Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation

<p>A kilometre-scale coupled ocean–atmosphere numerical simulation is used to study the impact of the 7 November 2014 medicane on the oceanic upper layer. The processes at play are elucidated through analyses of the tendency terms for temperature and salinity in the oceanic mixed layer. While...

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Main Authors: M.-N. Bouin, C. Lebeaupin Brossier
Format: Article
Language:English
Published: Copernicus Publications 2020-09-01
Series:Ocean Science
Online Access:https://os.copernicus.org/articles/16/1125/2020/os-16-1125-2020.pdf
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author M.-N. Bouin
M.-N. Bouin
C. Lebeaupin Brossier
author_facet M.-N. Bouin
M.-N. Bouin
C. Lebeaupin Brossier
author_sort M.-N. Bouin
collection DOAJ
description <p>A kilometre-scale coupled ocean–atmosphere numerical simulation is used to study the impact of the 7 November 2014 medicane on the oceanic upper layer. The processes at play are elucidated through analyses of the tendency terms for temperature and salinity in the oceanic mixed layer. While comparable by its maximum wind speed to a Category 1 tropical cyclone, the medicane results in a substantially weaker cooling. As in weak to moderate tropical cyclones, the dominant contribution to the surface cooling is the surface heat fluxes with secondary effects from the turbulent mixing and lateral advection. Upper-layer salinity decreases due to heavy precipitation that overcompensates the salinizing effect of evaporation and turbulent mixing. The upper-layer evolution is marked by several features believed to be typical of Mediterranean cyclones. First, strong, convective rain occurring at the beginning of the event builds a marked salinity barrier layer. As a consequence, the action of surface forcing is favoured and the turbulent mixing dampened with a net increase in the surface cooling as a result. Second, due to colder surface temperature and weaker stratification, a cyclonic eddy is marked by a weaker cooling opposite to what is usually observed in tropical cyclones. Third, the strong dynamics of the Strait of Sicily enhance the role of the lateral advection in the cooling and warming processes of the mixed layer.</p>
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spelling doaj.art-4b4451d30a8349669b526faaa987ab6b2022-12-21T17:50:31ZengCopernicus PublicationsOcean Science1812-07841812-07922020-09-01161125114210.5194/os-16-1125-2020Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulationM.-N. Bouin0M.-N. Bouin1C. Lebeaupin Brossier2CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, FranceUniv. Brest, CNRS, IRD, Ifremer, Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM, 29840 Brest, FranceCNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France<p>A kilometre-scale coupled ocean–atmosphere numerical simulation is used to study the impact of the 7 November 2014 medicane on the oceanic upper layer. The processes at play are elucidated through analyses of the tendency terms for temperature and salinity in the oceanic mixed layer. While comparable by its maximum wind speed to a Category 1 tropical cyclone, the medicane results in a substantially weaker cooling. As in weak to moderate tropical cyclones, the dominant contribution to the surface cooling is the surface heat fluxes with secondary effects from the turbulent mixing and lateral advection. Upper-layer salinity decreases due to heavy precipitation that overcompensates the salinizing effect of evaporation and turbulent mixing. The upper-layer evolution is marked by several features believed to be typical of Mediterranean cyclones. First, strong, convective rain occurring at the beginning of the event builds a marked salinity barrier layer. As a consequence, the action of surface forcing is favoured and the turbulent mixing dampened with a net increase in the surface cooling as a result. Second, due to colder surface temperature and weaker stratification, a cyclonic eddy is marked by a weaker cooling opposite to what is usually observed in tropical cyclones. Third, the strong dynamics of the Strait of Sicily enhance the role of the lateral advection in the cooling and warming processes of the mixed layer.</p>https://os.copernicus.org/articles/16/1125/2020/os-16-1125-2020.pdf
spellingShingle M.-N. Bouin
M.-N. Bouin
C. Lebeaupin Brossier
Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
Ocean Science
title Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
title_full Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
title_fullStr Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
title_full_unstemmed Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
title_short Impact of a medicane on the oceanic surface layer from a coupled, kilometre-scale simulation
title_sort impact of a medicane on the oceanic surface layer from a coupled kilometre scale simulation
url https://os.copernicus.org/articles/16/1125/2020/os-16-1125-2020.pdf
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