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| Martinez, Elodie; Raapoto, Hirohiti; Maes, Christophe; Maamaatuaihutapu, Keitapu. |
| The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the... |
| Tipo: Text |
Palavras-chave: Tropical instability waves; La Nina; Chlorophyll-a concentration variability; Ocean colour; Island mass effect; Marquesas islands; Oceanography; Satellite observations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54858/56346.pdf |
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| Von Schuckmann, Karina; Brandt, P; Eden, C. |
| [1] The spatial and temporal distributions of tropical instability waves (TIWs) in the Atlantic Ocean are investigated using a combination of current observations with moored instruments deployed at the equator at 23 degrees W and a realistic eddy-resolving (1/12 degrees) general circulation model of the Atlantic Ocean. The meridional and vertical shears of the zonal current system contribute to the eddy production rates and thus to the generation of TIWs in the central tropical Atlantic Ocean. In the Southern Hemisphere, TIWs are forced only by baroclinic instability associated with the vertical shear of the central part of the South Equatorial Current (SEC). In the Northern Hemisphere, baroclinic instability due to the vertical shear of the northern SEC... |
| Tipo: Text |
Palavras-chave: Barotropic and baroclinic instability; Tropical Atlantic; Tropical instability waves. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4554.pdf |
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