Articles | Volume 21, issue 4
https://doi.org/10.5194/os-21-1609-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-21-1609-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
30 Jul 2025
Research article |
| 30 Jul 2025
| 30 Jul 2025
Satellite-derived steric height in the Southern Ocean: trends, variability, and climate drivers
National Oceanography Centre, Southampton, SO14 3ZH, UK
Institute for Climate and Atmospheric Science, University of Leeds, Leeds, LS2 9JT, UK
Alessandro Silvano
School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
Alberto C. Naveira Garabato
School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
Oana Dragomir
School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
Balearic Islands Coastal Observing and Forecasting System, 07121 Palma, Balearic Islands, Spain
Noémie Schifano
Laboratoire d’Océanographie Physique et Spatiale (LOPS), Univ Brest, CNRS, IUEM, Brest, France
Anna E. Hogg
Institute for Climate and Atmospheric Science, University of Leeds, Leeds, LS2 9JT, UK
Alice Marzocchi
National Oceanography Centre, Southampton, SO14 3ZH, UK
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Zanna Chase, Karen E. Kohfeld, Amy Leventer, David Lund, Xavier Crosta, Laurie Menviel, Helen C. Bostock, Matthew Chadwick, Samuel L. Jaccard, Jacob Jones, Alice Marzocchi, Katrin J. Meissner, Elisabeth Sikes, Louise C. Sime, and Luke Skinner
EGUsphere, https://doi.org/10.5194/egusphere-2025-3504, https://doi.org/10.5194/egusphere-2025-3504, 2025
This preprint is open for discussion and under review for Climate of the Past (CP).
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The impact of recent dramatic declines in Antarctic sea ice on the Earth system are uncertain. We reviewed how sea ice affects ocean circulation, ice sheets, winds, and the carbon cycle by considering theory and modern observations alongside paleo-proxy reconstructions. We found evidence for connections between sea ice and these systems but also conflicting results, which point to missing knowledge. Our work highlights the complex role of sea ice in the Earth system.
Benjamin J. Davison, Anna E. Hogg, Thomas Slater, Richard Rigby, and Nicolaj Hansen
Earth Syst. Sci. Data, 17, 3259–3281, https://doi.org/10.5194/essd-17-3259-2025, https://doi.org/10.5194/essd-17-3259-2025, 2025
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Grounding line discharge is a measure of the amount of ice entering the ocean from an ice mass. This paper describes a dataset of grounding line discharge for the Antarctic Ice Sheet and each of its glaciers. The dataset shows that Antarctic Ice Sheet grounding line discharge has increased since 1996.
Hugues Goosse, Stephy Libera, Alberto C. Naveira Garabato, Benjamin Richaud, Alessandro Silvano, and Martin Vancoppenolle
EGUsphere, https://doi.org/10.5194/egusphere-2025-1837, https://doi.org/10.5194/egusphere-2025-1837, 2025
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The position of the winter sea ice edge in the Southern Ocean is strongly linked to the one of the Antarctic Circumpolar Current and thus to ocean bathymetry. This is due to the influence of the Antarctic Circumpolar Current on the southward heat flux that limits sea ice expansion, directly through oceanic processes and indirectly through its influence on atmospheric heat transport.
Heather L. Selley, Anna E. Hogg, Benjamin J. Davison, Pierre Dutrieux, and Thomas Slater
The Cryosphere, 19, 1725–1738, https://doi.org/10.5194/tc-19-1725-2025, https://doi.org/10.5194/tc-19-1725-2025, 2025
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We used satellite observations to measure recent changes in ice speed and flow direction in the Pope, Smith, and Kohler region of West Antarctica (2005–2022). We found substantial speed-up on seven ice streams of up to 87 %. However, Kohler West Glacier has slowed by 10 %, due to the redirection of ice flow into its rapidly thinning neighbour. This process of “ice piracy” has not previously been directly observed on this rapid timescale and may influence future ice shelf and sheet mass changes.
Verónica González-Gambau, Estrella Olmedo, Aina García-Espriu, Cristina González-Haro, Antonio Turiel, Carolina Gabarró, Alessandro Silvano, Aditya Narayanan, Alberto Naveira-Garabato, Rafael Catany, Nina Hoareau, Marta Umbert, Giuseppe Aulicino, Yuri Cotroneo, Roberto Sabia, and Diego Fernández-Prieto
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-212, https://doi.org/10.5194/essd-2025-212, 2025
Revised manuscript under review for ESSD
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This paper introduces a new Sea Surface Salinity product for the Southern Ocean, based on SMOS data and developed by the Barcelona Expert Center. It offers 9-day maps on a 25 km EASE-SL grid, from 2011 to 2023, covering areas south of 30° S. The product is accurate beyond 150 km from sea ice, with nearly zero bias and a ~0.22 STD. It tracks well seasonal and interannual changes and will contribute to the understanding of processes influenced by upper-ocean salinity, including ice formation/melt.
Yikai Zhu, Anna E. Hogg, Andrew Hooper, and Benjamin J. Wallis
EGUsphere, https://doi.org/10.5194/egusphere-2025-849, https://doi.org/10.5194/egusphere-2025-849, 2025
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This study investigates the long- and short-term changes in the grounding line of the Amery Ice Shelf in East Antarctica, using satellite observations and a method called Differential Range Offset Tracking (DROT). Our findings show how the grounding line behaves in response to tides and other environmental factors, with implications for understanding ice shelf stability.
Lu Zhou, Holly Ayres, Birte Gülk, Aditya Narayanan, Casimir de Lavergne, Malin Ödalen, Alessandro Silvano, Xingchi Wang, Margaret Lindeman, and Nadine Steiger
EGUsphere, https://doi.org/10.5194/egusphere-2025-999, https://doi.org/10.5194/egusphere-2025-999, 2025
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Polynyas are large openings in polar sea ice that can influence global climate and ocean circulation. After disappearing for 40 years, major polynyas reappeared in the Weddell Sea in 2016 and 2017, sparking new scientific questions. Our review explores how ocean currents, atmospheric conditions, and deep ocean heat drive their formation. These polynyas impact ecosystems, carbon exchange, and deep water formation, but their future remains uncertain, requiring better observations and models.
Shenjie Zhou, Pierre Dutrieux, Claudia F. Giulivi, Adrian Jenkins, Alessandro Silvano, Christopher Auckland, E. Povl Abrahamsen, Michael P. Meredith, Irena Vaňková, Keith W. Nicholls, Peter E. D. Davis, Svein Østerhus, Arnold L. Gordon, Christopher J. Zappa, Tiago S. Dotto, Theodore A. Scambos, Kathyrn 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 Discuss., https://doi.org/10.5194/essd-2025-54, https://doi.org/10.5194/essd-2025-54, 2025
Revised manuscript under review for ESSD
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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.
Katie Lowery, Pierre Dutrieux, Paul R. Holland, Anna E. Hogg, Noel Gourmelen, and Benjamin J. Wallis
EGUsphere, https://doi.org/10.5194/egusphere-2025-267, https://doi.org/10.5194/egusphere-2025-267, 2025
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We use CryoSat-2 to observe monthly changes in Pine Island Glacier's ice shelf (PIG) surface at 250 m resolution. We show that melt is focused on the western walls of basal channels and highlight the role of channels in grounding pinning points. PIG’s main channel geometry is inherited from the ice-bed interface upstream of the grounding line. These results highlight the importance of channels on ice shelf stability and how this can change over time.
Benjamin J. Wallis, Anna E. Hogg, Yikai Zhu, and Andrew Hooper
The Cryosphere, 18, 4723–4742, https://doi.org/10.5194/tc-18-4723-2024, https://doi.org/10.5194/tc-18-4723-2024, 2024
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The grounding line, where ice begins to float, is an essential variable to understand ice dynamics, but in some locations it can be challenging to measure with established techniques. Using satellite data and a new method, Wallis et al. measure the grounding line position of glaciers and ice shelves in the Antarctic Peninsula and find retreats of up to 16.3 km have occurred since the last time measurements were made in the 1990s.
Trystan Surawy-Stepney, Stephen L. Cornford, and Anna E. Hogg
EGUsphere, https://doi.org/10.5194/egusphere-2024-2438, https://doi.org/10.5194/egusphere-2024-2438, 2024
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The speed at which Antarctic ice flows is dependent on its viscosity and the sliperiness of the ice/bedrock interface. Often, these unknown variables are inferred from observations of ice speed. This article presents an attempt to make this difficult procedure easier by making use of additional information in the form of observations of crevasses, which make ice appear less viscous to numerical models. We find in some circumstances that this leads to more appealing solutions to this problem.
Benjamin J. Davison, Anna E. Hogg, Carlos Moffat, Michael P. Meredith, and Benjamin J. Wallis
The Cryosphere, 18, 3237–3251, https://doi.org/10.5194/tc-18-3237-2024, https://doi.org/10.5194/tc-18-3237-2024, 2024
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Using a new dataset of ice motion, we observed glacier acceleration on the west coast of the Antarctic Peninsula. The speed-up began around January 2021, but some glaciers sped up earlier or later. Using a combination of ship-based ocean temperature observations and climate models, we show that the speed-up coincided with a period of unusually warm air and ocean temperatures in the region.
Clara Celestine Douglas, Nathan Briggs, Peter Brown, Graeme MacGilchrist, and Alberto Naveira Garabato
Ocean Sci., 20, 475–497, https://doi.org/10.5194/os-20-475-2024, https://doi.org/10.5194/os-20-475-2024, 2024
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We use data from satellites and robotic floats to assess what drives year-to-year variability in primary production in the Weddell Gyre. We find that the maximum area of ice-free water in the summer is important in determining the total primary production in the region but that areas that are ice free for longer than 120 d become nutrient limited. This has potential implications for ecosystem health in a warming world, where a decline in sea ice cover will affect total primary production.
Phoebe A. Hudson, Adrien C. H. Martin, Simon A. Josey, Alice Marzocchi, and Athanasios Angeloudis
Ocean Sci., 20, 341–367, https://doi.org/10.5194/os-20-341-2024, https://doi.org/10.5194/os-20-341-2024, 2024
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Satellite salinity data are used for the first time to study variability in Arctic freshwater transport from the Lena River and are shown to be a valuable tool for studying this region. These data confirm east/westerly wind is the main control on fresh water and sea ice transport rather than the volume of river runoff. The strong role of the wind suggests understanding how wind patterns will change is key to predicting future Arctic circulation and sea ice concentration.
Trystan Surawy-Stepney, Anna E. Hogg, Stephen L. Cornford, Benjamin J. Wallis, Benjamin J. Davison, Heather L. Selley, Ross A. W. Slater, Elise K. Lie, Livia Jakob, Andrew Ridout, Noel Gourmelen, Bryony I. D. Freer, Sally F. Wilson, and Andrew Shepherd
The Cryosphere, 18, 977–993, https://doi.org/10.5194/tc-18-977-2024, https://doi.org/10.5194/tc-18-977-2024, 2024
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Here, we use satellite observations and an ice flow model to quantify the impact of sea ice buttressing on ice streams on the Antarctic Peninsula. The evacuation of 11-year-old landfast sea ice in the Larsen B embayment on the East Antarctic Peninsula in January 2022 was closely followed by major changes in the calving behaviour and acceleration (30 %) of the ocean-terminating glaciers. Our results show that sea ice buttressing had a negligible direct role in the observed dynamic changes.
Trystan Surawy-Stepney, Anna E. Hogg, Stephen L. Cornford, and David C. Hogg
The Cryosphere, 17, 4421–4445, https://doi.org/10.5194/tc-17-4421-2023, https://doi.org/10.5194/tc-17-4421-2023, 2023
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The presence of crevasses in Antarctica influences how the ice sheet behaves. It is important, therefore, to collect data on the spatial distribution of crevasses and how they are changing. We present a method of mapping crevasses from satellite radar imagery and apply it to 7.5 years of images, covering Antarctica's floating and grounded ice. We develop a method of measuring change in the density of crevasses and quantify increased fracturing in important parts of the West Antarctic Ice Sheet.
Bryony I. D. Freer, Oliver J. Marsh, Anna E. Hogg, Helen Amanda Fricker, and Laurie Padman
The Cryosphere, 17, 4079–4101, https://doi.org/10.5194/tc-17-4079-2023, https://doi.org/10.5194/tc-17-4079-2023, 2023
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We develop a method using ICESat-2 data to measure how Antarctic grounding lines (GLs) migrate across the tide cycle. At an ice plain on the Ronne Ice Shelf we observe 15 km of tidal GL migration, the largest reported distance in Antarctica, dominating any signal of long-term migration. We identify four distinct migration modes, which provide both observational support for models of tidal ice flexure and GL migration and insights into ice shelf–ocean–subglacial interactions in grounding zones.
Dani C. Jones, Maike Sonnewald, Shenjie Zhou, Ute Hausmann, Andrew J. S. Meijers, Isabella Rosso, Lars Boehme, Michael P. Meredith, and Alberto C. Naveira Garabato
Ocean Sci., 19, 857–885, https://doi.org/10.5194/os-19-857-2023, https://doi.org/10.5194/os-19-857-2023, 2023
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Machine learning is transforming oceanography. For example, unsupervised classification approaches help researchers identify underappreciated structures in ocean data, helping to generate new hypotheses. In this work, we use a type of unsupervised classification to identify structures in the temperature and salinity structure of the Weddell Gyre, which is an important region for global ocean circulation and for climate. We use our method to generate new ideas about mixing in the Weddell Gyre.
Julia R. Andreasen, Anna E. Hogg, and Heather L. Selley
The Cryosphere, 17, 2059–2072, https://doi.org/10.5194/tc-17-2059-2023, https://doi.org/10.5194/tc-17-2059-2023, 2023
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There are few long-term, high spatial resolution observations of ice shelf change in Antarctica over the past 3 decades. In this study, we use high spatial resolution observations to map the annual calving front location on 34 ice shelves around Antarctica from 2009 to 2019 using satellite data. The results provide a comprehensive assessment of ice front migration across Antarctica over the last decade.
Stefanie L. Ypma, Quinten Bohte, Alexander Forryan, Alberto C. Naveira Garabato, Andy Donnelly, and Erik van Sebille
Ocean Sci., 18, 1477–1490, https://doi.org/10.5194/os-18-1477-2022, https://doi.org/10.5194/os-18-1477-2022, 2022
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In this research we aim to improve cleanup efforts on the Galapagos Islands of marine plastic debris when resources are limited and the distribution of the plastic on shorelines is unknown. Using a network that describes the flow of macroplastic between the islands we have identified the most efficient cleanup locations, quantified the impact of targeting these locations and showed that shorelines where the plastic is unlikely to leave are likely efficient cleanup locations.
Xavier Crosta, Karen E. Kohfeld, Helen C. Bostock, Matthew Chadwick, Alice Du Vivier, Oliver Esper, Johan Etourneau, Jacob Jones, Amy Leventer, Juliane Müller, Rachael H. Rhodes, Claire S. Allen, Pooja Ghadi, Nele Lamping, Carina B. Lange, Kelly-Anne Lawler, David Lund, Alice Marzocchi, Katrin J. Meissner, Laurie Menviel, Abhilash Nair, Molly Patterson, Jennifer Pike, Joseph G. Prebble, Christina Riesselman, Henrik Sadatzki, Louise C. Sime, Sunil K. Shukla, Lena Thöle, Maria-Elena Vorrath, Wenshen Xiao, and Jiao Yang
Clim. Past, 18, 1729–1756, https://doi.org/10.5194/cp-18-1729-2022, https://doi.org/10.5194/cp-18-1729-2022, 2022
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Despite its importance in the global climate, our knowledge of Antarctic sea-ice changes throughout the last glacial–interglacial cycle is extremely limited. As part of the Cycles of Sea Ice Dynamics in the Earth system (C-SIDE) Working Group, we review marine- and ice-core-based sea-ice proxies to provide insights into their applicability and limitations. By compiling published records, we provide information on Antarctic sea-ice dynamics over the past 130 000 years.
Martin Horwath, Benjamin D. Gutknecht, Anny Cazenave, Hindumathi Kulaiappan Palanisamy, Florence Marti, Ben Marzeion, Frank Paul, Raymond Le Bris, Anna E. Hogg, Inès Otosaka, Andrew Shepherd, Petra Döll, Denise Cáceres, Hannes Müller Schmied, Johnny A. Johannessen, Jan Even Øie Nilsen, Roshin P. Raj, René Forsberg, Louise Sandberg Sørensen, Valentina R. Barletta, Sebastian B. Simonsen, Per Knudsen, Ole Baltazar Andersen, Heidi Ranndal, Stine K. Rose, Christopher J. Merchant, Claire R. Macintosh, Karina von Schuckmann, Kristin Novotny, Andreas Groh, Marco Restano, and Jérôme Benveniste
Earth Syst. Sci. Data, 14, 411–447, https://doi.org/10.5194/essd-14-411-2022, https://doi.org/10.5194/essd-14-411-2022, 2022
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Global mean sea-level change observed from 1993 to 2016 (mean rate of 3.05 mm yr−1) matches the combined effect of changes in water density (thermal expansion) and ocean mass. Ocean-mass change has been assessed through the contributions from glaciers, ice sheets, and land water storage or directly from satellite data since 2003. Our budget assessments of linear trends and monthly anomalies utilise new datasets and uncertainty characterisations developed within ESA's Climate Change Initiative.
Alice Marzocchi, A. J. George Nurser, Louis Clément, and Elaine L. McDonagh
Ocean Sci., 17, 935–952, https://doi.org/10.5194/os-17-935-2021, https://doi.org/10.5194/os-17-935-2021, 2021
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The ocean absorbs a large proportion of the excess heat and anthropogenic carbon in the climate system. This uptake is modulated by air–sea fluxes and by the processes that transport water from the surface into the ocean’s interior. We performed numerical simulations with interannually varying passive tracers and identified the key role of surface atmospheric forcing in setting the longer-term variability in the distribution of the tracers after they are transported below the ocean’s surface.
Pieter Demuynck, Toby Tyrrell, Alberto Naveira Garabato, Mark Christopher Moore, and Adrian Peter Martin
Biogeosciences, 17, 2289–2314, https://doi.org/10.5194/bg-17-2289-2020, https://doi.org/10.5194/bg-17-2289-2020, 2020
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The availability of macronutrients N and Si is of key importance to sustain life in the Southern Ocean. N and Si are available in abundance at the southern boundary of the Southern Ocean due to constant supply from the deep ocean. In the more northern regions of the Southern Ocean, a decline in macronutrient concentration is noticed, especially strong for Si rather than N. This paper uses a simplified biogeochemical model to investigate processes responsible for this decline in concentration.
Jan D. Zika, Jean-Baptiste Sallée, Andrew J. S. Meijers, Alberto C. Naveira-Garabato, Andrew J. Watson, Marie-Jose Messias, and Brian A. King
Ocean Sci., 16, 323–336, https://doi.org/10.5194/os-16-323-2020, https://doi.org/10.5194/os-16-323-2020, 2020
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The ocean can regulate climate by distributing heat and carbon dioxide into its interior. This work has resulted from a major experiment aimed at understanding how that distribution occurs. In the experiment an artificial tracer was released into the ocean. After release the tracer was tracked as it was distorted by ocean currents. Using novel methods we reveal how the tracer's distortions follow the movement of the underlying water masses in the ocean and we estimate the rate at which it mixes.
Alexander Forryan, Sheldon Bacon, Takamasa Tsubouchi, Sinhué Torres-Valdés, and Alberto C. Naveira Garabato
The Cryosphere, 13, 2111–2131, https://doi.org/10.5194/tc-13-2111-2019, https://doi.org/10.5194/tc-13-2111-2019, 2019
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We compare control volume and geochemical tracer-based methods of estimating the Arctic Ocean freshwater budget and find both methods in good agreement. Inconsistencies arise from the distinction between
Atlanticand
Pacificwaters in the geochemical calculations. The definition of Pacific waters is particularly problematic due to the non-conservative nature of the nutrients underpinning the definition and the low salinity characterizing waters entering the Arctic through Bering Strait.
Adriano Lemos, Andrew Shepherd, Malcolm McMillan, Anna E. Hogg, Emma Hatton, and Ian Joughin
The Cryosphere, 12, 2087–2097, https://doi.org/10.5194/tc-12-2087-2018, https://doi.org/10.5194/tc-12-2087-2018, 2018
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We present time-series of ice surface velocities on four key outlet glaciers in Greenland, derived from sequential satellite imagery acquired between October 2014 and February 2017. We demonstrate it is possible to resolve seasonal and inter-annual changes in outlet glacier with an estimated certainty of 10 %. These datasets are key for the timely identification of emerging signals of dynamic imbalance and for understanding the processes driving ice velocity change.
Damon Davies, Robert G. Bingham, Edward C. King, Andrew M. Smith, Alex M. Brisbourne, Matteo Spagnolo, Alastair G. C. Graham, Anna E. Hogg, and David G. Vaughan
The Cryosphere, 12, 1615–1628, https://doi.org/10.5194/tc-12-1615-2018, https://doi.org/10.5194/tc-12-1615-2018, 2018
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This paper investigates the dynamics of ice stream beds using repeat geophysical surveys of the bed of Pine Island Glacier, West Antarctica; 60 km of the bed was surveyed, comprising the most extensive repeat ground-based geophysical surveys of an Antarctic ice stream; 90 % of the surveyed bed shows no significant change despite the glacier increasing in speed by up to 40 % over the last decade. This result suggests that ice stream beds are potentially more stable than previously suggested.
Thomas Slater, Andrew Shepherd, Malcolm McMillan, Alan Muir, Lin Gilbert, Anna E. Hogg, Hannes Konrad, and Tommaso Parrinello
The Cryosphere, 12, 1551–1562, https://doi.org/10.5194/tc-12-1551-2018, https://doi.org/10.5194/tc-12-1551-2018, 2018
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We present a new digital elevation model of Antarctica derived from 6 years of elevation measurements acquired by ESA's CryoSat-2 satellite radar altimeter. We compare our elevation model to an independent set of NASA IceBridge airborne laser altimeter measurements and find the overall accuracy to be 9.5 m – a value comparable to or better than that of other models derived from satellite altimetry. The new CryoSat-2 digital elevation model of Antarctica will be made freely available.
Paul J. Valdes, Edward Armstrong, Marcus P. S. Badger, Catherine D. Bradshaw, Fran Bragg, Michel Crucifix, Taraka Davies-Barnard, Jonathan J. Day, Alex Farnsworth, Chris Gordon, Peter O. Hopcroft, Alan T. Kennedy, Natalie S. Lord, Dan J. Lunt, Alice Marzocchi, Louise M. Parry, Vicky Pope, William H. G. Roberts, Emma J. Stone, Gregory J. L. Tourte, and Jonny H. T. Williams
Geosci. Model Dev., 10, 3715–3743, https://doi.org/10.5194/gmd-10-3715-2017, https://doi.org/10.5194/gmd-10-3715-2017, 2017
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In this paper we describe the family of climate models used by the BRIDGE research group at the University of Bristol as well as by various other institutions. These models are based on the UK Met Office HadCM3 models and here we describe the various modifications which have been made as well as the key features of a number of configurations in use.
M. Dolores Pérez-Hernández, Alonso Hernández-Guerra, Isis Comas-Rodríguez, Verónica M. Benítez-Barrios, Eugenio Fraile-Nuez, Josep L. Pelegrí, and Alberto C. Naveira Garabato
Ocean Sci., 13, 577–587, https://doi.org/10.5194/os-13-577-2017, https://doi.org/10.5194/os-13-577-2017, 2017
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The decadal differences between the ALBATROSS (April 1999) and MOC2-Austral (February 2010) hydrographic cruises are analyzed. Changes in the intermediate water masses beneath seem to be very sensitive to the wind conditions existing in their formation area. The Subantarctic Front is wider and weaker in 2010 than in 1999, while the Polar Front remains in the same position and strengthens.
A. Marzocchi, D. J. Lunt, R. Flecker, C. D. Bradshaw, A. Farnsworth, and F. J. Hilgen
Clim. Past, 11, 1271–1295, https://doi.org/10.5194/cp-11-1271-2015, https://doi.org/10.5194/cp-11-1271-2015, 2015
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This paper investigates the climatic response to orbital forcing through the analysis of an ensemble of simulations covering a late Miocene precession cycle. Including orbital variability in our model–data comparison reduces the mismatch between the proxy record and model output. Our results indicate that ignoring orbital variability could lead to miscorrelations in proxy reconstructions. The North African summer monsoon's sensitivity is high to orbits, moderate to paleogeography and low to CO2.
Related subject area
Approach: Remote Sensing | Properties and processes: Climate and modes of variability
Tracking Marine Heatwaves in the Balearic Sea: Temperature Trends and the Role of Detection Methods
Investigating the long-term variability of the Red Sea marine heatwaves and their relationship to different climate modes: focus on 2010 events in the northern basin
Blanca Fernández-Álvarez, Bàrbara Barceló-Llull, and Ananda Pascual
EGUsphere, https://doi.org/10.5194/egusphere-2024-4065, https://doi.org/10.5194/egusphere-2024-4065, 2025
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Marine heatwaves (MHWs) standard detection method uses a fixed baseline, showing rising MHW frequency and intensity due to global warming, eventually reaching saturation. To address this, alternative approaches separate long-term warming from extreme events. Here we compare two in the Balearic Sea: moving baseline and detrending data. We found a warming trend of 0.036 °C/year, with major MHWs in 2003 and 2022 identified by all methods. Only the fixed baseline shows rising MHW frequency.
Manal Hamdeno, Aida Alvera-Azcárate, George Krokos, and Ibrahim Hoteit
Ocean Sci., 20, 1087–1107, https://doi.org/10.5194/os-20-1087-2024, https://doi.org/10.5194/os-20-1087-2024, 2024
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Our study focuses on the characteristics of MHWs in the Red Sea during the last 4 decades. Using satellite-derived sea surface temperatures (SSTs), we found a clear warming trend in the Red Sea since 1994, which has intensified significantly since 2016. This SST rise was associated with an increase in the frequency and days of MHWs. In addition, a correlation was found between the frequency of MHWs and some climate modes, which was more pronounced in some years of the study period.
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Short summary
Heat and freshwater fluxes in the Southern Ocean mediate global ocean circulation and abyssal ventilation. These fluxes manifest as changes in steric height: sea level anomalies from changes in ocean density. We compute the steric height anomaly of the Southern Ocean using satellite data and validate it against in situ observations. We analyse trends and variability in steric height, drawing links to climate variability, and discuss the effectiveness of the method, highlighting issues with its application.
Heat and freshwater fluxes in the Southern Ocean mediate global ocean circulation and abyssal...
