Mesoscale and Submesoscale Processes in the Southeast Atlantic and Their Impact on the Regional Thermohaline Structure
| Autor: | Bruno Blanke, Sabrina Speich, Xavier Carton, Tonia Astrid Capuano |
|---|---|
| Přispěvatelé: | Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Water mass
meso- and submesoscale dynamics 010504 meteorology & atmospheric sciences Baroclinity Mesoscale meteorology Oceanography 01 natural sciences Indo-Atlantic exchange Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) 14. Life underwater ComputingMilieux_MISCELLANEOUS 0105 earth and related environmental sciences [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere 010505 oceanography Ocean current Cape Basin water masses Geophysics Eddy 13. Climate action Space and Planetary Science [SDU]Sciences of the Universe [physics] Mode water Thermohaline circulation Thermocline Geology |
| Zdroj: | Journal of Geophysical Research. Oceans Journal of Geophysical Research. Oceans, 2018, 123 (3), pp.1937-1961. ⟨10.1002/2017JC013396⟩ Journal of Geophysical Research. Oceans, Wiley-Blackwell, 2018, 123 (3), pp.1937-1961. ⟨10.1002/2017JC013396⟩ Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2018-03, Vol. 123, N. 3, P. 1937-1961 |
| ISSN: | 2169-9275 2169-9291 |
| Popis: | The turbulent processes in the Cape Basin, the southeasternmost gate of the Atlantic Ocean, play a key role in the transport and mixing of upper to intermediate water masses entering the area from the Indian Ocean, making them especially relevant for the Indo-Atlantic transfer of heat and salt. In this paper, two numerical simulations at different horizontal resolutions are used to study mesoscale and submesoscale dynamics, their phenomenology, their evolution, and their impact on the local water masses. Submesoscale processes seasonally affect both, the upper and intermediate layers, but there are clear dynamical differences between the two layers. Several types of instabilities underline this spatial and temporal variability. Near the surface, mixed layer instabilities occur during winter, while mesoscale-driven instabilities, as the symmetric type, prevail in summer. The connection between these two seasonal regimes is ensured, in anticyclonic eddies and within the mixed layers, by Charney baroclinic instabilities, involved in the local formation and subduction of mode water, that we have dubbed as Agulhas Rings mode water. Intermediate depths are instead characterized by mesoscale mechanisms of density compensation and lateral stirring of the tracer variance, triggering a significant filamentogenesis whose vertical scales are comparable to those mentioned in previous studies. This leads to a particularly efficient mixing of Antarctic Intermediate Waters of Indian and Atlantic origins. Lagrangian estimates highlight the new and significant role of fine scale structures in setting the water masses properties of upper and lower thermocline waters materializing the Indo-Atlantic exchange and therefore potentially affecting the global ocean circulation. |
| Databáze: | OpenAIRE |
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