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 (LE) from four ice-on seasons between 2014 and 2019 are compared to three different bulk transfer models: one...
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/347504 2024-01-07T09:46:38+01:00 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 Institute for Atmospheric and Earth System Research (INAR) Micrometeorology and biogeochemical cycles 2022-08-26T14:53:06Z 17 application/pdf http://hdl.handle.net/10138/347504 eng eng COPERNICUS GESELLSCHAFT MBH 10.5194/gmd-15-4739-2022 The authors thank the ICOS-Finland (3119871), ACCC Flagship (337549) and N-PERM (341348) projects funded by the Academy of Finland. Ala-Könni , J , Kohonen , K-M , Leppäranta , M & Mammarella , I 2022 , ' Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake ' , Geoscientific Model Development , vol. 15 , no. 12 , pp. 4739-4755 . https://doi.org/10.5194/gmd-15-4739-2022 ORCID: /0000-0002-8516-3356/work/117943803 ORCID: /0000-0001-9258-1225/work/117947745 85133004510 f28eab6f-22eb-42bf-8ff3-e97de6697d10 http://hdl.handle.net/10138/347504 000813456800001 cc_by openAccess info:eu-repo/semantics/openAccess 114 Physical sciences 1171 Geosciences Article publishedVersion 2022 ftunivhelsihelda 2023-12-14T00:09:24Z 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 (LE) 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 degrees C), the model performance for LE decreases when compared to the freezing periods (T-0 < 0 degrees C), while the opposite is true for H. At low wind speed, EC shows relatively high fluxes (+/- 20 W m(-2)) for H and LE 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. Peer reviewed Article in Journal/Newspaper Sea ice HELDA – University of Helsinki Open Repository Boreal Lake ENVELOPE(-127.670,-127.670,58.802,58.802) Geoscientific Model Development 15 12 4739 4755 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
114 Physical sciences 1171 Geosciences |
spellingShingle |
114 Physical sciences 1171 Geosciences 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 |
topic_facet |
114 Physical sciences 1171 Geosciences |
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 (LE) 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 degrees C), the model performance for LE decreases when compared to the freezing periods (T-0 < 0 degrees C), while the opposite is true for H. At low wind speed, EC shows relatively high fluxes (+/- 20 W m(-2)) for H and LE 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. Peer reviewed |
author2 |
Institute for Atmospheric and Earth System Research (INAR) Micrometeorology and biogeochemical cycles |
format |
Article in Journal/Newspaper |
author |
Ala-Könni, Joonatan Kohonen, Kukka-Maaria Leppäranta, Matti Mammarella, Ivan |
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 |
publisher |
COPERNICUS GESELLSCHAFT MBH |
publishDate |
2022 |
url |
http://hdl.handle.net/10138/347504 |
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_relation |
10.5194/gmd-15-4739-2022 The authors thank the ICOS-Finland (3119871), ACCC Flagship (337549) and N-PERM (341348) projects funded by the Academy of Finland. Ala-Könni , J , Kohonen , K-M , Leppäranta , M & Mammarella , I 2022 , ' Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake ' , Geoscientific Model Development , vol. 15 , no. 12 , pp. 4739-4755 . https://doi.org/10.5194/gmd-15-4739-2022 ORCID: /0000-0002-8516-3356/work/117943803 ORCID: /0000-0001-9258-1225/work/117947745 85133004510 f28eab6f-22eb-42bf-8ff3-e97de6697d10 http://hdl.handle.net/10138/347504 000813456800001 |
op_rights |
cc_by openAccess info:eu-repo/semantics/openAccess |
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Geoscientific Model Development |
container_volume |
15 |
container_issue |
12 |
container_start_page |
4739 |
op_container_end_page |
4755 |
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1787428503085383680 |