Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries
This study presents a comparison of forcings between density gradient and tides in idealized funnel-shaped salt-plug estuaries. Three-dimensional numerical model results also examine longitudinal and lateral circulations. In salt-plug estuaries, a positive longitudinal estuarine circulation is obser...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-04-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1152625/full |
| _version_ | 1797837815517544448 |
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| author | Seyed Taleb Hosseini Emil Stanev Johannes Pein Arnoldo Valle-Levinson Corinna Schrum Corinna Schrum |
| author_facet | Seyed Taleb Hosseini Emil Stanev Johannes Pein Arnoldo Valle-Levinson Corinna Schrum Corinna Schrum |
| author_sort | Seyed Taleb Hosseini |
| collection | DOAJ |
| description | This study presents a comparison of forcings between density gradient and tides in idealized funnel-shaped salt-plug estuaries. Three-dimensional numerical model results also examine longitudinal and lateral circulations. In salt-plug estuaries, a positive longitudinal estuarine circulation is observed landward of a salinity maximum zone or salt plug. Seaward of the salt plug, the estuary shows an inverse circulation cell. The longitudinal flows show a fortnightly variability inside the salt plug. Also, the salt plug is saltier in spring tides than in neap tidal cycles mainly owing to higher landward salt transport by tidal advection during the spring tides. The lateral circulation and divergence dv/dy have the influence of Coriolis acceleration. In the absence of Earth’s rotation, the tidally averaged lateral circulations have nearly the same directions within the positive and inverse cells. Directions of lateral flow reverse in the salt-plug area. Inside this area, the lateral circulation also shows clear neap–spring variability, including downwelling cells during spring tides and upwelling in neap tides. The salinity maximum zone exhibits a vertically homogeneous condition particularly in meso-tidal salt-plug estuaries. Finally, this study introduces the threshold of “log(tidal Froude number)=3” (tidal forcing 3 orders of magnitude ≥ density gradients) for salt-plug estuaries as the condition under which the tidal forcing can overcome the density gradient, and consequently salinity inside the salt plug zone is reinforced by tides with a landward movement. This robust salinity maximum zone is also identified by a high Ekman number (log(Ekman number)>0.25). |
| first_indexed | 2024-04-09T15:31:51Z |
| format | Article |
| id | doaj.art-07f2529e480c4b298086db2fdc258b9a |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-09T15:31:51Z |
| publishDate | 2023-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-07f2529e480c4b298086db2fdc258b9a2023-04-28T05:51:16ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-04-011010.3389/fmars.2023.11526251152625Longitudinal and lateral circulation and tidal impacts in salt-plug estuariesSeyed Taleb Hosseini0Emil Stanev1Johannes Pein2Arnoldo Valle-Levinson3Corinna Schrum4Corinna Schrum5Institute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, GermanyInstitute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, GermanyInstitute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, GermanyDepartment of Civil and Coastal Engineering, University of Florida, Gainesville, FL, United StatesInstitute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, GermanyInstitute of Oceanography, Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, GermanyThis study presents a comparison of forcings between density gradient and tides in idealized funnel-shaped salt-plug estuaries. Three-dimensional numerical model results also examine longitudinal and lateral circulations. In salt-plug estuaries, a positive longitudinal estuarine circulation is observed landward of a salinity maximum zone or salt plug. Seaward of the salt plug, the estuary shows an inverse circulation cell. The longitudinal flows show a fortnightly variability inside the salt plug. Also, the salt plug is saltier in spring tides than in neap tidal cycles mainly owing to higher landward salt transport by tidal advection during the spring tides. The lateral circulation and divergence dv/dy have the influence of Coriolis acceleration. In the absence of Earth’s rotation, the tidally averaged lateral circulations have nearly the same directions within the positive and inverse cells. Directions of lateral flow reverse in the salt-plug area. Inside this area, the lateral circulation also shows clear neap–spring variability, including downwelling cells during spring tides and upwelling in neap tides. The salinity maximum zone exhibits a vertically homogeneous condition particularly in meso-tidal salt-plug estuaries. Finally, this study introduces the threshold of “log(tidal Froude number)=3” (tidal forcing 3 orders of magnitude ≥ density gradients) for salt-plug estuaries as the condition under which the tidal forcing can overcome the density gradient, and consequently salinity inside the salt plug zone is reinforced by tides with a landward movement. This robust salinity maximum zone is also identified by a high Ekman number (log(Ekman number)>0.25).https://www.frontiersin.org/articles/10.3389/fmars.2023.1152625/fullsalinity maximum zoneEkman numbertidal Froude numbertidal advectionsalt fluxPersian Gulf |
| spellingShingle | Seyed Taleb Hosseini Emil Stanev Johannes Pein Arnoldo Valle-Levinson Corinna Schrum Corinna Schrum Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries Frontiers in Marine Science salinity maximum zone Ekman number tidal Froude number tidal advection salt flux Persian Gulf |
| title | Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries |
| title_full | Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries |
| title_fullStr | Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries |
| title_full_unstemmed | Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries |
| title_short | Longitudinal and lateral circulation and tidal impacts in salt-plug estuaries |
| title_sort | longitudinal and lateral circulation and tidal impacts in salt plug estuaries |
| topic | salinity maximum zone Ekman number tidal Froude number tidal advection salt flux Persian Gulf |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1152625/full |
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