Water Resources Research Act Program

Details for Project ID 2014MT289B

Student Fellowship: Estimating Evapotranspiration at the Regional Scale: An Energy Balance Approach

Institute: Montana
Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $2,000 Total Non-Federal Funds: $880

Principal Investigators: Aiden Johnson, Aiden Johnson

Project Summary: Of particular importance to water management in Montana is the quantification of evapotranspiration (ET) in arid and semiarid systems where water is scarce, including most of Montanas agricultural regions. Quantifying ET at both the field scale and the basin scale could lead to changes in farming practices that conserve water use and help optimize fertilizer application rates and timing while protecting water quality. ET changes dynamically across space and time; therefore, quantifying these spatiotemporal dynamics is critical for accurately assessing the water balance of a field, watershed, or region. Accurately calculating actual ET is important for understanding not only water resources, but also for the dynamics of materials that are transported by water including nutrients and pollutants. Project objectives are to 1) derive the necessary variables in remote sensing data from Landsat 8 needed to solve determine net radiation balance; 2) quantify ET in the Judith River watershed and create a map displaying those values; 3) perform a Monte Carlo uncertainty analysis on regional ET map, providing a map of ET uncertainty for the Judith River watershed; 4) extrapolate analysis over the entire state of Montana making adjustments for land cover types and other confounding variables; and 5) identify uncertainties in satellite-based ET algorithms to help guide future tower-based and satellite-based studies.