44 A New Tool for Direct Evapotranspiration Measurements

Wednesday, 3 May 2023
Scandinavian Ballroom Salon 3 (Royal Sonesta Minneapolis Downtown )
William Miller, LI-COR, LINCOLN, NE; and G. Fratini, J. McCoy, R. Walbridge, D. Trutna, A. Parr, K. Gerot, A. Frodyma, I. Fuhrman, L. Xu, and G. Burba

Declining water availability in combination with increasing food demand is among the key global concerns in modern society. These two opposing dynamics manifest uniquely at different scales, from the farm field to global food distribution, and require innovative composite solutions in terms of policy, education, science, and technology.

Recent decades have seen the proliferation of multiple large-scale eddy covariance tower networks (e.g., AmeriFlux, AsiaFlux, ChinaFlux, ICOS, JapanFlux, LTER, NEON, OzFlux), consisting of nearly 2155 past and currently operating sites worldwide. These networks show great potential to advance our understanding of ecology in a changing world.

To date ecological research utilizing these vast networks has largely focused on carbon fluxes, even though most of these sites also measure latent heat flux and evapotranspiration. Moreover, these flux measurements are infrequently paired with other water cycle measurements such as soil moisture, plant water potential, or water table dynamics. Such measurements can be collected at scales ranging from individual to ecosystems and are necessary to advance our understanding of the coupling of carbon and water cycles, in addition to the changes to hydrology imposed by climate change.

Cutting-edge technologies to assess water use on ecosystem-level scales have been actively developed in academia, and have recently led to the development of next-generation fully-automated evapotranspiration stations and networks which can effectively and efficiently handle “big data” on water use coming from a grid of measurement stations. This data can provide high spatial and temporal coverage of water usage on multiple scales, ranging from a single watershed to a region, state, or a continent.

In this presentation, we will focus on the main features and specifications of the very latest technology and the explanation of the latest scientific assessment methods available for direct, field-scale, unattended, and automated measurements of evapotranspiration.
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