Mass, nutrients and dissolved organic carbon (DOC) lateral transports off northwest Africa during fall 2002 and spring 2003
<p>The circulation patterns and the impact of the lateral export of nutrients and organic matter off NW Africa are examined by applying an inverse model to two hydrographic datasets gathered in fall 2002 and spring 2003. These estimates show significant changes in the circulation patterns at c...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-04-01
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| Series: | Ocean Science |
| Online Access: | https://www.ocean-sci.net/16/483/2020/os-16-483-2020.pdf |
| Summary: | <p>The circulation patterns and the impact of the lateral export of nutrients and organic matter off NW Africa are examined by applying an inverse model to two hydrographic datasets gathered in fall 2002 and spring 2003. These estimates show significant changes in the circulation patterns at central levels from fall to spring, particularly in the southern boundary of the domain related to zonal shifts of the Cape Verde Frontal Zone. Southward transports at the surface and central levels at 26<span class="inline-formula"><sup>∘</sup></span> N are <span class="inline-formula">5.6±1.9</span> Sv in fall and increase to <span class="inline-formula">6.7±1.6</span> Sv in spring; westward transports at 26<span class="inline-formula"><sup>∘</sup></span> W are <span class="inline-formula">6.0±1.8</span> Sv in fall and weaken to <span class="inline-formula">4.0±1.8</span> Sv in spring. At 21<span class="inline-formula"><sup>∘</sup></span> N a remarkable temporal variability is obtained, with a northward mass transport of <span class="inline-formula">4.4±1.5</span> Sv in fall and a southward transport of <span class="inline-formula">5.2±1.6</span> Sv in spring. At intermediate levels important spatiotemporal differences are also observed, and it must be highlighted that a northward net mass transport of <span class="inline-formula">2.0±1.9</span> Sv is obtained in fall at both the south and north transects. The variability in the circulation patterns is also reflected in lateral transports of inorganic nutrients (<span class="inline-formula">SiO<sub>2</sub></span>, <span class="inline-formula">NO<sub>3</sub></span>, <span class="inline-formula">PO<sub>4</sub></span>) and dissolved organic carbon (<span class="inline-formula">DOC</span>). Hence, in fall the area acts as a sink of inorganic nutrients and a source of <span class="inline-formula">DOC</span>, while in spring it reverses to a source of inorganic nutrients and a sink of <span class="inline-formula">DOC</span>. A comparison between nutrient fluxes from both in situ observations and numerical modeling output is finally addressed.</p> |
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| ISSN: | 1812-0784 1812-0792 |