Estimation of historical monthly evapotranspiration rates for the conterminous U.S.
Abstract
Evapotranspiration (ET) is a major component of the hydrologic cycle, accounting for 70% of precipitation nationwide. Its accurate estimation at a range of spatial and temporal scales is thus required for quantifying accurate water budgets at these various scales, which are in turn required for a variety of water resource assessment and modeling efforts. Because of the complexity of the processes underlying ET (e.g., transpiration, evaporation from soil moisture), the level of theoretical uncertainty in its prediction is significant, and a range of mostly empirical theoretical formulations is currently in use. ET data available at different spatial scales include (1) water balance data in which ET is estimated as a missing volume between precipitation and stream discharge (watershed scale), (2) eddy covariance data from flux towers (point scale), and (3) remotely sensed data based on energy balance calculations (km-scale). Here we present initial results of work that makes use of these data sources within a particle filter data assimilation method to estimate monthly, km-scale ET across the conterminous U.S. from 1895 to 2018. The approach includes parameter estimation and testing of different ET equations for their predictive power. The end goals of the work are to provide optimized estimates of historical to present-day monthly ET that will be useful for a variety of applications, and to inform our understanding of the performance of different ET equations as a function of time of year or region of the country.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H43I2129R
- Keywords:
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- 1816 Estimation and forecasting;
- HYDROLOGY;
- 1839 Hydrologic scaling;
- HYDROLOGY;
- 1843 Land/atmosphere interactions;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY