Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake
Abstract Parameterizations for bottom shear stress are required to predict sediment resuspension from field observations and within numerical models that do not resolve flow within the viscous sublayer. This study assessed three observation‐based bottom shear stress (τb) parameterizations, including...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2023-06-01
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| Series: | Earth and Space Science |
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| Online Access: | https://doi.org/10.1029/2022EA002786 |
| _version_ | 1797793301966880768 |
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| author | S. Lin L. Boegman A. Jabbari R. Valipour Y. Zhao |
| author_facet | S. Lin L. Boegman A. Jabbari R. Valipour Y. Zhao |
| author_sort | S. Lin |
| collection | DOAJ |
| description | Abstract Parameterizations for bottom shear stress are required to predict sediment resuspension from field observations and within numerical models that do not resolve flow within the viscous sublayer. This study assessed three observation‐based bottom shear stress (τb) parameterizations, including (a) the sum of surface wave stress and mean current (quadratic) stress (τb=τw+τc ${ au }_{b}={{ au }_{w}+ au }_{c}$); (b) the log‐law (τb = τL); and (c) the turbulent kinetic energy (τb = τTKE); using 2 years of observations from a large shallow lake. For this system, the parameterization τb = τw + τc was sufficient to qualitatively predict resuspension, since bottom currents and surface wave orbitals were the two major processes found to resuspend bottom sediments. However, the τL and τTKE parameterizations also captured the development of a nepheloid layer within the hypolimnion associated with high‐frequency internal waves. Reynolds‐averaged Navier‐Stokes (RANS) equation models parameterize τb as the summation of modeled current‐induced bottom stress (τc,m) and modeled surface wave‐induced bottom stress (τw,m). The performance of different parameterizations for τw,m and τc,m in RANS models was assessed against the observations. The optimal parameterizations yielded root‐mean‐square errors of 0.031 and 0.025 Pa, respectively, when τw,m, and τc,m were set using a constant canonical drag coefficient. A RANS‐based τL parameterization was developed; however, the grid‐averaged modeled dissipation did not always match local observations, leading to O(10) errors in prediction of bottom stress. Turbulence‐based parameterizations should be further developed for application to flows with mean shear‐free boundary turbulence. |
| first_indexed | 2024-03-13T02:46:20Z |
| format | Article |
| id | doaj.art-553090cc861540589b6006578d57b474 |
| institution | Directory Open Access Journal |
| issn | 2333-5084 |
| language | English |
| last_indexed | 2024-03-13T02:46:20Z |
| publishDate | 2023-06-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Earth and Space Science |
| spelling | doaj.art-553090cc861540589b6006578d57b4742023-06-28T17:34:35ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842023-06-01106n/an/a10.1029/2022EA002786Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow LakeS. Lin0L. Boegman1A. Jabbari2R. Valipour3Y. Zhao4Environmental Fluid Dynamics Laboratory Queen's University Kingston ON CanadaEnvironmental Fluid Dynamics Laboratory Queen's University Kingston ON CanadaFisheries and Oceans Canada Bedford Institute of Oceanography Dartmouth NS CanadaCanada Centre for Inland Waters Environment and Climate Change Canada Burlington ON CanadaAquatic Research and Monitoring Section Ontario Ministry of Natural Resources and Forestry Lake Erie Fishery Station Wheatley ON CanadaAbstract Parameterizations for bottom shear stress are required to predict sediment resuspension from field observations and within numerical models that do not resolve flow within the viscous sublayer. This study assessed three observation‐based bottom shear stress (τb) parameterizations, including (a) the sum of surface wave stress and mean current (quadratic) stress (τb=τw+τc ${ au }_{b}={{ au }_{w}+ au }_{c}$); (b) the log‐law (τb = τL); and (c) the turbulent kinetic energy (τb = τTKE); using 2 years of observations from a large shallow lake. For this system, the parameterization τb = τw + τc was sufficient to qualitatively predict resuspension, since bottom currents and surface wave orbitals were the two major processes found to resuspend bottom sediments. However, the τL and τTKE parameterizations also captured the development of a nepheloid layer within the hypolimnion associated with high‐frequency internal waves. Reynolds‐averaged Navier‐Stokes (RANS) equation models parameterize τb as the summation of modeled current‐induced bottom stress (τc,m) and modeled surface wave‐induced bottom stress (τw,m). The performance of different parameterizations for τw,m and τc,m in RANS models was assessed against the observations. The optimal parameterizations yielded root‐mean‐square errors of 0.031 and 0.025 Pa, respectively, when τw,m, and τc,m were set using a constant canonical drag coefficient. A RANS‐based τL parameterization was developed; however, the grid‐averaged modeled dissipation did not always match local observations, leading to O(10) errors in prediction of bottom stress. Turbulence‐based parameterizations should be further developed for application to flows with mean shear‐free boundary turbulence.https://doi.org/10.1029/2022EA002786bottom shear stressturbulent kinetic energyReynolds‐averaged Navier‐Stokes equation modelssediment resuspensionlarge shallow lake |
| spellingShingle | S. Lin L. Boegman A. Jabbari R. Valipour Y. Zhao Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake Earth and Space Science bottom shear stress turbulent kinetic energy Reynolds‐averaged Navier‐Stokes equation models sediment resuspension large shallow lake |
| title | Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake |
| title_full | Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake |
| title_fullStr | Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake |
| title_full_unstemmed | Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake |
| title_short | Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake |
| title_sort | observation and parameterization of bottom shear stress and sediment resuspension in a large shallow lake |
| topic | bottom shear stress turbulent kinetic energy Reynolds‐averaged Navier‐Stokes equation models sediment resuspension large shallow lake |
| url | https://doi.org/10.1029/2022EA002786 |
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