Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake
In this study we analyzed turbulent heat fluxes over a seasonal ice cover on a boreal lake located in southern Finland. Eddy covariance (EC) flux measurements of sensible ( H ) and latent heat ( L E ) from four ice-on seasons between 2014 and 2019 are compared to three different bulk transfer models...
Published in: | Geoscientific Model Development |
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Online Access: | https://doi.org/10.5194/gmd-15-4739-2022 https://gmd.copernicus.org/articles/15/4739/2022/ |
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ftcopernicus:oai:publications.copernicus.org:gmd96718 2023-05-15T18:18:41+02:00 Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake Ala-Könni, Joonatan Kohonen, Kukka-Maaria Leppäranta, Matti Mammarella, Ivan 2022-06-21 application/pdf https://doi.org/10.5194/gmd-15-4739-2022 https://gmd.copernicus.org/articles/15/4739/2022/ eng eng doi:10.5194/gmd-15-4739-2022 https://gmd.copernicus.org/articles/15/4739/2022/ eISSN: 1991-9603 Text 2022 ftcopernicus https://doi.org/10.5194/gmd-15-4739-2022 2022-06-27T16:22:42Z In this study we analyzed turbulent heat fluxes over a seasonal ice cover on a boreal lake located in southern Finland. Eddy covariance (EC) flux measurements of sensible ( H ) and latent heat ( L E ) from four ice-on seasons between 2014 and 2019 are compared to three different bulk transfer models: one with a constant transfer coefficient and two with stability-adjusted transfer coefficients: the Lake Heat Flux Analyzer and SEA-ICE. All three models correlate well with the EC results in general while typically underestimating the magnitude and the standard deviation of the flux in comparison to the EC observations. Differences between the models are small, with the constant transfer coefficient model performing slightly better than the stability-adjusted models. Small difference in temperature and humidity between surface and air results in low correlation between models and EC. During melting periods (surface temperature T 0 >0 ∘ C), the model performance for L E decreases when compared to the freezing periods ( T 0 <0 ∘ C), while the opposite is true for H . At low wind speed, EC shows relatively high fluxes ( ±20 W m −2 ) for H and L E due to non-local effects that the bulk models are not able to reproduce. The complex topography of the lake surroundings creates local violations of the Monin–Obukhov similarity theory, which helps explain this counterintuitive result. Finally, the uncertainty in the estimation of the surface temperature and humidity affects the bulk heat fluxes, especially when the differences between surface and air values are small. Text Sea ice Copernicus Publications: E-Journals Boreal Lake ENVELOPE(-127.670,-127.670,58.802,58.802) Geoscientific Model Development 15 12 4739 4755 |
institution |
Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
In this study we analyzed turbulent heat fluxes over a seasonal ice cover on a boreal lake located in southern Finland. Eddy covariance (EC) flux measurements of sensible ( H ) and latent heat ( L E ) from four ice-on seasons between 2014 and 2019 are compared to three different bulk transfer models: one with a constant transfer coefficient and two with stability-adjusted transfer coefficients: the Lake Heat Flux Analyzer and SEA-ICE. All three models correlate well with the EC results in general while typically underestimating the magnitude and the standard deviation of the flux in comparison to the EC observations. Differences between the models are small, with the constant transfer coefficient model performing slightly better than the stability-adjusted models. Small difference in temperature and humidity between surface and air results in low correlation between models and EC. During melting periods (surface temperature T 0 >0 ∘ C), the model performance for L E decreases when compared to the freezing periods ( T 0 <0 ∘ C), while the opposite is true for H . At low wind speed, EC shows relatively high fluxes ( ±20 W m −2 ) for H and L E due to non-local effects that the bulk models are not able to reproduce. The complex topography of the lake surroundings creates local violations of the Monin–Obukhov similarity theory, which helps explain this counterintuitive result. Finally, the uncertainty in the estimation of the surface temperature and humidity affects the bulk heat fluxes, especially when the differences between surface and air values are small. |
format |
Text |
author |
Ala-Könni, Joonatan Kohonen, Kukka-Maaria Leppäranta, Matti Mammarella, Ivan |
spellingShingle |
Ala-Könni, Joonatan Kohonen, Kukka-Maaria Leppäranta, Matti Mammarella, Ivan Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
author_facet |
Ala-Könni, Joonatan Kohonen, Kukka-Maaria Leppäranta, Matti Mammarella, Ivan |
author_sort |
Ala-Könni, Joonatan |
title |
Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
title_short |
Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
title_full |
Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
title_fullStr |
Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
title_full_unstemmed |
Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
title_sort |
validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake |
publishDate |
2022 |
url |
https://doi.org/10.5194/gmd-15-4739-2022 https://gmd.copernicus.org/articles/15/4739/2022/ |
long_lat |
ENVELOPE(-127.670,-127.670,58.802,58.802) |
geographic |
Boreal Lake |
geographic_facet |
Boreal Lake |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1991-9603 |
op_relation |
doi:10.5194/gmd-15-4739-2022 https://gmd.copernicus.org/articles/15/4739/2022/ |
op_doi |
https://doi.org/10.5194/gmd-15-4739-2022 |
container_title |
Geoscientific Model Development |
container_volume |
15 |
container_issue |
12 |
container_start_page |
4739 |
op_container_end_page |
4755 |
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1766195335891255296 |