




Yu, Xiaolong; Naveira Garabato, Alberto C.; Martin, Adrian P; Buckingham, Christian; Brannigan, Liam; Su, Zhan. 
Numerical simulations suggest that submesoscale turbulence may transform lateral buoyancy gradients into vertical stratification, and thus restratify the upper ocean via vertical flow. However, the observational evidence for this restratifying process has been lacking due to the difficulty in measuring such ephemeral phenomena, particularly over periods of months to years. This study presents an annual cycle of the vertical velocity and associated restratification estimated from two nested clusters of meso and submesoscaleresolving moorings, deployed in a typical midocean area of the Northeast Atlantic. Vertical velocities inferred using the nondiffusive density equation are substantially stronger at submesoscales (horizontal scales of 110 km) than at... 
Tipo: Text 
Palavraschave: Ocean; Atlantic Ocean; Ageostrophic circulations; Frontogenesis; Frontolysis; In situ oceanic observations. 
Ano: 2019 
URL: https://archimer.ifremer.fr/doc/00489/60076/63398.pdf 
 

 


Gommenginger, Christine; Chapron, Bertrand; Hogg, Andy; Buckingham, Christian; Foxkemper, Baylor; Eriksson, Leif; Soulat, Francois; Ubelmann, Clément; Ocampotorres, Francisco; Nardelli, Bruno Buongiorno; Griffin, David; Lopezdekker, Paco; Knudsen, Per; Andersen, Ole; Stenseng, Lars; Stapleton, Neil; Perrie, William; Violantecarvalho, Nelson; Schulzstellenfleth, Johannes; Woolf, David; Isernfontanet, Jordi; Ardhuin, Fabrice; Klein, Patrice; Mouche, Alexis; Pascual, Ananda; Capet, Xavier; Hauser, Daniele; Stoffelen, Ad; Morrow, Rosemary; Aouf, Lotfi; Breivik, Øyvind; Fu, Leelueng; Johannessen, Johnny A.; Aksenov, Yevgeny; Bricheno, Lucy; Hirschi, Joel; Martin, Adrien Ch; Martin, Adiran P; Nurser, George; Polton, Jeff; Wolf, Judith; Johnsen, Harald; Soloviev, Alexander; Jacobs, Gregg A.; Collard, Fabrice; Groom, Steve; Kudryavtsev, Vladimir; Wilkin, John; Navarro, Victor; Babanin, Alex; Martin, Matthew; Siddorn, John; Saulter, Andrew; Rippeth, Tom; Emery, Bill; Maximenko, Nikolai; Romeiser, Roland; Graber, Hans; Azcarate, Aida Alvera; Hughes, Chris W.; Vandemark, Doug; Silva, Jose Da; Leeuwen, Peter Jan Van; Naveiragarabato, Alberto; Gemmrich, Johannes; Mahadevan, Amala; Marquez, Jose; Munro, Yvonne; Doody, Sam; Burbidge, Geoff. 
Highresolution satellite images of ocean color and sea surface temperature reveal an abundance of ocean fronts, vortices and filaments at scales below 10 km but measurements of ocean surface dynamics at these scales are rare. There is increasing recognition of the role played by small scale ocean processes in oceanatmosphere coupling, upperocean mixing and ocean vertical transports, with advanced numerical models and in situ observations highlighting fundamental changes in dynamics when scales reach 1 km. Numerous scientific publications highlight the global impact of small oceanic scales on marine ecosystems, operational forecasts and longterm climate projections through strong ageostrophic circulations, large vertical ocean velocities and mixed layer... 
Tipo: Text 
Palavraschave: Satellite; Air sea interactions; Upper ocean dynamics; Submesoscale; Coastal; Marginal ice zone; Radar; Alongtrack interferometry. 
Ano: 2019 
URL: https://archimer.ifremer.fr/doc/00510/62121/66325.pdf 
 


Buckingham, Christian; Gula, Jonathan; Carton, Xavier. 
In this study, we examine the role of curvature in modifying frontal stability. We first evaluate the classical criterion that the Coriolis parameter f multiplied by the Ertel potential vorticity (PV) q is positive for stable flow and that instability is possible when this quantity is negative. The first portion of this statement can be deduced from Ertel’s PV theorem, assuming an initially positive fq. Moreover, the full statement is implicit in the governing equation for the mean geostrophic flow, as the discriminant, fq, changes sign. However, for curved fronts in cyclogeostrophic or gradient wind balance (GWB), an additional term enters the discriminant owing to conservation of absolute angular momentum L. The resulting expression, (1 + Cu)fq < 0 or... 
Tipo: Text 
Palavraschave: Instability; Ocean dynamics; Potential vorticity; Turbulence; Frontogenesis/frontolysis; Fronts; Vortices; Angular momentum. 
Ano: 2021 
URL: https://archimer.ifremer.fr/doc/00677/78920/81288.pdf 
 


Buckingham, Christian; Gula, Jonathan; Carton, Xavier. 
We continue our study of the role of curvature in modifying frontal stability. In Part I, we obtained an instability criterion valid for curved fronts and vortices in gradient wind balance (GWB): Φ′ = L′q′ < 0, where L′ and q′ are the nondimensional absolute angular momentum and Ertel potential vorticity (PV), respectively. In Part II, we investigate this criterion in a parameter space representative of lowRichardsonnumber fronts and vortices in GWB. An interesting outcome is that, for Richardson numbers near 1, anticyclonic flows increase in q′, while cyclonic flows decrease in q′, tending to stabilize anticyclonic and destabilize cyclonic flow. Although stability is marginal or weak for anticyclonic flow (owing to multiplication by L′), the... 
Tipo: Text 
Palavraschave: Eddies; Fronts; Instability; Ocean circulation; Potential vorticity; Frontogenesis/frontolysis; Vortices; Angular momentum. 
Ano: 2021 
URL: https://archimer.ifremer.fr/doc/00677/78919/81286.pdf 
 


