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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #403639

Research Project: Dryland and Irrigated Crop Management Under Limited Water Availability and Drought

Location: Soil and Water Management Research

Title: Lessons learned from two decades of eddy covariance and large weighing lysimeter comparisons

item Evett, Steven - Steve
item LIN, XIAOMAO - Kansas State University
item Marek, Gary
item Brauer, David
item Copeland, Karen
item Ruthardt, Brice

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/31/2023
Publication Date: 10/24/2023
Citation: Evett, S.R., Lin, X., Marek, G.W., Brauer, D.K., Copeland, K.S., Ruthardt, B.B. 2023. Lessons learned from two decades of eddy covariance and large weighing lysimeter comparisons [abstract]. ASABE 2nd Global ET Symposium, October 23-27, 2023. Paper No. 23042.

Interpretive Summary:

Technical Abstract: Sensing of air temperature, humidity, and wind speed in the atmosphere above vegetation has been used in various ways to characterize evaporative fluxes from vegetated surfaces, often in combination with sensing of radiative fluxes. Techniques employed include aerodynamic profiling, Bowen ratio, and eddy covariance (EC). All of these techniques have the advantage that sensing of soil water storage changes is not required, so they can be used in situations where weighing lysimeters are not viable for direct measurement of evapotranspiration (ET) or where deep soil water sensing is incapable of closing the water balance. Of these, the EC technique has become globally used in flux networks and is frequently applied above cropped surfaces to characterize ET. However, all of the flux sensing methods have disadvantages as well. Because they sense fluxes in the atmosphere above a crop, they are indirect measures of ET, the loss of water from the soil and plant. Flux divergence, atmospheric stability issues, heat storage, and other issues contribute to a common lack of agreement between ET as calculated from flux sensing and ET determined directly using weighing lysimeters. Here we review the results of more than two decades of studies comparing ET determined using flux sensing methods to ET determined by large weighing lysimeters in the semi-arid environment of the U.S. Southern High Plains at Bushland, Texas.