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Heterogeneity Matters: Aggregation Bias of Gas Transfer Velocity Versus Energy Dissipation Rate Relations in Streams

The gas transfer velocity, [Formula: see text] , modulates gas fluxes across air‐water interfaces in rivers. While the theory postulates a local scaling law between [Formula: see text] and the turbulent kinetic energy dissipation rate [Formula: see text] , empirical studies usually interpret this re...

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Detalles Bibliográficos
Autores principales: Botter, Gianluca, Peruzzo, Paolo, Durighetto, Nicola
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9286590/
https://www.ncbi.nlm.nih.gov/pubmed/35864942
http://dx.doi.org/10.1029/2021GL094272
Descripción
Sumario:The gas transfer velocity, [Formula: see text] , modulates gas fluxes across air‐water interfaces in rivers. While the theory postulates a local scaling law between [Formula: see text] and the turbulent kinetic energy dissipation rate [Formula: see text] , empirical studies usually interpret this relation at the reach‐scale. Here, we investigate how local [Formula: see text] laws can be integrated along heterogeneous reaches exploiting a simple hydrodynamic model, which links stage and velocity to the local slope. The model is used to quantify the relative difference between the gas transfer velocity of a heterogeneous stream and that of an equivalent homogeneous system. We show that this aggregation bias depends on the exponent of the local scaling law, [Formula: see text] , and internal slope variations. In high‐energy streams, where [Formula: see text] , spatial heterogeneity of [Formula: see text] significantly enhances reach‐scale values of [Formula: see text] as compared to homogeneous settings. We conclude that small‐scale hydro‐morphological traits bear a profound impact on gas evasion from inland waters.