Articles | Volume 28, issue 1
https://doi.org/10.5194/npg-28-43-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/npg-28-43-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 Jan 2021
Research article |
| 19 Jan 2021
| 19 Jan 2021
Ordering of trajectories reveals hierarchical finite-time coherent sets in Lagrangian particle data: detecting Agulhas rings in the South Atlantic Ocean
Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
Centre for Complex Systems Studies, Utrecht University, Utrecht, the Netherlands
Christian Kehl
Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
Henk A. Dijkstra
Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
Centre for Complex Systems Studies, Utrecht University, Utrecht, the Netherlands
Erik van Sebille
Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, the Netherlands
Centre for Complex Systems Studies, Utrecht University, Utrecht, the Netherlands
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Meike F. Bos, Irina I. Rypina, Larry J. Pratt, and Erik van Sebille
EGUsphere, https://doi.org/10.5194/egusphere-2026-64, https://doi.org/10.5194/egusphere-2026-64, 2026
This preprint is open for discussion and under review for Ocean Science (OS).
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Macroplastic items in the ocean can move differently than the water surrounding them, because their size and density are different than that of water. We investigate how to implement this effect for macroplastic items in simulations in the North West European Shelf region. For this region we find that the large drag force makes the macroplastics trajectories very closely follow the water itself, meaning that simulating macroplastic is simpler than previously expected.
Erik van Sebille, Celine Weel, Rens Vliegenthart, and Mark Bos
Geosci. Commun., 9, 69–86, https://doi.org/10.5194/gc-9-69-2026, https://doi.org/10.5194/gc-9-69-2026, 2026
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Many climate scientists intuitively fear their credibility decreases when they engage in advocacy. We find that the opposite is the case. By surveying almost 1000 Dutch adults, we found that the credibility of a fictional climate scientists who wrote an article about the greening of gardens was higher when that text included advocacy statements, compared to when it was
neutral. This is because personalization increases the goodwill of readers for the academic who writes a text.
Jimena Medina-Rubio, Madlene Nussbaum, Ton S. van den Bremer, and Erik van Sebille
Ocean Sci., 22, 49–74, https://doi.org/10.5194/os-22-49-2026, https://doi.org/10.5194/os-22-49-2026, 2026
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We study how tides, wind, and waves interact at the ocean surface by tracking ultra-thin drifters released in the southern North Sea for two months. Using model data together with data-driven machine learning models, we determine the relative contribution of each forcing mechanism in driving the drifters' velocity and improve the prediction of their trajectories. We also test the generalisability of this method by applying it to the same drifters in the Tyrrhenian Sea.
Marc Emanuel Schneiter, Rolf Hut, and Erik Van Sebille
EGUsphere, https://doi.org/10.5194/egusphere-2025-6170, https://doi.org/10.5194/egusphere-2025-6170, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
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We study land-water transitions of 24 small floating position-trackers that approximately mimic floating plastic litter. We describe how to automatically identify such transitions from recorded tracks, and we characterize our observations with respect to sea and wind conditions. The insights can be integrated in model simulations and used for the planning of beach cleanups. We released the trackers in the Wadden Sea, a shallow body of water that is strongly influenced by tides and wind.
René M. van Westen, Elian Vanderborght, and Henk A. Dijkstra
Earth Syst. Dynam., 16, 2063–2085, https://doi.org/10.5194/esd-16-2063-2025, https://doi.org/10.5194/esd-16-2063-2025, 2025
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The Atlantic Meridional Overturning Circulation (AMOC) is a tipping element in the fully-coupled Community Earth System Model (CESM). Under varying freshwater flux forcing parameters or climate change, the AMOC may collapse from a relatively strong state to a substantially weaker state. It is important to understand the dynamics of the AMOC collapse in the CESM. We show that the stability of the AMOC in the CESM is controlled by only a few feedback processes.
Swinda K. J. Falkena, Henk A. Dijkstra, and Anna S. von der Heydt
Earth Syst. Dynam., 16, 1833–1844, https://doi.org/10.5194/esd-16-1833-2025, https://doi.org/10.5194/esd-16-1833-2025, 2025
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The subpolar gyre is a wind-driven circulation in the North Atlantic Ocean that enables the mixing of water between the surface and deeper layers. We investigate the interactions between the strength of the gyre circulation, salinity, temperature, and mixing in climate models. We find that most models capture an increase in salinity or a decrease in temperature, leading to mixing. However, the feedback from the density in the gyre centre to the strength of its circulation is poorly represented.
Claudio M. Pierard, Siren Rühs, Laura Gómez-Navarro, Michael Charles Denes, Florian Meirer, Thierry Penduff, and Erik van Sebille
Nonlin. Processes Geophys., 32, 411–438, https://doi.org/10.5194/npg-32-411-2025, https://doi.org/10.5194/npg-32-411-2025, 2025
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Particle-tracking simulations compute how ocean currents transport material. However, initializing these simulations is often ad hoc. Here, we explore how two different strategies (releasing particles over space or over time) compare. Specifically, we compare the variability in particle trajectories to the variability of particles computed in a 50-member ensemble simulation. We find that releasing the particles over 20 weeks gives variability that is most like that in the ensemble.
Aike Vonk, Mark Bos, and Erik van Sebille
Geosci. Commun., 8, 297–317, https://doi.org/10.5194/gc-8-297-2025, https://doi.org/10.5194/gc-8-297-2025, 2025
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Research institutes communicate scientific findings through press releases, which journalists use to write news articles. We examined how journalists use content from press releases about ocean plastic research. Our findings show that they closely follow the press releases story, primarily quoting involved scientists without seeking external perspectives. Causing the focus to stay on researchers, personalizing science rather than addressing the broader societal dimensions of plastic pollution.
Sina Loriani, Yevgeny Aksenov, David I. Armstrong McKay, Govindasamy Bala, Andreas Born, Cristiano Mazur Chiessi, Henk A. Dijkstra, Jonathan F. Donges, Sybren Drijfhout, Matthew H. England, Alexey V. Fedorov, Laura C. Jackson, Kai Kornhuber, Gabriele Messori, Francesco S. R. Pausata, Stefanie Rynders, Jean-Baptiste Sallée, Bablu Sinha, Steven C. Sherwood, Didier Swingedouw, and Thejna Tharammal
Earth Syst. Dynam., 16, 1611–1653, https://doi.org/10.5194/esd-16-1611-2025, https://doi.org/10.5194/esd-16-1611-2025, 2025
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In this work, we draw on palaeo-records, observations, and modelling studies to review tipping points in the ocean overturning circulations, monsoon systems, and global atmospheric circulations. We find indications for tipping in the ocean overturning circulations and the West African monsoon, with potentially severe impacts on the Earth system and humans. Tipping in the other considered systems is regarded as conceivable but is currently not sufficiently supported by evidence.
Aurora Faure Ragani and Henk A. Dijkstra
Earth Syst. Dynam., 16, 1287–1301, https://doi.org/10.5194/esd-16-1287-2025, https://doi.org/10.5194/esd-16-1287-2025, 2025
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The Atlantic Meridional Overturning Circulation (AMOC) is sensitive to changing surface forcing conditions. Under future greenhouse gas emission reductions, it was shown in a conceptual model that it may be possible to avoid a collapse of the AMOC. Using a detailed global ocean model, we clarify the physics of the collapse and recovery behaviour of the AMOC. The potential to avoid an AMOC collapse is tightly linked to a delicate balance of salt fluxes in the northern North Atlantic.
Amber A. Boot and Henk A. Dijkstra
Earth Syst. Dynam., 16, 1221–1235, https://doi.org/10.5194/esd-16-1221-2025, https://doi.org/10.5194/esd-16-1221-2025, 2025
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The Atlantic Meridional Overturning Circulation (AMOC) is a tipping element in the Earth system that affects the global climate. We often use models to understand how the AMOC tips. However, these models are flawed. Here we study the effect of these flaws on the AMOC multistable regime in a climate model. We artificially add additional flaws to the model. We find that AMOC stability can be affected by such flaws, and a reduction in such flaws in climate models is therefore thought to be essential.
Francesco Guardamagna, Claudia Wieners, and Henk A. Dijkstra
Nonlin. Processes Geophys., 32, 201–224, https://doi.org/10.5194/npg-32-201-2025, https://doi.org/10.5194/npg-32-201-2025, 2025
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Artificial intelligence (AI) has recently shown promising results in ENSO (El Niño–Southern Oscillation) forecasting, outperforming traditional models. Yet AI models deliver accurate predictions without showing the underlying mechanisms. Our study examines a specific AI model, the reservoir computer (RC). Our results show that the RC is less sensitive to initial perturbations than the traditional Zebiak–Cane (ZC) model. This reduced sensitivity can explain the RC's superior skills.
Vesna Bertoncelj, Furu Mienis, Paolo Stocchi, and Erik van Sebille
Ocean Sci., 21, 945–964, https://doi.org/10.5194/os-21-945-2025, https://doi.org/10.5194/os-21-945-2025, 2025
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This study explores ocean currents around Curaçao and how land-derived substances like pollutants and nutrients travel in the water. Most substances move northwest, following the main current, but at times, ocean eddies spread them in other directions. This movement may link polluted areas to pristine coral reefs, impacting marine ecosystems. Understanding these patterns helps inform conservation and pollution management around Curaçao.
Woosok Moon, Seung Pyo Lee, Elian Vanderborght, Georgy Manucharyan, and Henk Dijkstra
EGUsphere, https://doi.org/10.5194/egusphere-2025-1004, https://doi.org/10.5194/egusphere-2025-1004, 2025
Preprint archived
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As the climate warms, extreme weather is becoming more frequent in mid-latitudes. A key factor is the jet stream, shaped by atmospheric waves that influence wind and storm patterns. This study presents a simplified model showing how swirling air currents (eddies) maintain the jet stream and impact weather. As global warming alters these patterns, this research helps improve predictions of future weather changes.
Nieske Vergunst, Tugce Varol, and Erik van Sebille
Geosci. Commun., 8, 67–80, https://doi.org/10.5194/gc-8-67-2025, https://doi.org/10.5194/gc-8-67-2025, 2025
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We developed and evaluated a board game about sea level rise to engage young adults. We found that the game positively influenced participants' perceptions of their impact on sea level rise, regardless of their prior familiarity with science. This study suggests that interactive and relatable activities can effectively engage audiences on climate issues, highlighting the potential for similar approaches in public science communication.
Mark V. Elbertsen, Erik van Sebille, and Peter K. Bijl
Clim. Past, 21, 441–464, https://doi.org/10.5194/cp-21-441-2025, https://doi.org/10.5194/cp-21-441-2025, 2025
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This work verifies the remarkable finds of late Eocene Antarctic-sourced iceberg-rafted debris on the South Orkney Microcontinent. We find that these icebergs must have been on the larger end of the size scale compared to today’s icebergs due to faster melting in the warmer Eocene climate. The study was performed using a high-resolution model in which individual icebergs were followed through time.
Bouke Biemond, Wouter M. Kranenburg, Ymkje Huismans, Huib E. de Swart, and Henk A. Dijkstra
Ocean Sci., 21, 261–281, https://doi.org/10.5194/os-21-261-2025, https://doi.org/10.5194/os-21-261-2025, 2025
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We study salinity in estuaries consisting of a network of channels. To this end, we develop a model that computes the flow and salinity in such systems. We use the model to quantify the mechanisms by which salt is transported into estuarine networks, the response to changes in river discharge, and the impact of depth changes. Results show that when changing the depth of channels, the effects on salt intrusion into other channels in the network can be larger than the effect on the channel itself.
Siren Rühs, Ton van den Bremer, Emanuela Clementi, Michael C. Denes, Aimie Moulin, and Erik van Sebille
Ocean Sci., 21, 217–240, https://doi.org/10.5194/os-21-217-2025, https://doi.org/10.5194/os-21-217-2025, 2025
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Simulating the transport of floating particles on the ocean surface is crucial for solving many societal issues. Here, we investigate how the representation of wind-generated surface waves impacts particle transport simulations. We find that different wave-driven processes can alter transport patterns and that commonly adopted approximations are not always adequate. This suggests that ideally coupled ocean–wave models should be used for surface particle transport simulations.
Amber A. Boot and Henk A. Dijkstra
Earth Syst. Dynam., 16, 115–150, https://doi.org/10.5194/esd-16-115-2025, https://doi.org/10.5194/esd-16-115-2025, 2025
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The ocean is forced at the surface by a heat flux and a freshwater flux. This noise can influence long-term ocean variability and large-scale circulation. Here we study noise characteristics in reanalysis data for these fluxes. We try to capture the noise characteristics by using several noise models and compare these to state-of-the-art climate models. A pointwise noise model performs better than the climate models and can be used as forcing in ocean-only models.
Amber A. Boot, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 15, 1567–1590, https://doi.org/10.5194/esd-15-1567-2024, https://doi.org/10.5194/esd-15-1567-2024, 2024
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We investigate the multiple equilibria window (MEW) of the Atlantic Meridional Overturning Circulation (AMOC) within a box model. We find that increasing the total carbon content of the system widens the MEW of the AMOC. The important mechanisms at play are the balance between the source and sink of carbon and the sensitivity of the AMOC to freshwater forcing over the Atlantic Ocean. Our results suggest that changes in the marine carbon cycle can influence AMOC stability in future climates.
Anna Leerink, Mark Bos, Daan Reijnders, and Erik van Sebille
Geosci. Commun., 7, 201–214, https://doi.org/10.5194/gc-7-201-2024, https://doi.org/10.5194/gc-7-201-2024, 2024
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Climate scientists who communicate to a broad audience may be reluctant to write in a more personal style, as they assume that it hurts their credibility. To test this assumption, we asked 100 Dutch people to rate the credibility of a climate scientist. We varied how the author of the article addressed the reader and found that the degree of personalization did not have a measurable impact on the credibility of the author. Thus, we conclude that personalization may not hurt credibility.
Arthur Merlijn Oldeman, Michiel L. J. Baatsen, Anna S. von der Heydt, Frank M. Selten, and Henk A. Dijkstra
Earth Syst. Dynam., 15, 1037–1054, https://doi.org/10.5194/esd-15-1037-2024, https://doi.org/10.5194/esd-15-1037-2024, 2024
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We might be able to constrain uncertainty in future climate projections by investigating variations in the climate of the past. In this study, we investigate the interactions of climate variability between the tropical Pacific (El Niño) and the North Pacific in a warm past climate – the mid-Pliocene, a period roughly 3 million years ago. Using model simulations, we find that, although the variability in El Niño was reduced, the variability in the North Pacific atmosphere was not.
Sacha Sinet, Peter Ashwin, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 15, 859–873, https://doi.org/10.5194/esd-15-859-2024, https://doi.org/10.5194/esd-15-859-2024, 2024
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Some components of the Earth system may irreversibly collapse under global warming. Among them, the Atlantic Meridional Overturning Circulation (AMOC), the Greenland Ice Sheet, and West Antarctica Ice Sheet are of utmost importance for maintaining the present-day climate. In a simplified model, we show that both the rate of ice melting and the natural variability linked to freshwater fluxes over the Atlantic Ocean drastically affect how an ice sheet collapse impacts the AMOC stability.
Julia E. Weiffenbach, Henk A. Dijkstra, Anna S. von der Heydt, Ayako Abe-Ouchi, Wing-Le Chan, Deepak Chandan, Ran Feng, Alan M. Haywood, Stephen J. Hunter, Xiangyu Li, Bette L. Otto-Bliesner, W. Richard Peltier, Christian Stepanek, Ning Tan, Julia C. Tindall, and Zhongshi Zhang
Clim. Past, 20, 1067–1086, https://doi.org/10.5194/cp-20-1067-2024, https://doi.org/10.5194/cp-20-1067-2024, 2024
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Elevated atmospheric CO2 concentrations and a smaller Antarctic Ice Sheet during the mid-Pliocene (~ 3 million years ago) cause the Southern Ocean surface to become fresher and warmer, which affects the global ocean circulation. The CO2 concentration and the smaller Antarctic Ice Sheet both have a similar and approximately equal impact on the Southern Ocean. The conditions of the Southern Ocean in the mid-Pliocene could therefore be analogous to those in a future climate with smaller ice sheets.
Frances Wijnen, Madelijn Strick, Mark Bos, and Erik van Sebille
Geosci. Commun., 7, 91–100, https://doi.org/10.5194/gc-7-91-2024, https://doi.org/10.5194/gc-7-91-2024, 2024
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Climate scientists are urged to communicate climate science; there is very little evidence about what types of communication work well for which audiences. We have performed a systematic literature review to analyze what is known about the efficacy of climate communication by scientists. While we have found more than 60 articles in the last 10 years about climate communication activities by scientists, only 7 of these included some form of evaluation of the impact of the activity.
René M. van Westen and Henk A. Dijkstra
Ocean Sci., 20, 549–567, https://doi.org/10.5194/os-20-549-2024, https://doi.org/10.5194/os-20-549-2024, 2024
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The Atlantic Meridional Overturning Circulation (AMOC) is an important component in the global climate system. Observations of the present-day AMOC indicate that it may weaken or collapse under global warming, with profound disruptive effects on future climate. However, AMOC weakening is not correctly represented because an important feedback is underestimated due to biases in the Atlantic's freshwater budget. Here we address these biases in several state-of-the-art climate model simulations.
Arthur Merlijn Oldeman, Michiel L. J. Baatsen, Anna S. von der Heydt, Aarnout J. van Delden, and Henk A. Dijkstra
Weather Clim. Dynam., 5, 395–417, https://doi.org/10.5194/wcd-5-395-2024, https://doi.org/10.5194/wcd-5-395-2024, 2024
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The mid-Pliocene, a geological period around 3 million years ago, is sometimes considered the best analogue for near-future climate. It saw similar CO2 concentrations to the present-day but also a slightly different geography. In this study, we use climate model simulations and find that the Northern Hemisphere winter responds very differently to increased CO2 or to the mid-Pliocene geography. Our results weaken the potential of the mid-Pliocene as a future climate analogue.
Philippe F. V. W. Frankemölle, Peter D. Nooteboom, Joe Scutt Phillips, Lauriane Escalle, Simon Nicol, and Erik van Sebille
Ocean Sci., 20, 31–41, https://doi.org/10.5194/os-20-31-2024, https://doi.org/10.5194/os-20-31-2024, 2024
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Tuna fisheries in the Pacific often use drifting fish aggregating devices (dFADs) to attract fish that are advected by subsurface flow through underwater appendages. Using a particle advection model, we find that virtual particles advected by surface flow are displaced farther than virtual dFADs. We find a relation between El Niño–Southern Oscillation and circular motion in some areas, influencing dFAD densities. This information helps us to understand processes that drive dFAD distribution.
Michiel Baatsen, Peter Bijl, Anna von der Heydt, Appy Sluijs, and Henk Dijkstra
Clim. Past, 20, 77–90, https://doi.org/10.5194/cp-20-77-2024, https://doi.org/10.5194/cp-20-77-2024, 2024
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This work introduces the possibility and consequences of monsoons on Antarctica in the warm Eocene climate. We suggest that such a monsoonal climate can be important to understand conditions in Antarctica prior to large-scale glaciation. We can explain seemingly contradictory indications of ice and vegetation on the continent through regional variability. In addition, we provide a new mechanism through which most of Antarctica remained ice-free through a wide range of global climatic changes.
Tor Nordam, Ruben Kristiansen, Raymond Nepstad, Erik van Sebille, and Andy M. Booth
Geosci. Model Dev., 16, 5339–5363, https://doi.org/10.5194/gmd-16-5339-2023, https://doi.org/10.5194/gmd-16-5339-2023, 2023
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We describe and compare two common methods, Eulerian and Lagrangian models, used to simulate the vertical transport of material in the ocean. They both solve the same transport problems but use different approaches for representing the underlying equations on the computer. The main focus of our study is on the numerical accuracy of the two approaches. Our results should be useful for other researchers creating or using these types of transport models.
Valérian Jacques-Dumas, René M. van Westen, Freddy Bouchet, and Henk A. Dijkstra
Nonlin. Processes Geophys., 30, 195–216, https://doi.org/10.5194/npg-30-195-2023, https://doi.org/10.5194/npg-30-195-2023, 2023
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Computing the probability of occurrence of rare events is relevant because of their high impact but also difficult due to the lack of data. Rare event algorithms are designed for that task, but their efficiency relies on a score function that is hard to compute. We compare four methods that compute this function from data and measure their performance to assess which one would be best suited to be applied to a climate model. We find neural networks to be most robust and flexible for this task.
Julia E. Weiffenbach, Michiel L. J. Baatsen, Henk A. Dijkstra, Anna S. von der Heydt, Ayako Abe-Ouchi, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Mark A. Chandler, Camille Contoux, Ran Feng, Chuncheng Guo, Zixuan Han, Alan M. Haywood, Qiang Li, Xiangyu Li, Gerrit Lohmann, Daniel J. Lunt, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Gilles Ramstein, Linda E. Sohl, Christian Stepanek, Ning Tan, Julia C. Tindall, Charles J. R. Williams, Qiong Zhang, and Zhongshi Zhang
Clim. Past, 19, 61–85, https://doi.org/10.5194/cp-19-61-2023, https://doi.org/10.5194/cp-19-61-2023, 2023
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We study the behavior of the Atlantic Meridional Overturning Circulation (AMOC) in the mid-Pliocene. The mid-Pliocene was about 3 million years ago and had a similar CO2 concentration to today. We show that the stronger AMOC during this period relates to changes in geography and that this has a significant influence on ocean temperatures and heat transported northwards by the Atlantic Ocean. Understanding the behavior of the mid-Pliocene AMOC can help us to learn more about our future climate.
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.
Amber Boot, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 13, 1041–1058, https://doi.org/10.5194/esd-13-1041-2022, https://doi.org/10.5194/esd-13-1041-2022, 2022
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Atmospheric pCO2 of the past shows large variability on different timescales. We focus on the effect of the strength of Atlantic Meridional Overturning Circulation (AMOC) on this variability and on the AMOC–pCO2 relationship. We find that climatic boundary conditions and the representation of biology in our model are most important for this relationship. Under certain conditions, we find internal oscillations, which can be relevant for atmospheric pCO2 variability during glacial cycles.
Reint Fischer, Delphine Lobelle, Merel Kooi, Albert Koelmans, Victor Onink, Charlotte Laufkötter, Linda Amaral-Zettler, Andrew Yool, and Erik van Sebille
Biogeosciences, 19, 2211–2234, https://doi.org/10.5194/bg-19-2211-2022, https://doi.org/10.5194/bg-19-2211-2022, 2022
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Since current estimates show that only about 1 % of the all plastic that enters the ocean is floating at the surface, we look at subsurface processes that can cause vertical movement of (micro)plastic. We investigate how modelled algal attachment and the ocean's vertical movement can cause particles to sink and oscillate in the open ocean. Particles can sink to depths of > 5000 m in regions with high wind intensity and mainly remain close to the surface with low winds and biological activity.
Victor Onink, Erik van Sebille, and Charlotte Laufkötter
Geosci. Model Dev., 15, 1995–2012, https://doi.org/10.5194/gmd-15-1995-2022, https://doi.org/10.5194/gmd-15-1995-2022, 2022
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Turbulent mixing is a vital process in 3D modeling of particle transport in the ocean. However, since turbulence occurs on very short spatial scales and timescales, large-scale ocean models generally have highly simplified turbulence representations. We have developed parametrizations for the vertical turbulent transport of buoyant particles that can be easily applied in a large-scale particle tracking model. The predicted vertical concentration profiles match microplastic observations well.
Mikael L. A. Kaandorp, Stefanie L. Ypma, Marijke Boonstra, Henk A. Dijkstra, and Erik van Sebille
Ocean Sci., 18, 269–293, https://doi.org/10.5194/os-18-269-2022, https://doi.org/10.5194/os-18-269-2022, 2022
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A large amount of marine litter, such as plastics, is located on or around beaches. Both the total amount of this litter and its transport are poorly understood. We investigate this by training a machine learning model with data of cleanup efforts on Dutch beaches between 2014 and 2019, obtained by about 14 000 volunteers. We find that Dutch beaches contain up to 30 000 kg of litter, largely depending on tides, oceanic transport, and how exposed the beaches are.
Peter D. Nooteboom, Peter K. Bijl, Christian Kehl, Erik van Sebille, Martin Ziegler, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 13, 357–371, https://doi.org/10.5194/esd-13-357-2022, https://doi.org/10.5194/esd-13-357-2022, 2022
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Having descended through the water column, microplankton in ocean sediments represents the ocean surface environment and is used as an archive of past and present surface oceanographic conditions. However, this microplankton is advected by turbulent ocean currents during its sinking journey. We use simulations of sinking particles to define ocean bottom provinces and detect these provinces in datasets of sedimentary microplankton, which has implications for palaeoclimate reconstructions.
Arthur M. Oldeman, Michiel L. J. Baatsen, Anna S. von der Heydt, Henk A. Dijkstra, Julia C. Tindall, Ayako Abe-Ouchi, Alice R. Booth, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Mark A. Chandler, Camille Contoux, Ran Feng, Chuncheng Guo, Alan M. Haywood, Stephen J. Hunter, Youichi Kamae, Qiang Li, Xiangyu Li, Gerrit Lohmann, Daniel J. Lunt, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Gabriel M. Pontes, Gilles Ramstein, Linda E. Sohl, Christian Stepanek, Ning Tan, Qiong Zhang, Zhongshi Zhang, Ilana Wainer, and Charles J. R. Williams
Clim. Past, 17, 2427–2450, https://doi.org/10.5194/cp-17-2427-2021, https://doi.org/10.5194/cp-17-2427-2021, 2021
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In this work, we have studied the behaviour of El Niño events in the mid-Pliocene, a period of around 3 million years ago, using a collection of 17 climate models. It is an interesting period to study, as it saw similar atmospheric carbon dioxide levels to the present day. We find that the El Niño events were less strong in the mid-Pliocene simulations, when compared to pre-industrial climate. Our results could help to interpret El Niño behaviour in future climate projections.
André Jüling, Anna von der Heydt, and Henk A. Dijkstra
Ocean Sci., 17, 1251–1271, https://doi.org/10.5194/os-17-1251-2021, https://doi.org/10.5194/os-17-1251-2021, 2021
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On top of forced changes such as human-caused global warming, unforced climate variability exists. Most multidecadal variability (MV) involves the oceans, but current climate models use non-turbulent, coarse-resolution oceans. We investigate the effect of resolving important turbulent ocean features on MV. We find that ocean heat content, ocean–atmosphere heat flux, and global mean surface temperature MV is more pronounced in the higher-resolution model relative to higher-frequency variability.
Johannes Lohmann, Daniele Castellana, Peter D. Ditlevsen, and Henk A. Dijkstra
Earth Syst. Dynam., 12, 819–835, https://doi.org/10.5194/esd-12-819-2021, https://doi.org/10.5194/esd-12-819-2021, 2021
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Tipping of one climate subsystem could trigger a cascade of subsequent tipping points and even global-scale climate tipping. Sequential shifts of atmosphere, sea ice and ocean have been recorded in proxy archives of past climate change. Based on this we propose a conceptual model for abrupt climate changes of the last glacial. Here, rate-induced tipping enables tipping cascades in systems with relatively weak coupling. An early warning signal is proposed that may detect such a tipping.
C. Kehl, R. P. B. Fischer, and E. van Sebille
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-4-2021, 217–224, https://doi.org/10.5194/isprs-annals-V-4-2021-217-2021, https://doi.org/10.5194/isprs-annals-V-4-2021-217-2021, 2021
André Jüling, Xun Zhang, Daniele Castellana, Anna S. von der Heydt, and Henk A. Dijkstra
Ocean Sci., 17, 729–754, https://doi.org/10.5194/os-17-729-2021, https://doi.org/10.5194/os-17-729-2021, 2021
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We investigate how the freshwater budget of the Atlantic changes under climate change, which has implications for the stability of the Atlantic Meridional Overturning Circulation. We compare the effect of ocean model resolution in a climate model and find many similarities between the simulations, enhancing trust in the current generation of climate models. However, ocean biases are reduced in the strongly eddying simulation, and significant local freshwater budget differences exist.
Rebeca de la Fuente, Gábor Drótos, Emilio Hernández-García, Cristóbal López, and Erik van Sebille
Ocean Sci., 17, 431–453, https://doi.org/10.5194/os-17-431-2021, https://doi.org/10.5194/os-17-431-2021, 2021
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Plastic pollution is a major environmental issue affecting the oceans. The number of floating and sedimented pieces has been quantified by several studies. But their abundance in the water column remains mostly unknown. To fill this gap we model the dynamics of a particular type of particle, rigid microplastics sinking rapidly in open sea in the Mediterranean. We find they represent a small but appreciable fraction of the total sea plastic and discuss characteristics of their sinking motion.
Pascal Wang, Daniele Castellana, and Henk A. Dijkstra
Nonlin. Processes Geophys., 28, 135–151, https://doi.org/10.5194/npg-28-135-2021, https://doi.org/10.5194/npg-28-135-2021, 2021
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This paper proposes two improvements to the use of Trajectory-Adaptive Multilevel Sampling, a rare-event algorithm which computes noise-induced transition probabilities. The first improvement uses locally linearised dynamics in order to reduce the arbitrariness associated with defining what constitutes a transition. The second improvement uses empirical transition paths accumulated at high noise in order to formulate the score function which determines the performance of the algorithm.
Amber Boot, René M. van Westen, and Henk A. Dijkstra
Ocean Sci., 17, 335–350, https://doi.org/10.5194/os-17-335-2021, https://doi.org/10.5194/os-17-335-2021, 2021
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The Maud Rise polynya is a hole in the sea ice surrounding Antarctica that occurs during winter. It appeared in 2016 and 2017. Our study concludes that heat and salt accumulation around 1000 m depth are likely to be important for polynya formation. The heat is mixed upward to the surface where it is able to melt the sea ice and, thus, create a polynya. How often the polynya forms depends largely on the variation in the time of the heat and salt accumulation.
Cited articles
Beron-Vera, F. J., Wang, Y., Olascoaga, M. J., Goni, G. J., and Haller, G.:
Objective Detection of Oceanic Eddies and the Agulhas Leakage, J.
Phys. Oceanogr., 43, 1426–1438,
https://doi.org/10.1175/JPO-D-12-0171.1, 2013. a, b
Bickley, W.: LXXIII. The plane jet, The London, Edinburgh, and Dublin
Philosophical Magazine and Journal of Science, 23, 727–731,
https://doi.org/10.1080/14786443708561847, 1937. a
Brach, L., Deixonne, P., Bernard, M. F., Durand, E., Desjean, M. C., Perez, E.,
van Sebille, E., and ter Halle, A.: Anticyclonic eddies increase
accumulation of microplastic in the North Atlantic subtropical gyre, Marine
Pollution Bulletin, 126, 191–196,
https://doi.org/10.1016/j.marpolbul.2017.10.077, 2018. a
del Castillo-Negrete, D. and Morrison, P.: Chaotic transport by Rossby waves in
shear flow, Phys. Fluids A, 5, 948–965,
https://doi.org/10.1063/1.858639, 1993. a
Delandmeter, P. and van Sebille, E.: The Parcels v2.0 Lagrangian framework: new field interpolation schemes, Geosci. Model Dev., 12, 3571–3584, https://doi.org/10.5194/gmd-12-3571-2019, 2019. a
Dencausse, G., Arhan, M., and Speich, S.: Routes of Agulhas rings in the
southeastern Cape Basin, Deep-Sea Res. Pt. I, 57, 1406–1421, https://doi.org/10.1016/j.dsr.2010.07.008,
2010. a
Dong, C., McWilliams, J. C., Liu, Y., and Chen, D.: Global heat and salt
transports by eddy movement, Nature Commun., 5, 3294,
https://doi.org/10.1038/ncomms4294, 2014. a
Dussin, R., Barnier, B., and Brodeau, L.: The making of Drakkar forcing set
DFS5, Tech. rep., LGGE, Grenoble, France, 2016. a
Fouss, F., Saerens, M., and Shimbo, M.: Algorithms and models for network data
and link analysis, Cambridge University Press, Cambridge, https://doi.org/10.1017/CBO9781316418321, 2016. a, b
Froyland, G., Santitissadeekorn, N., and Monahan, A.: Transport in
time-dependent dynamical systems: Finite-time coherent sets, Chaos: An
Interdisciplinary J. Nonlinear Sci., 20, 043116,
https://doi.org/10.1063/1.3502450, 2010. a, b
Froyland, G., Stuart, R. M., and van Sebille, E.: How well-connected is the
surface of the global ocean?, Chaos: An Interdisciplinary J.
Nonlinear Sci., 24, 033126, https://doi.org/10.1063/1.4892530,
2014. a
Froyland, G., Horenkamp, C., Rossi, V., and van Sebille, E.: Studying an
Agulhas ring's long-term pathway and decay with finite-time coherent sets,
Chaos: An Interdisciplinary J. Nonlinear Sci., 25, 083119,
https://doi.org/10.1063/1.4927830, 2015. a
Froyland, G., Rock, C. P., and Sakellariou, K.: Sparse eigenbasis
approximation: Multiple feature extraction across spatiotemporal scales with
application to coherent set identification, Communications in Nonlinear
Science and Numerical Simulation, 77, 81–107,
https://doi.org/10.1016/j.cnsns.2019.04.012, 2019. a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q
Hadjighasem, A., Farazmand, M., Blazevski, D., Froyland, G., and Haller, G.: A
critical comparison of Lagrangian methods for coherent structure detection,
Chaos: An Interdisciplinary J. Nonlinear Sci., 27, 053104,
https://doi.org/10.1063/1.4982720, 2017. a, b, c, d
Haller, G. and Beron-Vera, F. J.: Coherent Lagrangian vortices: The black
holes of turbulence, J. Fluid Mech., 731,
https://doi.org/10.1017/jfm.2013.391, 2013. a
Lange, M. and van Sebille, E.: Parcels v0.9: prototyping a Lagrangian ocean analysis framework for the petascale age, Geosci. Model Dev., 10, 4175–4186, https://doi.org/10.5194/gmd-10-4175-2017, 2017. a
Ma, T. and Bollt, E. M.: Relatively Coherent Sets as a Hierarchical Partition
Method, Int. J. Bifurcat.Chaos, 23, 1330026,
https://doi.org/10.1142/S0218127413300267, 2013. a, b
Madec, G.: NEMO ocean engine, Note du Pôle de modélisation, No
27, 2008. a
Roweis, S. T. and Saul, L. K.: Nonlinear Dimensionality Reduction by Locally
Linear Embedding, Science, 290, 2323–2326,
https://doi.org/10.1126/science.290.5500.2323, 2000. a
Schouten, M. W., de Ruijter, W. P. M., van Leeuwen, P. J., and Lutjeharms, J.
R. E.: Translation, decay and splitting of Agulhas rings in the southeastern
Atlantic Ocean, J. Geophys. Res.-Oceans, 105,
21913–21925, https://doi.org/10.1029/1999jc000046, 2000. a
Shi, J. and Malik, J.: Normalized cuts and image segmentation, IEEE
Transactions on Pattern Analysis and Machine Intelligence, 22, 888–905,
https://doi.org/10.1109/34.868688, 2000. a, b
Tarshish, N., Abernathey, R., Zhang, C., Dufour, C. O., Frenger, I., and
Griffies, S. M.: Identifying Lagrangian coherent vortices in a mesoscale
ocean model, Ocean Model., 130, 15–28,
https://doi.org/10.1016/j.ocemod.2018.07.001, 2018.
a
van Sebille, E., Aliani, S., Law, K. L., Maximenko, N., Alsina, J. M.,
Bagaev, A., Bergmann, M., Chapron, B., Chubarenko, I., Cózar, A.,
Delandmeter, P., Egger, M., Fox-Kemper, B., Garaba, S. P., Goddijn-Murphy,
L., Hardesty, B. D., Hoffman, M. J., Isobe, A., Jongedijk, C. E., Kaandorp,
M. L., Khatmullina, L., Koelmans, A. A., Kukulka, T., Laufkötter, C.,
Lebreton, L., Lobelle, D., Maes, C., Martinez-Vicente, V., Morales Maqueda,
M. A., Poulain-Zarcos, M., Rodríguez, E., Ryan, P. G., Shanks, A. L.,
Shim, W. J., Suaria, G., Thiel, M., Van Den Bremer, T. S., and Wichmann,
D.: The physical oceanography of the transport of floating marine debris,
Environ. Res. Lett., 15, 023003,
https://doi.org/10.1088/1748-9326/ab6d7d, 2020. a
Von Luxburg, U.: A Tutorial on spectral clustering, Stat.
Comput., 17, 395–416, https://doi.org/10.1007/s11222-007-9033-z,
2007. a, b
Wichmann, D.: Animation of finite-time coherent sets in the Agulhas region, Zenodo,
https://doi.org/10.5281/zenodo.4103741, 2020a. a
Wichmann, D.: Lagrangian particle dataset (2 years) for Agulhas region surface
flow, Zenodo, https://doi.org/10.5281/zenodo.3899942, 2020b. a, b
Wichmann, D.: OceanParcels/coherent_vortices_OPTICS: Release for publication of corresponding paper (Version v1.0), Zenodo, https://doi.org/10.5281/zenodo.4426287, 2021a. a
Wichmann, D.: OceanParcels/near_surface_microplastic: Release of code for near-surface microplastic simulations, Zenodo, https://doi.org/10.5281/zenodo.4426310, 2021b. a
Wichmann, D., Kehl, C., Dijkstra, H. A., and van Sebille, E.: Detecting flow features in scarce trajectory data using networks derived from symbolic itineraries: an application to surface drifters in the North Atlantic, Nonlin. Processes Geophys., 27, 501–518, https://doi.org/10.5194/npg-27-501-2020, 2020. a
Short summary
Fluid parcels transported in complicated flows often contain subsets of particles that stay close over finite time intervals. We propose a new method for detecting finite-time coherent sets based on the density-based clustering technique of ordering points to identify the clustering structure (OPTICS). Unlike previous methods, our method has an intrinsic notion of coherent sets at different spatial scales. OPTICS is readily implemented in the SciPy sklearn package, making it easy to use.
Fluid parcels transported in complicated flows often contain subsets of particles that stay...
