|Brooks, Erin - University Of Idaho|
|Goodrich, David - Dave|
|Okalebo, Jane - University Of Nebraska|
|Moorman, Thomas - Tom|
|Hamilton, Stephen - Michigan State University|
|Bosch, David - Dave|
|Saha, Amartya - Archbold Biological Station|
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/14/2018
Publication Date: 7/29/2018
Citation: Baffaut, C., Brooks, E., Pierson Jr, F.B., Demaria, E.M., Goodrich, D.C., Elias, E.H., Hoover, D.L., Liebig, M.A., Moriasi, D.N., Harmel, R.D., Smith, D.R., Okalebo, J.A., Moorman, T.B., Yasarer, L.M., Hamilton, S.K., Bosch, D.D., King, K.W., Saha, A.K., Buda, A.R., Mccarty, G.W. 2018. Uncertainty of water budget closure across the Long-Term Agroecosystems Research network. ASABE Annual International Meeting, July 29-Auguast 1, 2018, Detroit, Michigan. Paper #1800938.
Technical Abstract: Quantification of the various components of the hydrologic budget at a site (precipitation, evaporation, runoff,…) gives important indications about major and minor hydrologic processes controlling field and watershed scale response. The objectives of this study were to: 1) develop hydrologic budgets for watersheds (> 400 ha) and/or fields (< 100 ha) at the 18 USDA Long-Term Agroecosystems Research (LTAR) network sites using measured data, model estimates, and/or relevant published literature values, for periods ranging from 2 to 50 years, and 2) quantify the uncertainty of these fluxes and the uncertainty with which the water balance can be closed. Uncertainty of each component was quantified based on measurement or estimation techniques, published literature, and years of data available. Propagation of uncertainties utilized the quadrature formula. Closure uncertainties ranged from 11% to 62%. Factors that contributed to small (<20%) water balance closure uncertainties included humid environments, long data sets (>10years), measurement or estimation of each water budget component, and filling-in of missing data. Errors were greater (>30%) in semi-arid environments and when components were not fully measured or estimated over a long period. At some sites, model estimates of non-measured variables helped close the water balance and reduce the uncertainty of the water balance closure. Detection and understanding of changes in the hydrologic budget at a site requires long measurement periods and appropriate data post-processing methods.