Watts can be obtained using both the NEXRAD and UW precipitation after model calibration. Compared to soil moisture of the total zone, runoff and evapotranspiration are more sensitive to temporal and spatial distributions of precipitation, with runoff being the most sensitive. Also, runoff and evapotranspiration obtained based on the NEXRAD precipitation show more heterogeneity spatially than the simulation based on the UW precipitation. In addition, the magnitudes of the components of the water budget can be strongly impacted by the VIC-3L calibrated parameters, but their spatial distribution patterns may not be significantly affected.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 860033
- Report Number(s):
- PNNL-SA-41322; JHYDA7; KP1205030; TRN: US200523%%175
- Journal Information:
- Journal of Hydrology, 298(1-4):311-334, Vol. 298, Issue 1-4; ISSN 0022-1694
- Country of Publication:
- United States
- Language:
- English
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