The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico
Mesoscale eddies and fronts in the ocean greatly impact lateral transport and in turn the trajectories of sinking particles. Such influence was explored for April and October 2012 in the Gulf of Mexico using numerical simulations performed with a regional model at 1-km horizontal resolution. Results...
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| Format: | Article |
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BioOne
2018-04-01
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| Series: | Elementa: Science of the Anthropocene |
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| Online Access: | https://www.elementascience.org/articles/292 |
| _version_ | 1819059855818752000 |
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| author | Guangpeng Liu Annalisa Bracco Uta Passow |
| author_facet | Guangpeng Liu Annalisa Bracco Uta Passow |
| author_sort | Guangpeng Liu |
| collection | DOAJ |
| description | Mesoscale eddies and fronts in the ocean greatly impact lateral transport and in turn the trajectories of sinking particles. Such influence was explored for April and October 2012 in the Gulf of Mexico using numerical simulations performed with a regional model at 1-km horizontal resolution. Results are compared qualitatively to field samples from two sediment traps located at GC600 (27°22.5 N, 90°30.7 W) and AT357 (27°31.5 N, 89°42.6 W), 81 km apart. In April the traps collected a comparable amount of material, while in October the flux at GC600 greatly exceeded that at AT357. Through inverse calculations, several thousand particle trajectories were reconstructed multiple times from the ocean surface to the depth of the traps (approximately 1,000 m) using a range of sinking velocities, 20–100 m d–1. Taken together, model results and trap data indicate that cross-shore transport of riverine input induced by mesoscale eddies, and convergence and divergence processes at the scale of a few kilometers, significantly impact the trajectory of sinking particles. The large majority of modeled particles reach the bottom faster than would be expected by their sinking speeds alone. This finding is associated with submesoscale-induced horizontal convergence in the mixed layer that aggregates particles preferentially in downwelling regions, accelerating their descent. Furthermore, this study confirms that the cone of influence of vertical fluxes is highly variable in both space and time in the presence of an energetic eddy field, especially for particles with sinking velocity of 50 m d–1 or less. It also demonstrates that the variability of vertical fluxes in the Gulf of Mexico is highly complex and can be understood only by considering the mesoscale circulation and seasonal cycle of primary productivity, which in turn are linked to riverine inputs, wind forcing and the seasonal cycle of the mixed-layer depth. |
| first_indexed | 2024-12-21T14:17:44Z |
| format | Article |
| id | doaj.art-3344720615cb4bcd90fc3e7bcc74a8ba |
| institution | Directory Open Access Journal |
| issn | 2325-1026 |
| language | English |
| last_indexed | 2024-12-21T14:17:44Z |
| publishDate | 2018-04-01 |
| publisher | BioOne |
| record_format | Article |
| series | Elementa: Science of the Anthropocene |
| spelling | doaj.art-3344720615cb4bcd90fc3e7bcc74a8ba2022-12-21T19:00:52ZengBioOneElementa: Science of the Anthropocene2325-10262018-04-016110.1525/elementa.292261The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of MexicoGuangpeng Liu0Annalisa Bracco1Uta Passow2School of Earth and Atmospherics Sciences, Georgia Institute of Technology, Atlanta, GeorgiaSchool of Earth and Atmospherics Sciences, Georgia Institute of Technology, Atlanta, GeorgiaMarine Science Institute, University of California Santa Barbara, CaliforniaMesoscale eddies and fronts in the ocean greatly impact lateral transport and in turn the trajectories of sinking particles. Such influence was explored for April and October 2012 in the Gulf of Mexico using numerical simulations performed with a regional model at 1-km horizontal resolution. Results are compared qualitatively to field samples from two sediment traps located at GC600 (27°22.5 N, 90°30.7 W) and AT357 (27°31.5 N, 89°42.6 W), 81 km apart. In April the traps collected a comparable amount of material, while in October the flux at GC600 greatly exceeded that at AT357. Through inverse calculations, several thousand particle trajectories were reconstructed multiple times from the ocean surface to the depth of the traps (approximately 1,000 m) using a range of sinking velocities, 20–100 m d–1. Taken together, model results and trap data indicate that cross-shore transport of riverine input induced by mesoscale eddies, and convergence and divergence processes at the scale of a few kilometers, significantly impact the trajectory of sinking particles. The large majority of modeled particles reach the bottom faster than would be expected by their sinking speeds alone. This finding is associated with submesoscale-induced horizontal convergence in the mixed layer that aggregates particles preferentially in downwelling regions, accelerating their descent. Furthermore, this study confirms that the cone of influence of vertical fluxes is highly variable in both space and time in the presence of an energetic eddy field, especially for particles with sinking velocity of 50 m d–1 or less. It also demonstrates that the variability of vertical fluxes in the Gulf of Mexico is highly complex and can be understood only by considering the mesoscale circulation and seasonal cycle of primary productivity, which in turn are linked to riverine inputs, wind forcing and the seasonal cycle of the mixed-layer depth.https://www.elementascience.org/articles/292mesoscale and submesoscalesinking particlesROMSthe Gulf of Mexico |
| spellingShingle | Guangpeng Liu Annalisa Bracco Uta Passow The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico Elementa: Science of the Anthropocene mesoscale and submesoscale sinking particles ROMS the Gulf of Mexico |
| title | The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico |
| title_full | The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico |
| title_fullStr | The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico |
| title_full_unstemmed | The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico |
| title_short | The influence of mesoscale and submesoscale circulation on sinking particles in the northern Gulf of Mexico |
| title_sort | influence of mesoscale and submesoscale circulation on sinking particles in the northern gulf of mexico |
| topic | mesoscale and submesoscale sinking particles ROMS the Gulf of Mexico |
| url | https://www.elementascience.org/articles/292 |
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