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| Wilson, Cara; Speer, Kevin; Charlou, Jean-luc; Bougault, Henri; Klinkhammer, Gary. |
| As part of the French-American Ridge Atlantic program the French-American Zero-Angle Photon Spectrometer and Rocks (FAZAR) cruise conducted water column studies between 33 and 40 degrees N along the Mid-Atlantic Ridge (MAR)) to detect hydrothermal activity and map its influence, This paper describes the large-scale hydrography within the axial valley, with particular emphasis on the hydrothermally active Lucky Strike segment (37 degrees 17'N). The FAZAR study area is affected be the presence of the Azores Current and Mediterranean Water (MW). Although the MW core has been mapped as far north as 50 degrees N off the ridge; the northern boundary Of the MW within the MAR in the FAZAR study area exists as a strong front south of the Azores platform. This front... |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00069/18038/15586.pdf |
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| Russell, Joellen L.; Kamenkovich, Igor; Bitz, Cecilia; Ferrari, Raffaele; Gille, Sarah T.; Goodman, Paul J.; Hallberg, Robert; Johnson, Kenneth; Khazmutdinova, Karina; Marinov, Irina; Mazloff, Matthew; Riser, Stephen; Sarmiento, Jorge L.; Speer, Kevin; Talley, Lynne D.; Wanninkhof, Rik. |
| The Southern Ocean is central to the global climate and the global carbon cycle, and to the climate's response to increasing levels of atmospheric greenhouse gases, as it ventilates a large fraction of the global ocean volume. Global coupled climate models and earth system models, however, vary widely in their simulations of the Southern Ocean and its role in, and response to, the ongoing anthropogenic trend. Due to the region's complex water-mass structure and dynamics, Southern Ocean carbon and heat uptake depend on a combination of winds, eddies, mixing, buoyancy fluxes, and topography. Observationally based metrics are critical for discerning processes and mechanisms, and for validating and comparing climate and earth system models. New observations... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Heat uptake; Carbon uptake; Observationally based metrics. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00673/78491/80788.pdf |
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| Sallee, Jean-baptiste; Speer, Kevin; Rintoul, Steve; Wijffels, S.. |
| An approximate mass (volume) budget in the surface layer of the Southern Ocean is used to investigate the intensity and regional variability of the ventilation process, discussed here in terms of subduction and up-welling. Ventilation resulting from Ekman pumping is estimated from satellite winds, the geostrophic mean component is assessed from a climatology strengthened with Argo data, and the eddy-induced advection is included via the parameterization of Gent and McWilliams, together with eddy mixing estimates. All three components contribute significantly to ventilation. Finally, the seasonal cycle of the upper ocean is resolved using Argo data. The circumpolar-averaged circulation shows an upwelling in the Antarctic Intermediate Water (AAIW) density... |
| Tipo: Text |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00483/59419/62217.pdf |
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| Emanuel, Kerry A; Speer, Kevin; Rotunno, Richard; Srivastava, Ramesh; Molina, Mario. |
| Bolide impacts and large-scale volcanic eruptions have been proposed as possible causes of the massive extinction of life that has occurred episodically in Earth's history. In spite of the catastrophic disruption of the local environment that accompanies bolide impacts and volcanic eruptions, it has been difficult to explain why these events sometimes lead to global extinction of species. We propose that, in some cases, the missing link may be provided by hypercanes, runaway hurricanes that are capable of injecting massive amounts of water and aerosols into the middle and upper stratosphere, where they may have profound effects on atmospheric chemistry and radiative transfer. Hypercanes are theorized to occur when the sea surface temperature exceeds a... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00258/36966/35611.pdf |
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| Rintoul, Stephen R; Sparrow, Mike; Meredith, Michael P; Wadley, Victoria; Speer, Kevin; Hofmann, Eileen; Summerhayes, Colin; Urban, Ed; Bellerby, Richard. |
| The Southern Ocean provides the principal connection between the Earth’s ocean basins and between the upper and lower layers of the global ocean circulation. As a result, the Southern Ocean strongly influences climate patterns and the cycling of carbon and nutrients. Changes in the Southern Ocean therefore have global ramifications. Limited observations suggest the Southern Ocean is indeed changing: the region is warming more rapidly than the global ocean average; salinity changes driven by changes in precipitation and ice melt have been observed in both the upper and abyssal ocean; the uptake of carbon by the Southern Ocean has slowed the rate of atmospheric climate change but caused basin-wide ocean acidification; and Southern Ocean ecosystems are... |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00651/76345/77335.pdf |
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| Mullineaux, Lauren; Speer, Kevin; Thurnherr, Andreas; Maltrud, Matthew; Vangriesheim, Annick. |
| Introduction : Dispersal processes play an important role in the structure and dynamics of many terrestrial and marine communities, and they are especially critical in deep-sea hydrothermal vent ecosystems. These systems are patchy and transient, and most of the species inhabiting them cannot survive elsewhere, so successful dispersal (usually via a larval stage) is essential for maintaining viable populations and species ranges. To understand the mechanisms of larval dispersal, we need to know larval life spans and the transport dynamics of deep-water flows near vent habitats. When these values are measured for a species in a given region, a maximum dispersal distance can be calculated and compared to the geographic spacing between vent fields in that... |
| Tipo: Text |
Palavras-chave: Numerical models; Dipersal potential; Larvae; Flow regime; Hydrothermal vent; Deep sea ecosystems. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-898.pdf |
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| Ferron, Bruno; Mercier, Herle; Speer, Kevin; Gargett, Ann; Polzin, Kurt. |
| The Romanche Fracture Zone is a major gap in the Mid-Atlantic Ridge at the equator, which is deep enough to allow significant eastward flows of Antarctic Bottom Water from the Brazil Basin to the Sierra Leone and Guinea Abyssal Plains. While flowing through the Romanche Fracture Zone, bottom-water properties are strongly modified due to intense vertical mixing. The diapycnal mixing coefficient in the bottom water of the Romanche Fracture Zone is estimated by using the finestructure of CTD profiles, the microstructure of high-resolution profiler data, and by constructing a heat budget from current meter data. The finestructure of density profiles is described using the Thorpe scales L-T. It is shown from microstructure data taken in the bottom water that... |
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| Ano: 1998 |
URL: https://archimer.ifremer.fr/doc/00447/55830/62131.pdf |
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