Articles | Volume 11, issue 2
https://doi.org/10.5194/gi-11-359-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gi-11-359-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
25 Oct 2022
Research article |
| 25 Oct 2022
| 25 Oct 2022
Glider observations of thermohaline staircases in the tropical North Atlantic using an automated classifier
Callum Rollo
CORRESPONDING AUTHOR
Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
Karen J. Heywood
Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
Rob A. Hall
Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
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Meredith G. Meyer, Robert J. W. Brewin, Xuerong Sun, Clara Manno, Florence Atherden, Sasha J. Kramer, Giorgio Dall'Olmo, and Karen J. Heywood
EGUsphere, https://doi.org/10.5194/egusphere-2026-3148, https://doi.org/10.5194/egusphere-2026-3148, 2026
This preprint is open for discussion and under review for Ocean Science (OS).
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Antarctica is a key region for carbon cycling and export. The efficiency of carbon export has been linked to the type of phytoplankton dominating the system. Our results suggest diatoms, haptophytes, and cryptophytes are present in all water column samples despite substantial physical differences between sampling locations. Our data shows a strong relationship between the proportion of diatoms, haptophytes, and cryptophytes relative to all other phytoplankton and the magnitude of carbon flux.
Tom A. Jordan, Karen J. Heywood, Anna Wåhlin, Rob A. Hall, Atsuhiro Muto, Pierre Dutrieux, Kelly Hogan, James Girton, Karen E. Alley, and Erin Pettit
EGUsphere, https://doi.org/10.5194/egusphere-2025-6001, https://doi.org/10.5194/egusphere-2025-6001, 2026
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The shape of the water filled cavity hidden beneath ice shelves is extremely important, but hard to measure. Gravity data collected from aircraft can be used to predict the shape. However, in the Dotson Crosson ice shelves in West Antarctica, new direct observations from autonomous platforms sent beneath the ice, and seismic observations from the ice surface showed gravity models were systematically too shallow. We explain why and provide a solution applicable her and in other ice shelves.
Gerd A. Bruss, Estel Font, Bastien Y. Queste, and Rob A. Hall
Ocean Sci., 22, 31–47, https://doi.org/10.5194/os-22-31-2026, https://doi.org/10.5194/os-22-31-2026, 2026
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We studied internal tides in the Gulf of Oman, where they had not been observed in detail before. Using seabed instruments, we found that these underwater waves travel far inshore, strengthen as the season shifts toward fall, and stay predictable for weeks. They may bring cooler, low-oxygen water to coastal areas, influencing marine ecosystems and reef health.
Maren Elisabeth Richter, Karen J. Heywood, Rob A. Hall, and Peter E. D. Davis
Ocean Sci., 21, 3341–3359, https://doi.org/10.5194/os-21-3341-2025, https://doi.org/10.5194/os-21-3341-2025, 2025
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Warm ocean water causes rapid melting of Antarctic glaciers. The circulation and mixing of warm water in ice shelf cavities is mostly unknown. We observed ocean currents and mixing under Dotson Ice Shelf. Mixing is low, with patches of higher mixing associated with stronger currents and vertical current shear. The levels of turbulent mixing will lead to negligible heat loss during the path of the warm water to the grounding line, leaving plenty of heat available to melt the ice shelf there.
Daisy D. Pickup, Dorothee C. E. Bakker, Karen J. Heywood, Francis Glassup, Emily M. Hammermeister, Sharon E. Stammerjohn, Gareth A. Lee, Socratis Loucaides, Bastien Y. Queste, Benjamin G. M. Webber, and Patricia L. Yager
Ocean Sci., 21, 2727–2741, https://doi.org/10.5194/os-21-2727-2025, https://doi.org/10.5194/os-21-2727-2025, 2025
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Autonomous platforms in the Amundsen Sea have allowed for detection of isolated water masses that are colder, saltier and denser than overlying water. They are also associated with a higher dissolved inorganic carbon concentration and lower pH. The water masses, referred to as lenses, could have implications for the transfer of heat and storage of carbon in the region. We hypothesise that they form in surrounding areas that experience intense cooling and sea ice formation in autumn/winter.
Christian T. Wild, Tasha Snow, Tiago S. Dotto, Peter E. D. Davis, Scott Tyler, Ted A. Scambos, Erin C. Pettit, and Karen J. Heywood
Ocean Sci., 21, 2605–2629, https://doi.org/10.5194/os-21-2605-2025, https://doi.org/10.5194/os-21-2605-2025, 2025
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Thwaites Glacier is retreating due to warm ocean water melting it from below, but its thick ice shelf makes this heat hard to monitor. Using hot-water drilling, we placed sensors beneath the floating ice, revealing how surface freezing in Pine Island Bay influences heat at depth. Alongside gradual warming, we found bursts of heat that could speed up melting at the grounding zone, which may become more common as sea ice declines.
Shenjie Zhou, Pierre Dutrieux, Claudia F. Giulivi, Adrian Jenkins, Alessandro Silvano, Christopher Auckland, E. Povl Abrahamsen, Michael Meredith, Irena Vaňková, Keith Nicholls, Peter E. D. Davis, Svein Østerhus, Arnold L. Gordon, Christopher J. Zappa, Tiago S. Dotto, Ted Scambos, Kathryn L. Gunn, Stephen R. Rintoul, Shigeru Aoki, Craig Stevens, Chengyan Liu, Sukyoung Yun, Tae-Wan Kim, Won Sang Lee, Markus Janout, Tore Hattermann, Julius Lauber, Elin Darelius, Anna Wåhlin, Leo Middleton, Pasquale Castagno, Giorgio Budillon, Karen J. Heywood, Jennifer Graham, Stephen Dye, Daisuke Hirano, and Una Kim Miller
Earth Syst. Sci. Data, 17, 5693–5706, https://doi.org/10.5194/essd-17-5693-2025, https://doi.org/10.5194/essd-17-5693-2025, 2025
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We created the first standardised dataset of in-situ ocean measurements time series from around Antarctica collected since 1970s. This includes temperature, salinity, pressure, and currents recorded by instruments deployed in icy, challenging conditions. Our analysis highlights the dominance of tidal currents and separates these from other patterns to study regional energy distribution. This unique dataset offers a foundation for future research on Antarctic ocean dynamics and ice interactions.
Meredith G. Meyer, Esther Portela, Walker O. Smith Jr., and Karen J. Heywood
Ocean Sci., 21, 1223–1236, https://doi.org/10.5194/os-21-1223-2025, https://doi.org/10.5194/os-21-1223-2025, 2025
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During the annual phytoplankton bloom, rates of primary production and carbon export in the Ross Sea, Antarctica, are uncoupled from each other and from oxygen and carbon stocks. These biogeochemical rates support the high-productivity, low-export classification of the region and suggest that environmental factors influence these stocks and rates differently and make projections under future climate change scenarios difficult.
Ria Oelerich, Karen J. Heywood, Gillian M. Damerell, Marcel du Plessis, Louise C. Biddle, and Sebastiaan Swart
Ocean Sci., 19, 1465–1482, https://doi.org/10.5194/os-19-1465-2023, https://doi.org/10.5194/os-19-1465-2023, 2023
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At the southern boundary of the Antarctic Circumpolar Current, relatively warm waters encounter the colder waters surrounding Antarctica. Observations from underwater vehicles and altimetry show that medium-sized cold-core eddies influence the southern boundary's barrier properties by strengthening the slopes of constant density lines across it and amplifying its associated jet. As a result, the ability of exchanging properties, such as heat, across the southern boundary is reduced.
Pierre L'Hégaret, Florian Schütte, Sabrina Speich, Gilles Reverdin, Dariusz B. Baranowski, Rena Czeschel, Tim Fischer, Gregory R. Foltz, Karen J. Heywood, Gerd Krahmann, Rémi Laxenaire, Caroline Le Bihan, Philippe Le Bot, Stéphane Leizour, Callum Rollo, Michael Schlundt, Elizabeth Siddle, Corentin Subirade, Dongxiao Zhang, and Johannes Karstensen
Earth Syst. Sci. Data, 15, 1801–1830, https://doi.org/10.5194/essd-15-1801-2023, https://doi.org/10.5194/essd-15-1801-2023, 2023
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In early 2020, the EUREC4A-OA/ATOMIC experiment took place in the northwestern Tropical Atlantic Ocean, a dynamical region where different water masses interact. Four oceanographic vessels and a fleet of autonomous devices were deployed to study the processes at play and sample the upper ocean, each with its own observing capability. The article first describes the data calibration and validation and second their cross-validation, using a hierarchy of instruments and estimating the uncertainty.
Manoj Joshi, Robert A. Hall, David P. Stevens, and Ed Hawkins
Earth Syst. Dynam., 14, 443–455, https://doi.org/10.5194/esd-14-443-2023, https://doi.org/10.5194/esd-14-443-2023, 2023
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The 18.6-year lunar nodal cycle arises from variations in the angle of the Moon's orbital plane and affects ocean tides. In this work we use a climate model to examine the effect of this cycle on the ocean, surface, and atmosphere. The timing of anomalies is consistent with the so-called slowdown in global warming and has implications for when global temperatures will exceed 1.5 ℃ above pre-industrial levels. Regional anomalies have implications for seasonal climate areas such as Europe.
Peter M. F. Sheehan, Gillian M. Damerell, Philip J. Leadbitter, Karen J. Heywood, and Rob A. Hall
Ocean Sci., 19, 77–92, https://doi.org/10.5194/os-19-77-2023, https://doi.org/10.5194/os-19-77-2023, 2023
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We calculate the rate of turbulent kinetic energy dissipation, i.e. the mixing driven by small-scale ocean turbulence, in the western tropical Atlantic Ocean via two methods. We find good agreement between the results of both. A region of elevated mixing is found between 200 and 500 m, and we calculate the associated heat and salt fluxes. We find that double-diffusive mixing in salt fingers, a common feature of the tropical oceans, drives larger heat and salt fluxes than the turbulent mixing.
Michael P. Hemming, Jan Kaiser, Jacqueline Boutin, Liliane Merlivat, Karen J. Heywood, Dorothee C. E. Bakker, Gareth A. Lee, Marcos Cobas García, David Antoine, and Kiminori Shitashima
Ocean Sci., 18, 1245–1262, https://doi.org/10.5194/os-18-1245-2022, https://doi.org/10.5194/os-18-1245-2022, 2022
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An underwater glider mission was carried out in spring 2016 near a mooring in the northwestern Mediterranean Sea. The glider deployment served as a test of a prototype ion-sensitive field-effect transistor pH sensor. Mean net community production rates were estimated from glider and buoy measurements of dissolved oxygen and inorganic carbon concentrations before and during the spring bloom. Incorporating advection is important for accurate mass budgets. Unexpected metabolic quotients were found.
Yixi Zheng, David P. Stevens, Karen J. Heywood, Benjamin G. M. Webber, and Bastien Y. Queste
The Cryosphere, 16, 3005–3019, https://doi.org/10.5194/tc-16-3005-2022, https://doi.org/10.5194/tc-16-3005-2022, 2022
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New observations reveal the Thwaites gyre in a habitually ice-covered region in the Amundsen Sea for the first time. This gyre rotates anticlockwise, despite the wind here favouring clockwise gyres like the Pine Island Bay gyre – the only other ocean gyre reported in the Amundsen Sea. We use an ocean model to suggest that sea ice alters the wind stress felt by the ocean and hence determines the gyre direction and strength. These processes may also be applied to other gyres in polar oceans.
Yanxin Wang, Karen J. Heywood, David P. Stevens, and Gillian M. Damerell
Ocean Sci., 18, 839–855, https://doi.org/10.5194/os-18-839-2022, https://doi.org/10.5194/os-18-839-2022, 2022
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It is important that climate models give accurate projections of future extremes in summer and winter sea surface temperature because these affect many features of the global climate system. Our results demonstrate that some models would give large errors if used for future projections of these features, and models with more detailed representation of vertical structure in the ocean tend to have a better representation of sea surface temperature, particularly in summer.
Bjorn Stevens, Sandrine Bony, David Farrell, Felix Ament, Alan Blyth, Christopher Fairall, Johannes Karstensen, Patricia K. Quinn, Sabrina Speich, Claudia Acquistapace, Franziska Aemisegger, Anna Lea Albright, Hugo Bellenger, Eberhard Bodenschatz, Kathy-Ann Caesar, Rebecca Chewitt-Lucas, Gijs de Boer, Julien Delanoë, Leif Denby, Florian Ewald, Benjamin Fildier, Marvin Forde, Geet George, Silke Gross, Martin Hagen, Andrea Hausold, Karen J. Heywood, Lutz Hirsch, Marek Jacob, Friedhelm Jansen, Stefan Kinne, Daniel Klocke, Tobias Kölling, Heike Konow, Marie Lothon, Wiebke Mohr, Ann Kristin Naumann, Louise Nuijens, Léa Olivier, Robert Pincus, Mira Pöhlker, Gilles Reverdin, Gregory Roberts, Sabrina Schnitt, Hauke Schulz, A. Pier Siebesma, Claudia Christine Stephan, Peter Sullivan, Ludovic Touzé-Peiffer, Jessica Vial, Raphaela Vogel, Paquita Zuidema, Nicola Alexander, Lyndon Alves, Sophian Arixi, Hamish Asmath, Gholamhossein Bagheri, Katharina Baier, Adriana Bailey, Dariusz Baranowski, Alexandre Baron, Sébastien Barrau, Paul A. Barrett, Frédéric Batier, Andreas Behrendt, Arne Bendinger, Florent Beucher, Sebastien Bigorre, Edmund Blades, Peter Blossey, Olivier Bock, Steven Böing, Pierre Bosser, Denis Bourras, Pascale Bouruet-Aubertot, Keith Bower, Pierre Branellec, Hubert Branger, Michal Brennek, Alan Brewer, Pierre-Etienne Brilouet, Björn Brügmann, Stefan A. Buehler, Elmo Burke, Ralph Burton, Radiance Calmer, Jean-Christophe Canonici, Xavier Carton, Gregory Cato Jr., Jude Andre Charles, Patrick Chazette, Yanxu Chen, Michal T. Chilinski, Thomas Choularton, Patrick Chuang, Shamal Clarke, Hugh Coe, Céline Cornet, Pierre Coutris, Fleur Couvreux, Susanne Crewell, Timothy Cronin, Zhiqiang Cui, Yannis Cuypers, Alton Daley, Gillian M. Damerell, Thibaut Dauhut, Hartwig Deneke, Jean-Philippe Desbios, Steffen Dörner, Sebastian Donner, Vincent Douet, Kyla Drushka, Marina Dütsch, André Ehrlich, Kerry Emanuel, Alexandros Emmanouilidis, Jean-Claude Etienne, Sheryl Etienne-Leblanc, Ghislain Faure, Graham Feingold, Luca Ferrero, Andreas Fix, Cyrille Flamant, Piotr Jacek Flatau, Gregory R. Foltz, Linda Forster, Iulian Furtuna, Alan Gadian, Joseph Galewsky, Martin Gallagher, Peter Gallimore, Cassandra Gaston, Chelle Gentemann, Nicolas Geyskens, Andreas Giez, John Gollop, Isabelle Gouirand, Christophe Gourbeyre, Dörte de Graaf, Geiske E. de Groot, Robert Grosz, Johannes Güttler, Manuel Gutleben, Kashawn Hall, George Harris, Kevin C. Helfer, Dean Henze, Calvert Herbert, Bruna Holanda, Antonio Ibanez-Landeta, Janet Intrieri, Suneil Iyer, Fabrice Julien, Heike Kalesse, Jan Kazil, Alexander Kellman, Abiel T. Kidane, Ulrike Kirchner, Marcus Klingebiel, Mareike Körner, Leslie Ann Kremper, Jan Kretzschmar, Ovid Krüger, Wojciech Kumala, Armin Kurz, Pierre L'Hégaret, Matthieu Labaste, Tom Lachlan-Cope, Arlene Laing, Peter Landschützer, Theresa Lang, Diego Lange, Ingo Lange, Clément Laplace, Gauke Lavik, Rémi Laxenaire, Caroline Le Bihan, Mason Leandro, Nathalie Lefevre, Marius Lena, Donald Lenschow, Qiang Li, Gary Lloyd, Sebastian Los, Niccolò Losi, Oscar Lovell, Christopher Luneau, Przemyslaw Makuch, Szymon Malinowski, Gaston Manta, Eleni Marinou, Nicholas Marsden, Sebastien Masson, Nicolas Maury, Bernhard Mayer, Margarette Mayers-Als, Christophe Mazel, Wayne McGeary, James C. McWilliams, Mario Mech, Melina Mehlmann, Agostino Niyonkuru Meroni, Theresa Mieslinger, Andreas Minikin, Peter Minnett, Gregor Möller, Yanmichel Morfa Avalos, Caroline Muller, Ionela Musat, Anna Napoli, Almuth Neuberger, Christophe Noisel, David Noone, Freja Nordsiek, Jakub L. Nowak, Lothar Oswald, Douglas J. Parker, Carolyn Peck, Renaud Person, Miriam Philippi, Albert Plueddemann, Christopher Pöhlker, Veronika Pörtge, Ulrich Pöschl, Lawrence Pologne, Michał Posyniak, Marc Prange, Estefanía Quiñones Meléndez, Jule Radtke, Karim Ramage, Jens Reimann, Lionel Renault, Klaus Reus, Ashford Reyes, Joachim Ribbe, Maximilian Ringel, Markus Ritschel, Cesar B. Rocha, Nicolas Rochetin, Johannes Röttenbacher, Callum Rollo, Haley Royer, Pauline Sadoulet, Leo Saffin, Sanola Sandiford, Irina Sandu, Michael Schäfer, Vera Schemann, Imke Schirmacher, Oliver Schlenczek, Jerome Schmidt, Marcel Schröder, Alfons Schwarzenboeck, Andrea Sealy, Christoph J. Senff, Ilya Serikov, Samkeyat Shohan, Elizabeth Siddle, Alexander Smirnov, Florian Späth, Branden Spooner, M. Katharina Stolla, Wojciech Szkółka, Simon P. de Szoeke, Stéphane Tarot, Eleni Tetoni, Elizabeth Thompson, Jim Thomson, Lorenzo Tomassini, Julien Totems, Alma Anna Ubele, Leonie Villiger, Jan von Arx, Thomas Wagner, Andi Walther, Ben Webber, Manfred Wendisch, Shanice Whitehall, Anton Wiltshire, Allison A. Wing, Martin Wirth, Jonathan Wiskandt, Kevin Wolf, Ludwig Worbes, Ethan Wright, Volker Wulfmeyer, Shanea Young, Chidong Zhang, Dongxiao Zhang, Florian Ziemen, Tobias Zinner, and Martin Zöger
Earth Syst. Sci. Data, 13, 4067–4119, https://doi.org/10.5194/essd-13-4067-2021, https://doi.org/10.5194/essd-13-4067-2021, 2021
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The EUREC4A field campaign, designed to test hypothesized mechanisms by which clouds respond to warming and benchmark next-generation Earth-system models, is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. It was the first campaign that attempted to characterize the full range of processes and scales influencing trade wind clouds.
Jack Giddings, Karen J. Heywood, Adrian J. Matthews, Manoj M. Joshi, Benjamin G. M. Webber, Alejandra Sanchez-Franks, Brian A. King, and Puthenveettil N. Vinayachandran
Ocean Sci., 17, 871–890, https://doi.org/10.5194/os-17-871-2021, https://doi.org/10.5194/os-17-871-2021, 2021
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Little is known about the impact of chlorophyll on SST in the Bay of Bengal (BoB). Solar irradiance measured by an ocean glider and three Argo floats is used to determine the effect of chlorophyll on BoB SST during the 2016 summer monsoon. The Southwest Monsoon Current has high chlorophyll concentrations (∼0.5 mg m−3) and shallow solar penetration depths (∼14 m). Ocean mixed layer model simulations show that SST increases by 0.35°C per month, with the potential to influence monsoon rainfall.
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Short summary
Using an underwater buoyancy-powered autonomous glider, we collected profiles of temperature and salinity from the ocean north-east of Barbados. Most of the temperature and salinity profiles contained staircase-like structures of alternating constant values and large gradients. We wrote an algorithm to identify these staircases. We hypothesise that these staircases are prevented from forming where background gradients in temperature and salinity are too great.
Using an underwater buoyancy-powered autonomous glider, we collected profiles of temperature and...
