Your search found 14 records
(Location: IWMI-HQ Call no: PER Record No: H013092)
The validity of some of the simplifying assumptions in a conceptual water balance model is investigated by comparing simulation results from the conceptual model with simulation results from a three-dimensional physically based numerical model and with field observations. We examine, in particular, assumptions and simplifications related to water table dynamics, vertical soil moisture and pressure head distribution, and subsurface flow contributions to stream discharge. The conceptual model relies on a topographic index to predict saturation excess runoff and on Philip's infiltration equation to predict infiltration excess runoff. The numerical model solves the three-dimensional Richards equation describing flow in variably saturated porus media, and handles seepage face boundaries, infiltration excess and saturation excess runoff production, and soil driven and atmosphere driven surface fluxes. The study catchments are located in the North Appalachian ridge and valley region of eastern Pennsylvania. Hydrologic data collected during the MACHYDRO 90 field experiment are used to calibrate the models and to evaluate simulation results. It is found that water table dynamics as predicted by the conceptual model are close to the observations in a shallow water well and therefore, that a linear relationship between a topographic index and the local water table depth is found to be a reasonable assumption for catchment scale modeling. However, the hydraulic equilibrium assumption is not valid for the upper 100 cm layer of the unsaturated zone and a conceptual model that incorporates a root zone is suggested. Furthermore, theoretical subsurface flow characteristics from the conceptual model are found to be different from field observations, numerical simulation results, and theoretical baseflow recession characteristics based on Boussinesq's groundwater equation.
2 Wood, E. F.. 1994. Scaling, soil moisture and evapotranspiration in runoff models. Advances in Water Resources, 17(1-2):25-34.
(Location: IWMI-HQ Call no: PER Record No: H015114)
(Location: IWMI-HQ Call no: PER Record No: H015979)
4 O'Neill, P. E.; Hsu, A. Y.; Jackson, T. J.; Wood, E. F.; Zion, M. 1997. The impact of microwave-derived surface soil moisture on watershed hydrological modeling. In Kite, G. W.; Pietroniro, A.; Pultz, T. J. (Eds.), Applications of remote sensing in hydrology: Proceedings of the Third International Workshop, 16-18 October 1996, NASA, Goddard Space Flight Center, Greenbelt, Maryland, USA. Saskatchewan, Canada: National Hydrology Research Institute. pp.211-226.
(Location: IWMI-HQ Call no: 621.3678 G000 KIT Record No: H020555)
5 Dubayah, R. O.; Wood, E. F.; Engman, E. T.; Czajkowski, K. P.; Zion, M.; Rhoads, J. 2000. Remote sensing in hydrological modeling. In Schultz, G. A.; Engman, E. T. (Eds.), Remote sensing in hydrology and water management. Berlin, Germany: Springer. pp.85-110.
(Location: IWMI-HQ Call no: 621.3678 G000 SCH Record No: H027011)
(Location: IWMI-HQ Call no: P 5543 Record No: H027324)
7 Peters-Lidard, C. D.; Pan, F.; Wood, E. F.. 2001. A re-examination of modeled and measured soil moisture Spatial variability and its implications for land surface modeling. Advances in Water Resources, 24(9-10):1069-1083.
(Location: IWMI-HQ Call no: PER Record No: H029562)
8 Crow, W. T.; Wood, E. F.. 2003. The assimilation of remotely sensed soil brightness temperature imagery into a land surface model using ensemble Kalman filtering: A case study based on ESTAR measurements during SGP97. Advances in Water Resources, 26(2):137-149.
(Location: IWMI-HQ Record No: H031176)
(Location: IWMI-HQ Call no: P 6746 Record No: H033861)
10 Wood, E. F.. 1995. Scaling behaviour of hydrological fluxes and variables: Empirical studies using a hydrological model and remote sensing data. Hydrological Processes, 9:331-346.
(Location: IWMI-HQ Call no: P 6757 Record No: H034182)
11 Wood, E. F.; Roundy, J. K.; Troy, T. J.; van Beek, L. P. H.; Bierkens, M. F. P.; Blyth, E.; de Roo, A.; Doll, P.; Ek, M.; Famiglietti, J.; Gochis, D.; van de Giesen, N.; Houser, P.; Jaffe, P. R.; Kollet, S.; Lehner, B.; Lettenmaier, D. P.; Peters-Lidard, C.; Sivapalan, M.; Sheffield, J.; Wade, A.; Whitehead, P. 2011. Hyperresolution global land surface modeling: meeting a grand challenge for monitoring earth’s terrestrial water. Water Resources Research, 47:10.
(Location: IWMI HQ Call no: e-copy only Record No: H045083)
(1.23 MB)
(Location: IWMI HQ Call no: 363.34929 G000 SHE Record No: H046319)
(0.46 MB)
(Location: IWMI HQ Call no: e-copy only Record No: H048083)
(4.00 MB) (4.00 MB)
Recent droughts and heatwaves showed the vulnerability of the electricity sector to surface water constraints with reduced potentials for thermoelectric power and hydropower generation in different regions. Here we use a global hydrological-electricity modelling framework to quantify the impacts of recent drought and warm years on hydropower and thermoelectric power usable capacity worldwide. Our coupled modelling framework consists of a hydrological model, stream temperature model, hydropower and thermoelectric power models, and was applied with data of a large selection of hydropower and thermoelectric power plants worldwide. Our results show that hydropower utilisation rates were on average reduced by 5.2% and thermoelectric power by 3.8% during the drought years compared to the long-term average for 1981–2010. Statistically significant (p < 0.01) impacts on both hydropower and thermoelectric power usable capacity were found during major drought years, e.g. 2003 in Europe (-6.6% in hydropower and -4.7% in thermoelectric power) and 2007 in Eastern North America (-6.1% in hydropower and -9.0% in thermoelectric power). Our hydrological-electricity modelling framework has potential for studying the linkages between water and electricity supply under climate variability and change, contributing to the quantification of the 'water-energy nexus'.
14 Fisher, J. B.; Melton, F.; Middleton, E.; Hain, C.; Anderson, M.; Allen, R.; McCabe, M. F.; Hook, S.; Baldocchi, D.; Townsend, P. A.; Kilic, A.; Tu, K.; Miralles, D. D.; Perret, J.; Lagouarde, J.-P.; Waliser, D.; Purdy, A. J.; French, A.; Schimel, D.; Famiglietti, J. S.; Stephens, G.; Wood, E. F.. 2017. The future of evapotranspiration: global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources. Water Resources Research, 53(4):2618-2626. [doi: https://doi.org/10.1002/2016WR020175]
(Location: IWMI HQ Call no: e-copy only Record No: H048201)
(1.18 MB) (1.18 MB)
The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, and highlight both the outstanding science and applications questions and the actions, especially from a space-based perspective, necessary to advance them.
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