Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT
<p>We investigate ocean dynamics at different scales in the Agulhas Current system, a region of important interocean exchange of heat and energy. While ocean observations and some of the most advanced climate models capture the larger mesoscale dynamics (<span class="inline-formula&quo...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-10-01
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| Series: | Ocean Science |
| Online Access: | https://os.copernicus.org/articles/19/1413/2023/os-19-1413-2023.pdf |
| _version_ | 1797665292152733696 |
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| author | E. Carli R. Morrow O. Vergara R. Chevrier L. Renault |
| author_facet | E. Carli R. Morrow O. Vergara R. Chevrier L. Renault |
| author_sort | E. Carli |
| collection | DOAJ |
| description | <p>We investigate ocean dynamics at different scales in the Agulhas Current system, a region of important interocean exchange of heat and energy. While ocean observations and some of the most advanced climate models capture the larger mesoscale dynamics (<span class="inline-formula">></span> 100 km), the smaller-scale fronts and eddies are underrepresented. The recently launched NASA–CNES Surface Water and Ocean Topography (SWOT) wide-swath altimeter mission observes the smaller ocean geostrophic scales down to 15 km in wavelength globally. Here we will analyse different eddy diagnostics in the Agulhas Current region and quantify the contributions from the larger mesoscales observable today and the smaller scales to be observed with SWOT. Surface geostrophic diagnostics of eddy kinetic energy, strain, and energy cascades are estimated from modelled sea surface height (SSH) fields of the Massachusetts Institute of Technology general circulation model (MITgcm) latitude–longitude polar cap (LLC4320) simulation subsampled at 1/10<span class="inline-formula"><sup>∘</sup></span>. In this region, the smaller scales (<span class="inline-formula"><150</span> km) have a strong signature on the horizontal geostrophic strain rate and for all eddy diagnostics in the Western Boundary Current and along the meandering Agulhas Extension. We investigate the horizontal cascade of energy using a coarse-graining technique, and we observe that the wavelength range where the inverse cascade occurs is biased towards larger mesoscale wavelengths with today’s altimetric sampling. We also calculate the projected sampling of the eddy diagnostics under the SWOT swaths built with the NASA–CNES simulator to include the satellite position and realistic noise. For the swaths, a neural network noise mitigation method is implemented to reduce the residual SWOT random error before calculating eddy diagnostics. In terms of SSH, observable wavelengths of 15 to 20 km are retrieved after neural network noise mitigation, as opposed to wavelengths larger than 40 km before the noise reduction.</p> |
| first_indexed | 2024-03-11T19:42:50Z |
| format | Article |
| id | doaj.art-c33c6d3606c8476a933f868ed7c70890 |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-03-11T19:42:50Z |
| publishDate | 2023-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-c33c6d3606c8476a933f868ed7c708902023-10-06T08:00:16ZengCopernicus PublicationsOcean Science1812-07841812-07922023-10-01191413143510.5194/os-19-1413-2023Ocean 2D eddy energy fluxes from small mesoscale processes with SWOTE. Carli0R. Morrow1O. Vergara2R. Chevrier3L. Renault4Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (CNES-CNRS-IRD-UPS), Toulouse, FranceLaboratoire d'Etudes en Géophysique et Océanographie Spatiales (CNES-CNRS-IRD-UPS), Toulouse, FranceCollecte Localisation Satellites (CLS), Toulouse, FranceCollecte Localisation Satellites (CLS), Toulouse, FranceLaboratoire d'Etudes en Géophysique et Océanographie Spatiales (CNES-CNRS-IRD-UPS), Toulouse, France<p>We investigate ocean dynamics at different scales in the Agulhas Current system, a region of important interocean exchange of heat and energy. While ocean observations and some of the most advanced climate models capture the larger mesoscale dynamics (<span class="inline-formula">></span> 100 km), the smaller-scale fronts and eddies are underrepresented. The recently launched NASA–CNES Surface Water and Ocean Topography (SWOT) wide-swath altimeter mission observes the smaller ocean geostrophic scales down to 15 km in wavelength globally. Here we will analyse different eddy diagnostics in the Agulhas Current region and quantify the contributions from the larger mesoscales observable today and the smaller scales to be observed with SWOT. Surface geostrophic diagnostics of eddy kinetic energy, strain, and energy cascades are estimated from modelled sea surface height (SSH) fields of the Massachusetts Institute of Technology general circulation model (MITgcm) latitude–longitude polar cap (LLC4320) simulation subsampled at 1/10<span class="inline-formula"><sup>∘</sup></span>. In this region, the smaller scales (<span class="inline-formula"><150</span> km) have a strong signature on the horizontal geostrophic strain rate and for all eddy diagnostics in the Western Boundary Current and along the meandering Agulhas Extension. We investigate the horizontal cascade of energy using a coarse-graining technique, and we observe that the wavelength range where the inverse cascade occurs is biased towards larger mesoscale wavelengths with today’s altimetric sampling. We also calculate the projected sampling of the eddy diagnostics under the SWOT swaths built with the NASA–CNES simulator to include the satellite position and realistic noise. For the swaths, a neural network noise mitigation method is implemented to reduce the residual SWOT random error before calculating eddy diagnostics. In terms of SSH, observable wavelengths of 15 to 20 km are retrieved after neural network noise mitigation, as opposed to wavelengths larger than 40 km before the noise reduction.</p>https://os.copernicus.org/articles/19/1413/2023/os-19-1413-2023.pdf |
| spellingShingle | E. Carli R. Morrow O. Vergara R. Chevrier L. Renault Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT Ocean Science |
| title | Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT |
| title_full | Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT |
| title_fullStr | Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT |
| title_full_unstemmed | Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT |
| title_short | Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT |
| title_sort | ocean 2d eddy energy fluxes from small mesoscale processes with swot |
| url | https://os.copernicus.org/articles/19/1413/2023/os-19-1413-2023.pdf |
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