title: WATER RESOURCES. Hydrologic connectivity constrains partitioning of global terrestrial water fluxes.
abstract: Continental precipitation not routed to the oceans as runoff returns to the atmosphere as evapotranspiration. Partitioning this evapotranspiration flux into interception, transpiration, soil evaporation, and surface water evaporation is difficult using traditional hydrological methods, yet critical for understanding the water cycle and linked ecological processes. We combined two large-scale flux-partitioning approaches to quantify evapotranspiration subcomponents and the hydrologic connectivity of bound, plant-available soil waters with more mobile surface waters. Globally, transpiration is 64 ± 13% (mean ± 1 standard deviation) of evapotranspiration, and 65 ± 26% of evaporation originates from soils and not surface waters. We estimate that 38 ± 28% of surface water is derived from the plant-accessed soil water pool. This limited connectivity between soil and surface waters fundamentally structures the physical and biogeochemical interactions of water transiting through catchments.
authors.affiliation: Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA. Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Good
authors.affiliation: College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
authors.forename: David
authors.initials: D
authors.lastname: Noone
authors.affiliation: Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA. Global Change and Sustainability Center, University of Utah, Salt Lake City, UT, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Bowen