Articles | Volume 8, issue 10
https://doi.org/10.5194/gmd-8-3119-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Special issue:
https://doi.org/10.5194/gmd-8-3119-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Development and technical paper
| 
06 Oct 2015
Development and technical paper |
| 06 Oct 2015
Increasing vertical mixing to reduce Southern Ocean deep convection in NEMO3.4
Centre for Ocean and Atmospheric Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
Met Office, Hadley Centre, Exeter, EX1 3PB, UK
now at: Department of Marine Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
J. K. Ridley
Met Office, Hadley Centre, Exeter, EX1 3PB, UK
D. Calvert
Met Office, Hadley Centre, Exeter, EX1 3PB, UK
D. P. Stevens
Centre for Ocean and Atmospheric Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
K. J. Heywood
Centre for Ocean and Atmospheric Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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Polynyas are "holes" in the sea-ice cover where large amounts of new ice form, but they are not represented in climate models. We used a novel sea-ice model, compared against satellite data, to study Arctic polynya activity over 18 winters. We found that polynyas account for up to 11 % of total winter ice production in the Arctic, despite only covering a small area. Our results suggest that earlier satellite estimates may have been too high.
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Polynyas, openings in the sea ice, play a crucial role in the Arctic winter icescape, notably acting as breathing hole for the ecosystem, hunting ground for Indigenous communities, and comparatively safe navigation alternative. The Arctic being the region of the world changing fastest in response to climate change, we here review how polynyas and their impact on the climate have been changing too, and, for lack of adequate long-term observations or models, extrapolate their future.
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Ocean Sci., 20, 917–930, https://doi.org/10.5194/os-20-917-2024, https://doi.org/10.5194/os-20-917-2024, 2024
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Polynyas are "holes" in the sea-ice cover where large amounts of new ice form, but they are not represented in climate models. We used a novel sea-ice model, compared against satellite data, to study Arctic polynya activity over 18 winters. We found that polynyas account for up to 11 % of total winter ice production in the Arctic, despite only covering a small area. Our results suggest that earlier satellite estimates may have been too high.
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EGUsphere, https://doi.org/10.5194/egusphere-2026-3855, https://doi.org/10.5194/egusphere-2026-3855, 2026
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Polynyas, openings in the sea ice, play a crucial role in the Arctic winter icescape, notably acting as breathing hole for the ecosystem, hunting ground for Indigenous communities, and comparatively safe navigation alternative. The Arctic being the region of the world changing fastest in response to climate change, we here review how polynyas and their impact on the climate have been changing too, and, for lack of adequate long-term observations or models, extrapolate their future.
Prince Xavier, Martin Willett, Tim Graham, Paul Earnshaw, Dan Copsey, Nikesh Narayan, Charline Marzin, Alistair Sellar, Duncan Ackerley, Adam Blaker, Ed Blockley, Alejandro Bodas-Salcedo, Andrew Bushell, Nakbin Choi, Xin Rong Chua, Catherine Guiavarc'h, Muhammad Hassim, Julian Heming, Debra Hudson, Sarah Ineson, Anthony Jones, Colin Jones, Richard Keane, Kiwook Kim, Jiyeong Kim, Till Kuhlbrodt, Myong-In Lee, Richard Levine, Chen Li, Gill Martin, Alex Megann, Anne Mccabe, Aurel Moise, Leighton Regayre, Jeff Ridley, Luke Roberts, Sandeep Sahany, Reinhard K. H. Schiemann, David Storkey, Warren Tennant, Lorenzo Tomassini, Yoko Tsushima, Graham P. Weedon, Alex West, Matthew C. Wheeler, Keith Williams, Xiaobing Zhou, and Hongyan Zhu
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This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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Baylor Fox-Kemper, Patricia DeRepentigny, Anne Marie Treguier, Christian Stepanek, Eleanor O'Rourke, Chloe Mackallah, Alberto Meucci, Yevgeny Aksenov, Paul J. Durack, Nicole Feldl, Oluwayemi Garuba, Vanessa Hernaman, Céline Heuzé, Doroteaciro Iovino, Gaurav Madan, André L. Marquez, François Massonnet, Jenny Mecking, Dhrubajyoti Samanta, Patrick C. Taylor, Wan-Ling Tseng, and Martin Vancoppenolle
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The ocean and sea ice are central to Earth's climate system, influencing global heat and carbon cycles, weather patterns, and sea level rise. Here the earth system model variables needed for studies of the ocean and sea ice are prioritized and requested. These requested variables were developed through an international, community-based process.
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Short summary
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When the sea ice opens in winter in so-called “polynyas”, the entire climate system is affected from deep water ventilation to cloud formation, along with the ecosystem. In observations, winter Arctic polynyas have been increasing along with climate change. We here show that we cannot predict their future using global climate models as they do not represent winter Arctic polynyas correctly: they open over too large areas but too rarely, and for the wrong reason.
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Andrew G. Pauling, Inga J. Smith, Torge Martin, Jeff K. Ridley, David P. Stevens, Max Thomas, Rebecca L. Beadling, Christopher Danek, Tore Hattermann, Qian Li, John Marshall, Morven Muilwijk, Ariaan Purich, and Neil C. Swart
EGUsphere, https://doi.org/10.5194/egusphere-2026-658, https://doi.org/10.5194/egusphere-2026-658, 2026
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Climate models typically do not include meltwater entering the Southern Ocean due to Antarctic ice sheet mass loss. Previous work shows this meltwater drives sea ice growth, but the varying responses have been difficult to compare across models. We ran 11 climate models using the same meltwater input and found a wide range of sea ice responses depending on the background state in each model. Understanding this uncertainty in response is important for future projections of Antarctic sea ice.
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.
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.
Céline Heuzé and Carmen Hau Man Wong
The Cryosphere, 19, 6043–6058, https://doi.org/10.5194/tc-19-6043-2025, https://doi.org/10.5194/tc-19-6043-2025, 2025
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Polynyas are areas with no- or thin-ice within the ice pack. They play a crucial role for the Earth system, yet their monitoring in the Arctic is challenging because polynya detection is non-trivial. We here demonstrate that polynyas can successfully be detected with a novel, machine-learning based method. In fact, we argue that they are better detected than with traditional methods, which seem to fail as sea ice decreases because of climate change.
Alison J. McLaren, Louise C. Sime, Simon Wilson, Jeff Ridley, Qinggang Gao, Merve Gorguner, Giorgia Line, Martin Werner, and Paul Valdes
Geosci. Model Dev., 18, 8129–8142, https://doi.org/10.5194/gmd-18-8129-2025, https://doi.org/10.5194/gmd-18-8129-2025, 2025
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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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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.
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.
Céline Heuzé, Linn Carlstedt, Lea Poropat, and Heather Reese
Ocean Sci., 21, 1813–1832, https://doi.org/10.5194/os-21-1813-2025, https://doi.org/10.5194/os-21-1813-2025, 2025
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Extreme sea levels will worsen under climate change. In northern Europe, what drives these extreme events will not change, so determining these drivers is of use for planning coastal defences. Here, using two machine learning methods on hourly tide gauge and weather data at nine locations around the North and Baltic seas, we determine that the drivers of prolonged periods of high sea level are westerly winds, whereas the drivers of the most extreme peaks depend on the coastline geometry.
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.
David Storkey, Pierre Mathiot, Michael J. Bell, Dan Copsey, Catherine Guiavarc'h, Helene T. Hewitt, Jeff Ridley, and Malcolm J. Roberts
Geosci. Model Dev., 18, 2725–2745, https://doi.org/10.5194/gmd-18-2725-2025, https://doi.org/10.5194/gmd-18-2725-2025, 2025
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The Southern Ocean is a key region of the world ocean in the context of climate change studies. We show that the Met Office Hadley Centre coupled model with intermediate ocean resolution struggles to accurately simulate the Southern Ocean. Increasing the frictional drag that the seafloor exerts on ocean currents and introducing a representation of unresolved ocean eddies both appear to reduce the large-scale biases in this model.
Flor Vermassen, Clare Bird, Tirza M. Weitkamp, Kate F. Darling, Hanna Farnelid, Céline Heuzé, Allison Y. Hsiang, Salar Karam, Christian Stranne, Marcus Sundbom, and Helen K. Coxall
Biogeosciences, 22, 2261–2286, https://doi.org/10.5194/bg-22-2261-2025, https://doi.org/10.5194/bg-22-2261-2025, 2025
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We provide the first systematic survey of planktonic foraminifera in the high Arctic Ocean. Our results describe the abundance and species composition under summer sea ice. They indicate that the polar specialist N. pachyderma is the only species present, with subpolar species absent. The data set will be a valuable reference for continued monitoring of the state of planktonic foraminifera communities as they respond to the ongoing sea-ice decline and the “Atlantification” of the Arctic Ocean.
Catherine Guiavarc'h, David Storkey, Adam T. Blaker, Ed Blockley, Alex Megann, Helene Hewitt, Michael J. Bell, Daley Calvert, Dan Copsey, Bablu Sinha, Sophia Moreton, Pierre Mathiot, and Bo An
Geosci. Model Dev., 18, 377–403, https://doi.org/10.5194/gmd-18-377-2025, https://doi.org/10.5194/gmd-18-377-2025, 2025
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The Global Ocean and Sea Ice configuration version 9 (GOSI9) is the new UK hierarchy of model configurations based on the Nucleus for European Modelling of the Ocean (NEMO) and available at three resolutions. It will be used for various applications, e.g. weather forecasting and climate prediction. It improves upon the previous version by reducing global temperature and salinity biases and enhancing the representation of Arctic sea ice and the Antarctic Circumpolar Current.
Ed Blockley, Emma Fiedler, Jeff Ridley, Luke Roberts, Alex West, Dan Copsey, Daniel Feltham, Tim Graham, David Livings, Clement Rousset, David Schroeder, and Martin Vancoppenolle
Geosci. Model Dev., 17, 6799–6817, https://doi.org/10.5194/gmd-17-6799-2024, https://doi.org/10.5194/gmd-17-6799-2024, 2024
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This paper documents the sea ice model component of the latest Met Office coupled model configuration, which will be used as the physical basis for UK contributions to CMIP7. Documentation of science options used in the configuration are given along with a brief model evaluation. This is the first UK configuration to use NEMO’s new SI3 sea ice model. We provide details on how SI3 was adapted to work with Met Office coupling methodology and documentation of coupling processes in the model.
Salar Karam, Céline Heuzé, Mario Hoppmann, and Laura de Steur
Ocean Sci., 20, 917–930, https://doi.org/10.5194/os-20-917-2024, https://doi.org/10.5194/os-20-917-2024, 2024
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A long-term mooring array in the Fram Strait allows for an evaluation of decadal trends in temperature in this major oceanic gateway into the Arctic. Since the 1980s, the deep waters of the Greenland Sea and the Eurasian Basin of the Arctic have warmed rapidly at a rate of 0.11°C and 0.05°C per decade, respectively, at a depth of 2500 m. We show that the temperatures of the two basins converged around 2017 and that the deep waters of the Greenland Sea are now a heat source for the Arctic Ocean.
Lea Poropat, Dani Jones, Simon D. A. Thomas, and Céline Heuzé
Ocean Sci., 20, 201–215, https://doi.org/10.5194/os-20-201-2024, https://doi.org/10.5194/os-20-201-2024, 2024
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In this study we use a machine learning method called a Gaussian mixture model to divide part of the ocean (northwestern European seas and part of the Atlantic Ocean) into regions based on satellite observations of sea level. This helps us study each of these regions separately and learn more about what causes sea level changes there. We find that the ocean is first divided based on bathymetry and then based on other features such as water masses and typical atmospheric conditions.
Céline Heuzé, Oliver Huhn, Maren Walter, Natalia Sukhikh, Salar Karam, Wiebke Körtke, Myriel Vredenborg, Klaus Bulsiewicz, Jürgen Sültenfuß, Ying-Chih Fang, Christian Mertens, Benjamin Rabe, Sandra Tippenhauer, Jacob Allerholt, Hailun He, David Kuhlmey, Ivan Kuznetsov, and Maria Mallet
Earth Syst. Sci. Data, 15, 5517–5534, https://doi.org/10.5194/essd-15-5517-2023, https://doi.org/10.5194/essd-15-5517-2023, 2023
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Gases dissolved in the ocean water not used by the ecosystem (or "passive tracers") are invaluable to track water over long distances and investigate the processes that modify its properties. Unfortunately, especially so in the ice-covered Arctic Ocean, such gas measurements are sparse. We here present a data set of several passive tracers (anthropogenic gases, noble gases and their isotopes) collected over the full ocean depth, weekly, during the 1-year drift in the Arctic during MOSAiC.
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.
Maria Vittoria Guarino, Louise C. Sime, Rachel Diamond, Jeff Ridley, and David Schroeder
Clim. Past, 19, 865–881, https://doi.org/10.5194/cp-19-865-2023, https://doi.org/10.5194/cp-19-865-2023, 2023
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We investigate the response of the atmosphere, ocean, and ice domains to the release of a large volume of glacial meltwaters thought to have occurred during the Last Interglacial period. We show that the signal that originated in the North Atlantic travels over great distances across the globe. It modifies the ocean gyre circulation in the Northern Hemisphere as well as the belt of westerly winds in the Southern Hemisphere, with consequences for Antarctic sea ice.
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.
Callum Rollo, Karen J. Heywood, and Rob A. Hall
Geosci. Instrum. Method. Data Syst., 11, 359–373, https://doi.org/10.5194/gi-11-359-2022, https://doi.org/10.5194/gi-11-359-2022, 2022
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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.
Antony Siahaan, Robin S. Smith, Paul R. Holland, Adrian Jenkins, Jonathan M. Gregory, Victoria Lee, Pierre Mathiot, Antony J. Payne, Jeff K. Ridley, and Colin G. Jones
The Cryosphere, 16, 4053–4086, https://doi.org/10.5194/tc-16-4053-2022, https://doi.org/10.5194/tc-16-4053-2022, 2022
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The UK Earth System Model is the first to fully include interactions of the atmosphere and ocean with the Antarctic Ice Sheet. Under the low-greenhouse-gas SSP1–1.9 (Shared Socioeconomic Pathway) scenario, the ice sheet remains stable over the 21st century. Under the strong-greenhouse-gas SSP5–8.5 scenario, the model predicts strong increases in melting of large ice shelves and snow accumulation on the surface. The dominance of accumulation leads to a sea level fall at the end of the century.
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.
Adam William Bateson, Daniel L. Feltham, David Schröder, Yanan Wang, Byongjun Hwang, Jeff K. Ridley, and Yevgeny Aksenov
The Cryosphere, 16, 2565–2593, https://doi.org/10.5194/tc-16-2565-2022, https://doi.org/10.5194/tc-16-2565-2022, 2022
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Numerical models are used to understand the mechanisms that drive the evolution of the Arctic sea ice cover. The sea ice cover is formed of pieces of ice called floes. Several recent studies have proposed variable floe size models to replace the standard model assumption of a fixed floe size. In this study we show the need to include floe fragmentation processes in these variable floe size models and demonstrate that model design can determine the impact of floe size on size ice evolution.
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.
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Short summary
Most ocean models, including NEMO, have unrealistic Southern Ocean deep convection. That is, through extensive areas of the Southern Ocean, they exhibit convection from the surface of the ocean to the sea floor. We find this convection to be an issue as it impacts the whole ocean circulation, notably strengthening the Antarctic Circumpolar Current. Using sensitivity experiments, we show that counter-intuitively the vertical mixing needs to be enhanced to reduce this spurious convection.
Most ocean models, including NEMO, have unrealistic Southern Ocean deep convection. That is,...
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