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Research article - Peer-reviewed, 2020

Challenges of predicting gas transfer velocity from wind measurements over global lakes

Klaus, Marcus; Vachon, Dominic

Abstract

Estimating air-water gas transfer velocities (k) is integral to understand biogeochemical and ecological processes in aquatic systems. In lakes, k is commonly predicted using wind-based empirical models, however, their predictive performance under conditions that differ from their original calibration remains largely unassessed. Here, we collected 2222 published k estimates derived from various methods in 46 globally distributed lakes to (1) evaluate the predictions of a selection of six available wind-speed based k models for lakes and (2) explore and develop new empirical models to predict k over global lakes. We found that selected k models generally performed poorly in predicting k in lakes. Model predictions were more accurate than simply assuming a mean k in only 2-39% of all lakes, however, we could not identify with confidence the specific conditions in which some models outperformed others. We developed new wind-based models in which additional variables describing the spatial coverage of k estimates and the lake size and shape had a significant effect on the wind speed-k relationship. Although these new models did not fit the global dataset significantly better than previous k models, they generate overall less biased predictions for global lakes. We further provide explicit estimates of prediction errors that integrate methodological and lake-specific uncertainties. Our results highlight the potential limits when using wind-based models to predict k across lakes and urge scientists to properly account for prediction errors, or measure k directly in the field whenever possible.

Keywords

Air-water gas exchange; Model assessment; Lake gas flux; Wind speed; k(600); Reaeration

Published in

Aquatic Sciences - Research Across Boundaries
2020, volume: 82, number: 3, article number: 53
Publisher: SPRINGER BASEL AG

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Umeå University
Vachon, Dominic
Umea Univ

UKÄ Subject classification

Oceanography, Hydrology, Water Resources

Publication Identifiers

DOI: https://doi.org/10.1007/s00027-020-00729-9

URI (permanent link to this page)

https://res.slu.se/id/publ/105608