Coupling of the Surface and Near‐Bottom Currents in the Gulf of Mexico
| Autor: | Yingli Zhu, Xinfeng Liang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Baroclinity Subsurface currents surface currents Oceanography 01 natural sciences Deep sea Loop Current Geostrophic current Geochemistry and Petrology Currents Earth and Planetary Sciences (miscellaneous) coupling Loop Current eddies Research Articles 0105 earth and related environmental sciences Gulf of Mexico near‐bottom currents Ocean current Rossby wave Geophysics Sea-surface height Eddy Space and Planetary Science Geology Oceanography: Physical Research Article |
| Zdroj: | Journal of Geophysical Research. Oceans |
| ISSN: | 2169-9291 2169-9275 |
| Popis: | Coupling between the surface and near‐bottom currents in the Gulf of Mexico (GoM) has been reported in many case studies. However, geographical variations of this coupling need more examination. In this study, surface geostrophic currents derived from satellite‐observed sea surface height and subsurface currents from a collection of deep ocean moorings are used to examine the surface and bottom coupling in different parts of the GoM. The short‐period (30–90 days) fluctuations generated by the Loop Current (LC) and the LC eddies (LCEs) have a more vertically coherent structure and stronger deep ocean expressions than the long‐period fluctuations (>90 days). In addition, the strength of the coupling is modulated by the long‐period variations of the LC and LCE sheddings. Moreover, the surface and bottom coupling varies geographically. In the LC region, the surface fluctuations along the eastern side of the LC are important in causing the bottom current fluctuations through baroclinic instability under the LC and through traveling topographic Rossby waves (TRWs) north of the LC. In the central deep GoM, the bottom currents are affected by the upper fluctuations of the northern LC through both local baroclinic instability and remote TRW propagation. In the northwestern GoM, the bottom current fluctuations are largely related to the remote surface variability from the west side of the LC by TRWs propagating northwestward. This study will help us better understand mechanisms of the bottom current fluctuations that are important for the dispersal of deep ocean materials and properties. Key Points Surface and bottom currents in the Gulf of Mexico can be coupled locally by baroclinic instability and remotely by topographic Rossby wavesFluctuations generated along the Loop Current have stronger deep ocean expressions at the period of 30–90 days than at longer periodsSurface and bottom coupling in the Gulf of Mexico varies geographically and is modulated by the Loop Current and the Loop Current eddies |
| Databáze: | OpenAIRE |
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