The Science

This is one of the first studies that comprehensively investigated the spatiotemporal variations of evapotranspiration (ET) in a mountainous watershed and analyzed the factors that control these variations.

The Impact

This study presents a promising approach to the assessment of ET with a high spatiotemporal resolution over watershed scales and investigates factors controlling ET spatiotemporal variations.

Summary

ET is a key component of the water balance, which influences hydrometeorology, water resources, carbon and other biogeochemical cycles, and ecosystem diversity. Researchers conducted a study to investigate the spatiotemporal variations of ET at the East River watershed in Colorado and analyze the factors that control these variations. Simulation results showed that 55% of annual precipitation in the East River is lost to ET, and that 75% of the ET is during the summer months (May to September). Researchers also found that the contribution of transpiration to the total ET was ~50%, which is much larger than that of soil evaporation (32%) and canopy evaporation (18%). Spatial analysis indicated that the ET is higher at elevations of 2950–3200 m and lower along the river valley (<2750 m) and at the high elevations (>3900 m). A correlation analysis of factors affecting ET showed that the land elevation, air temperature, and vegetation are closely correlated, and together they govern the ET spatial variability. The results also suggested that ET in areas with more finely textured soil is slightly larger than regions with coarse-texture soil.

Principal Investigator

Susan Hubbard
Lawrence Berkeley National Laboratory
sshubbard@lbl.gov

Program Manager

Jennifer Arrigo
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
jennifer.arrigo@science.doe.gov

Funding

This work was supported by the U.S. Department of Energy, Office of Science, Biological and Environmental Research (BER) Program.

References