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| Pellichero, Violaine; Sallee, Jean-baptiste; Schmidtko, Sunke; Roquet, Fabien; Charrassin, Jean-benoit. |
| The oceanic mixed layer is the gateway for the exchanges between the atmosphere and the ocean; in this layer, all hydrographic ocean properties are set for months to millennia. A vast area of the Southern Ocean is seasonally capped by sea-ice, which alters the characteristics of the ocean mixed layer. The interaction between the ocean mixed layer and sea-ice plays a key role for water mass transformation, the carbon cycle, sea-ice dynamics, and ultimately for the climate as a whole. However, the structure and characteristics of the under-ice mixed layer are poorly understood due to the sparseness of in situ observations and measurements. In this study, we combine distinct sources of observations to overcome this lack in our understanding of the polar... |
| Tipo: Text |
Palavras-chave: Southern Ocean; Mixed layer; Sea-ice; Elephant seals; Salt budget; Heat budget. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00383/49400/49901.pdf |
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| Charrassin, J. -b.; Hindell, M.; Rintoul, S. R.; Roquet, Fabien; Sokolov, S.; Biuw, M.; Costa, D.; Boehme, L.; Lovell, P.; Coleman, R.; Timmermann, R.; Meijers, A.; Meredith, M.; Park, Y. -h.; Bailleul, F.; Goebel, M.; Tremblay, Y; Bost, C. -a.; Mcmahon, C. R.; Field, I. C.; Fedak, M. A.; Guinet, C. |
| Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals (Mirounga leonina) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice... |
| Tipo: Text |
Palavras-chave: Antarctic circumpolar current; Instrumentation; Marine predators; Ocean observation; Sea-ice modeling. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00241/35239/33750.pdf |
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| Boehme, L.; Lovell, P.; Biuw, M.; Roquet, Fabien; Nicholson, J.; Thorpe, S. E.; Meredith, M. P.; Fedak, M.. |
| The increasing need for continuous monitoring of the world oceans has stimulated the development of a range of autonomous sampling platforms. One novel addition to these approaches is a small, relatively inexpensive data-relaying device that can be deployed on marine mammals to provide vertical oceanographic profiles throughout the upper 2000 m of the water column. When an animal dives, the CTD-Satellite Relay Data Logger (CTD-SRDL) records vertical profiles of temperature, conductivity and pressure. Data are compressed once the animal returns to the surface where it is located by, and relays data to, the Argos satellite system. The technical challenges met in the design of the CTD-SRDL are the maximising of energy efficiency and minimising size, whilst... |
| Tipo: Text |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00241/35237/33748.pdf |
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| Mensah, Vigan; Roquet, Fabien; Siegelman-charbit, Lia; Picard, Baptiste; Pauthenet, Etienne; Guinet, Christophe. |
| The effect of thermal mass on the salinity estimate from conductivity-temperature-depth (CTD) tags sensor mounted on marine mammals is documented, and a correction scheme is proposed to mitigate its impact. The algorithm developed here allows for a direct correction of the salinity data, rather than a correction of the sample's conductivity and temperature. The amplitude of the thermal mass-induced error on salinity and its correction are evaluated via comparison between data from CTD tags and from Sea-Bird Scientific CTD used as a reference. Thermal mass error on salinity appears to be generally O(10(-2)) g kg(-1), it may reach O(10(-1)) g kg(-1), and it tends to increase together with the magnitude of the cumulated temperature gradient (T-HP) within the... |
| Tipo: Text |
Palavras-chave: Data processing; In situ oceanic observations; Instrumentation; Sensors; Profilers; Oceanic. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00585/69697/67577.pdf |
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| Roquet, Fabien; Wunsch, Carl; Forget, Gael; Heimbach, Patrick; Guinet, Christophe; Reverdin, Gilles; Charrassin, Jean-benoit; Bailleul, Frederic; Costa, Daniel P.; Huckstadt, Luis A.; Goetz, Kimberly T.; Kovacs, Kit M.; Lydersen, Christian; Biuw, Martin; Nost, Ole A.; Bornemann, Horst; Ploetz, Joachim; Bester, Marthan N.; Mcintyre, Trevor; Muelbert, Monica C.; Hindell, Mark A.; Mcmahon, Clive R.; Williams, Guy; Harcourt, Robert; Field, Iain C.; Chafik, Leon; Nicholls, Keith W.; Boehme, Lars; Fedak, Mike A.. |
| Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea... |
| Tipo: Text |
Palavras-chave: Animal-borne sampling; Southern Ocean; State estimation; Hydrography. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00241/35252/33765.pdf |
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| Siegelman, Lia; Roquet, Fabien; Mensah, Vigan; Riviere, Pascal; Pauthenet, Etienne; Picard, Baptiste; Guinet, Christophe. |
| Most available CTD Satellite Relay Data Logger (CTD-SRDL) profiles are heavily compressed before satellite transmission. High-resolution profiles recorded at the sampling frequency of 0.5 Hz are, however, available upon physical retrieval of the logger. Between 2014 and 2018, several loggers deployed on elephant seals in the Southern Ocean have been set in continuous recording mode, capturing both the ascent and descent for over 60 profiles per day during several months, opening new horizons for the physical oceanography community. Taking advantage of a new dataset made of seven such loggers, a postprocessing procedure is proposed and validated to improve the quality of all CTD-SRDL data: that is, both high-resolution profiles and compressed low-resolution... |
| Tipo: Text |
Palavras-chave: Algorithms; Data processing; In situ oceanic observations. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00494/60567/64043.pdf |
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| Gaillard, Fabienne; Reynaud, Thierry; Von Schuckmann, Karina; Roquet, Fabien; Prigent, Annaig; Lagadec, Catherine. |
| The Argo array, by offering simultaneously global coverage and high vertical resolution, made the monitoring of inter-annual and decadal variability of the ocean interior possible. In the ARIVO project, we have initiated the production of gridded monthly fields of temperature and salinity using an optimal analysis tool and designed an iterative approach to combine near-real time and delayed mode data. The monthly gridded fields are averaged over time to produce the reference state needed by climatological studies, dynamical modeling and reconstruction methods themselves. Higher degree statistics such as variances and extreme values are later derived. Global indices (heat content, dynamical height) and corresponding error bars are also computed. Sensitivity... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00112/22355/20035.pdf |
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