HR: 1340h
AN: H33B-1262    [Abstracts]
TI: Trends in Pan Evaporation and Application of the Complimentary Relationship of Evaporation in the Great Basin, USA
AU: * Huntington, J L
EM: justinh@dri.edu
AF: University of Nevada Reno, Hydrologic Sciences Program, 1664 N. Virginia St., Reno, NV 89557, United States
AU: Caldwell, T
EM: Todd.Caldwell@dri.edu
AF: Desert Research Institute, Division of Earth and Ecosystem Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Naranjo, R
EM: naranjor@unr.nevada.edu
AF: University of Nevada Reno, Hydrologic Sciences Program, 1664 N. Virginia St., Reno, NV 89557, United States
AU: Burak, S
EM: sburak@lanset.com
AF: University of Nevada Reno, Hydrologic Sciences Program, 1664 N. Virginia St., Reno, NV 89557, United States
AU: Tyler, S
EM: tylers@unr.edu
AF: University of Nevada Reno, Department of Geological Sciences and Engineering, 1664 N. Virginia St., Reno, NV 89557, United States
AB: Evaluating available water resources in the Great Basin is an increasing topic of discussion by several local, State, and Federal government agencies due to proposals for water importation into areas of rapid population growth. In estimating a water budget for a particular flow system in the Great Basin, groundwater evapotranspiration (ET) from phreatophyte vegetation is often the most important as it is the only water budget component that can be estimated with some certainty, opposed to mountain block recharge and interbasin subsurface flow. Bouchet's complimentary relationship of evaporation has drawn noteworthy attention in recent years, not only because of its use in explaining observed changes in the hydrologic cycle, but also for its use in predicting ET using readily available meteorological data. The objective of this presentation is twofold: 1) to discuss pan evaporation trends in the Great Basin, and 2) discuss results from the application of the complimentary relationship for predicting evapotranspiration from phreatophyte shrubs when compared to measured ET at several U.S. Geological Survey eddy correlation and Bowen ratio sites. Initial findings indicate a decrease of pan evaporation in Death Valley, CA, the lowest, hottest, and driest location in North America, an opposite trend from analysis of several other sites in the Great Basin that indicate an increase of pan evaporation. It is believed that these opposing trends are likely the result of local water availability surrounding the pan, and or data quality. The application of a symmetric complimentary relationship indicate satisfactory results when compared to measured evapotranspiration, however, during the hottest months of the year the predicted ET over estimates the measured. Further investigation of micrometeorological data suggests that an asymmetric complimentary relationship between potential and actual ET exists, and when taken into account, improves the predictions markedly.
DE: 1833 Hydroclimatology
DE: 1878 Water/energy interactions (0495)
SC: Hydrology [H]
MN: 2007 Fall Meeting