Articles | Volume 15, issue 4
https://doi.org/10.5194/os-15-1033-2019
© Author(s) 2019. 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-15-1033-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
02 Aug 2019
Research article |
| 02 Aug 2019
| 02 Aug 2019
Seasonal and regional variations of sinking in the subpolar North Atlantic from a high-resolution ocean model
Juan-Manuel Sayol
CORRESPONDING AUTHOR
Department of Hydraulic Engineering, Delft University of Technology, Delft, the Netherlands
Henk Dijkstra
Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, the Netherlands
Caroline Katsman
Department of Hydraulic Engineering, Delft University of Technology, Delft, the Netherlands
Related authors
Marcos García Sotillo, Emilio Garcia-Ladona, Alejandro Orfila, Pablo Rodríguez-Rubio, José Cristobal Maraver, Daniel Conti, Elena Padorno, José Antonio Jiménez, Este Capó, Fernando Pérez, Juan Manuel Sayol, Francisco Javier de los Santos, Arancha Amo, Ana Rietz, Charles Troupin, Joaquín Tintore, and Enrique Álvarez-Fanjul
Earth Syst. Sci. Data, 8, 141–149, https://doi.org/10.5194/essd-8-141-2016, https://doi.org/10.5194/essd-8-141-2016, 2016
Short summary
Short summary
An intensive drifter deployment was carried out in the Strait of Gibraltar: 35 satellite tracked drifters were released, coordinating to this aim 4 boats, covering an area of about 680 NM2 in 6 hours. This MEDESS-GIB Experiment is the most important exercise in the Mediterranean in terms of number of drifters released. The MEDESS-GIB dataset provides a complete Lagrangian view of the surface inflow of Atlantic waters through the Strait of Gibraltar and its later evolution along the Alboran Sea.
Francesco Guardamagna, Claudia Wieners, and Henk Dijkstra
Nonlin. Processes Geophys. Discuss., https://doi.org/10.5194/npg-2024-24, https://doi.org/10.5194/npg-2024-24, 2024
Preprint under review for NPG
Short summary
Short summary
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 and Cane (ZC) model. This reduced sensitivity can explain the RC's superior skills.
Bouke Biemond, Wouter Kranenburg, Ymkje Huismans, Huib E. de Swart, and Henk A. Dijkstra
EGUsphere, https://doi.org/10.5194/egusphere-2024-2322, https://doi.org/10.5194/egusphere-2024-2322, 2024
Short summary
Short summary
We study salinity in estuaries which consist of a network of channels. To this end, we develop a model which computes the flow and salinity in such systems. We use the model to quantify by which mechanisms salt is transported in estuarine networks, the response to changes in river discharge, and the impact of depth changes. Results e.g. show that when changing the depth of a channel, effects on salt intrusion in other channels in the network can be larger than the effect on the channel itself.
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
Short summary
Short summary
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.
Amber A. Boot and Henk A. Dijkstra
EGUsphere, https://doi.org/10.5194/egusphere-2024-2431, https://doi.org/10.5194/egusphere-2024-2431, 2024
Short summary
Short summary
The ocean is forced at the surface by a heat flux and freshwater flux. This noise can influence long-term ocean variability and the 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 point wise noise model performs better than the climate models and can be used as forcing in ocean-only models to study.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Sina Loriani, Yevgeny Aksenov, David Armstrong McKay, Govindasamy Bala, Andreas Born, Cristiano M. Chiessi, Henk Dijkstra, Jonathan F. Donges, Sybren Drijfhout, Matthew H. England, Alexey V. Fedorov, Laura Jackson, Kai Kornhuber, Gabriele Messori, Francesco Pausata, Stefanie Rynders, Jean-Baptiste Salée, Bablu Sinha, Steven Sherwood, Didier Swingedouw, and Thejna Tharammal
EGUsphere, https://doi.org/10.5194/egusphere-2023-2589, https://doi.org/10.5194/egusphere-2023-2589, 2023
Short summary
Short summary
In this work, we draw on paleoreords, 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 considered conceivable but currently not sufficiently supported by evidence.
Amber Adore Boot, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2023-30, https://doi.org/10.5194/esd-2023-30, 2023
Revised manuscript accepted for ESD
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
David Wichmann, Christian Kehl, Henk A. Dijkstra, and Erik van Sebille
Nonlin. Processes Geophys., 28, 43–59, https://doi.org/10.5194/npg-28-43-2021, https://doi.org/10.5194/npg-28-43-2021, 2021
Short summary
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.
Carine G. van der Boog, J. Otto Koetsier, Henk A. Dijkstra, Julie D. Pietrzak, and Caroline A. Katsman
Earth Syst. Sci. Data, 13, 43–61, https://doi.org/10.5194/essd-13-43-2021, https://doi.org/10.5194/essd-13-43-2021, 2021
Short summary
Short summary
Thermohaline staircases are stepped structures in the ocean that contain enhanced diapycnal salt and heat transport. In this study, we present a global dataset of thermohaline staircases derived from 487 493 observations of Argo profiling floats and Ice-Tethered Profilers using a novel detection algorithm.
Michiel Baatsen, Anna S. von der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, and Henk A. Dijkstra
Clim. Past, 16, 2573–2597, https://doi.org/10.5194/cp-16-2573-2020, https://doi.org/10.5194/cp-16-2573-2020, 2020
Short summary
Short summary
Warm climates of the deep past have proven to be challenging to reconstruct with the same numerical models used for future predictions. We present results of CESM simulations for the middle to late Eocene (∼ 38 Ma), in which we managed to match the available indications of temperature well. With these results we can now look into regional features and the response to external changes to ultimately better understand the climate when it is in such a warm state.
René M. van Westen and Henk A. Dijkstra
Ocean Sci., 16, 1443–1457, https://doi.org/10.5194/os-16-1443-2020, https://doi.org/10.5194/os-16-1443-2020, 2020
Short summary
Short summary
During the mid-1970s and quite recently in 2017, a large open-water area appeared in the Antarctic sea-ice pack, the so-called Maud Rise polynya. From several model studies, the reoccurrence time of this polynya seems arbitrary. In this study, we address the reoccurrence time of the polynya using a high-resolution climate model. We find a preferred multidecadal return time in polynya formation. The return time of the polynya is associated with a large-scale ocean mode in the Southern Ocean.
David Wichmann, Christian Kehl, Henk A. Dijkstra, and Erik van Sebille
Nonlin. Processes Geophys., 27, 501–518, https://doi.org/10.5194/npg-27-501-2020, https://doi.org/10.5194/npg-27-501-2020, 2020
Short summary
Short summary
The surface transport of heat, nutrients and plastic in the North Atlantic Ocean is organized into large-scale flow structures. We propose a new and simple method to detect such features in ocean drifter data sets by identifying groups of trajectories with similar dynamical behaviour using network theory. We successfully detect well-known regions such as the Subpolar and Subtropical gyres, the Western Boundary Current region and the Caribbean Sea.
René M. van Westen and Henk A. Dijkstra
Ocean Sci. Discuss., https://doi.org/10.5194/os-2020-33, https://doi.org/10.5194/os-2020-33, 2020
Revised manuscript not accepted
Short summary
Short summary
In 2016 and 2017, an open-water area emerged within the Antarctic sea-ice pack, the so-called Maud Rise polynya. The opening of the sea ice has been linked to intense winter storms. In this study, we investigate another important contributor to polynya formation by analysing subsurface static instabilities. These static instabilities initiate subsurface convection near Maud Rise. We conclude that apart from winter storms, subsurface convection plays an important role in polynya formation.
Ann Kristin Klose, René M. van Westen, and Henk A. Dijkstra
Ocean Sci., 16, 435–449, https://doi.org/10.5194/os-16-435-2020, https://doi.org/10.5194/os-16-435-2020, 2020
Short summary
Short summary
We give an explanation of the decadal timescale path variations in the Kuroshio Current in the North Pacific based on highly detailed climate
model simulations.
Carine G. van der Boog, Julie D. Pietrzak, Henk A. Dijkstra, Nils Brüggemann, René M. van Westen, Rebecca K. James, Tjeerd J. Bouma, Riccardo E. M. Riva, D. Cornelis Slobbe, Roland Klees, Marcel Zijlema, and Caroline A. Katsman
Ocean Sci., 15, 1419–1437, https://doi.org/10.5194/os-15-1419-2019, https://doi.org/10.5194/os-15-1419-2019, 2019
Short summary
Short summary
We use a model of the Caribbean Sea to study how coastal upwelling along Venezuela impacts the evolution of energetic anticyclonic eddies. We show that the anticyclones grow by the advection of the cold upwelling filaments. These filaments increase the density gradient and vertical shear of the anticyclones. Furthermore, we show that stronger upwelling results in stronger eddies, while model simulations with weaker upwelling contain weaker eddies.
Henk A. Dijkstra
Nonlin. Processes Geophys., 26, 359–369, https://doi.org/10.5194/npg-26-359-2019, https://doi.org/10.5194/npg-26-359-2019, 2019
Short summary
Short summary
I provide a personal view on the role of bifurcation analysis of climate models in the development of a theory of variability in the climate system. By outlining the state of the art of the methodology and by discussing what has been done and what has been learned from a hierarchy of models, I will argue that there are low-order phenomena of climate variability, such as El Niño and the Atlantic Multidecadal Oscillation.
Koen G. Helwegen, Claudia E. Wieners, Jason E. Frank, and Henk A. Dijkstra
Earth Syst. Dynam., 10, 453–472, https://doi.org/10.5194/esd-10-453-2019, https://doi.org/10.5194/esd-10-453-2019, 2019
Short summary
Short summary
We use the climate-economy model DICE to perform a cost–benefit analysis of sulfate geoengineering, i.e. producing a thin artificial sulfate haze in the higher atmosphere to reflect some sunlight and cool the Earth.
We find that geoengineering can increase future welfare by reducing global warming, and should be taken seriously as a policy option, but it can only complement, not replace, carbon emission reduction. The best policy is to combine CO2 emission reduction with modest geoengineering.
Martijn Westhoff, Axel Kleidon, Stan Schymanski, Benjamin Dewals, Femke Nijsse, Maik Renner, Henk Dijkstra, Hisashi Ozawa, Hubert Savenije, Han Dolman, Antoon Meesters, and Erwin Zehe
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2019-6, https://doi.org/10.5194/esd-2019-6, 2019
Publication in ESD not foreseen
Short summary
Short summary
Even models relying on physical laws have parameters that need to be measured or estimated. Thermodynamic optimality principles potentially offer a way to reduce the number of estimated parameters by stating that a system evolves to an optimum state. These principles have been applied successfully within the Earth system, but it is often unclear what to optimize and how. In this review paper we identify commonalities between different successful applications as well as some doubtful applications.
Mark M. Dekker, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 9, 1243–1260, https://doi.org/10.5194/esd-9-1243-2018, https://doi.org/10.5194/esd-9-1243-2018, 2018
Short summary
Short summary
We introduce a framework of cascading tipping, i.e. a sequence of abrupt transitions occurring because a transition in one system affects the background conditions of another system. Using bifurcation theory, various types of these events are considered and early warning indicators are suggested. An illustration of such an event is found in a conceptual model, coupling the North Atlantic Ocean with the equatorial Pacific. This demonstrates the possibility of events such as this in nature.
Matthias Aengenheyster, Qing Yi Feng, Frederick van der Ploeg, and Henk A. Dijkstra
Earth Syst. Dynam., 9, 1085–1095, https://doi.org/10.5194/esd-9-1085-2018, https://doi.org/10.5194/esd-9-1085-2018, 2018
Short summary
Short summary
We determine the point of no return (PNR) for climate change, which is the latest year to take action to reduce greenhouse gases to stay, with a certain probability, within thresholds set by the Paris Agreement. For a 67 % probability and a 2 K threshold, the PNR is the year 2035 when the share of renewable energy rises by 2 % per year. We show the impact on the PNR of the speed by which emissions are cut, the risk tolerance, climate uncertainties and the potential for negative emissions.
Femke J. M. M. Nijsse and Henk A. Dijkstra
Earth Syst. Dynam., 9, 999–1012, https://doi.org/10.5194/esd-9-999-2018, https://doi.org/10.5194/esd-9-999-2018, 2018
Short summary
Short summary
State-of-the-art climate models sometimes differ in their prediction of key aspects of climate change. The technique of
emergent constraintsuses observations of current climate to improve those predictions, using relationships between different climate models. Our paper first classifies the different uses of the technique, and continues with proposing a mathematical justification for their use. We also highlight when the application of emergent constraints might give biased predictions.
Peter D. Nooteboom, Qing Yi Feng, Cristóbal López, Emilio Hernández-García, and Henk A. Dijkstra
Earth Syst. Dynam., 9, 969–983, https://doi.org/10.5194/esd-9-969-2018, https://doi.org/10.5194/esd-9-969-2018, 2018
Short summary
Short summary
The prediction of the El Niño phenomenon, an increased sea surface temperature in the eastern Pacific, fascinates people for a long time. El Niño is associated with natural disasters, such as droughts and floods. Current methods can make a reliable prediction of this phenomenon up to 6 months ahead. However, this article presents a method which combines network theory and machine learning which predicts El Niño up to 1 year ahead.
Michiel Baatsen, Anna S. von der Heydt, Matthew Huber, Michael A. Kliphuis, Peter K. Bijl, Appy Sluijs, and Henk A. Dijkstra
Clim. Past Discuss., https://doi.org/10.5194/cp-2018-43, https://doi.org/10.5194/cp-2018-43, 2018
Revised manuscript not accepted
Short summary
Short summary
The Eocene marks a period where the climate was in a hothouse state, without any continental-scale ice sheets. Such climates have proven difficult to reproduce in models, especially their low temperature difference between equator and poles. Here, we present high resolution CESM simulations using a new geographic reconstruction of the middle-to-late Eocene. The results provide new insights into a period for which knowledge is limited, leading up to a transition into the present icehouse state.
Inti Pelupessy, Ben van Werkhoven, Arjen van Elteren, Jan Viebahn, Adam Candy, Simon Portegies Zwart, and Henk Dijkstra
Geosci. Model Dev., 10, 3167–3187, https://doi.org/10.5194/gmd-10-3167-2017, https://doi.org/10.5194/gmd-10-3167-2017, 2017
Short summary
Short summary
Researchers from the Netherlands present OMUSE, a software package
developed from core technology originating in the astrophysical
community. Using OMUSE, oceanographic and climate researchers can
develop numerical models of the ocean and the interactions between
different parts of the ocean and the atmosphere. This provides a novel
way to investigate, for example, the local effects of climate change on
the ocean. OMUSE is freely available as open-source software.
Brenda C. van Zalinge, Qing Yi Feng, Matthias Aengenheyster, and Henk A. Dijkstra
Earth Syst. Dynam., 8, 707–717, https://doi.org/10.5194/esd-8-707-2017, https://doi.org/10.5194/esd-8-707-2017, 2017
Short summary
Short summary
The increase in atmospheric greenhouse gases (GHGs) is one of the main causes for the increase in global mean surface temperature. There is no good quantitative measure to determine when it is
too lateto start reducing GHGs in order to avoid dangerous anthropogenic interference. We develop a method for determining a so-called point of no return (PNR) for several GHG emission scenarios. The innovative element in this approach is the applicability to high-dimensional climate models.
Daniel J. Lunt, Matthew Huber, Eleni Anagnostou, Michiel L. J. Baatsen, Rodrigo Caballero, Rob DeConto, Henk A. Dijkstra, Yannick Donnadieu, David Evans, Ran Feng, Gavin L. Foster, Ed Gasson, Anna S. von der Heydt, Chris J. Hollis, Gordon N. Inglis, Stephen M. Jones, Jeff Kiehl, Sandy Kirtland Turner, Robert L. Korty, Reinhardt Kozdon, Srinath Krishnan, Jean-Baptiste Ladant, Petra Langebroek, Caroline H. Lear, Allegra N. LeGrande, Kate Littler, Paul Markwick, Bette Otto-Bliesner, Paul Pearson, Christopher J. Poulsen, Ulrich Salzmann, Christine Shields, Kathryn Snell, Michael Stärz, James Super, Clay Tabor, Jessica E. Tierney, Gregory J. L. Tourte, Aradhna Tripati, Garland R. Upchurch, Bridget S. Wade, Scott L. Wing, Arne M. E. Winguth, Nicky M. Wright, James C. Zachos, and Richard E. Zeebe
Geosci. Model Dev., 10, 889–901, https://doi.org/10.5194/gmd-10-889-2017, https://doi.org/10.5194/gmd-10-889-2017, 2017
Short summary
Short summary
In this paper we describe the experimental design for a set of simulations which will be carried out by a range of climate models, all investigating the climate of the Eocene, about 50 million years ago. The intercomparison of model results is called 'DeepMIP', and we anticipate that we will contribute to the next IPCC report through an analysis of these simulations and the geological data to which we will compare them.
S.-E. Brunnabend, H. A. Dijkstra, M. A. Kliphuis, H. E. Bal, F. Seinstra, B. van Werkhoven, J. Maassen, and M. van Meersbergen
Ocean Sci., 13, 47–60, https://doi.org/10.5194/os-13-47-2017, https://doi.org/10.5194/os-13-47-2017, 2017
Short summary
Short summary
An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a strongly eddying version of the Parallel Ocean Program. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways.
Michiel Baatsen, Douwe J. J. van Hinsbergen, Anna S. von der Heydt, Henk A. Dijkstra, Appy Sluijs, Hemmo A. Abels, and Peter K. Bijl
Clim. Past, 12, 1635–1644, https://doi.org/10.5194/cp-12-1635-2016, https://doi.org/10.5194/cp-12-1635-2016, 2016
Short summary
Short summary
One of the major difficulties in modelling palaeoclimate is constricting the boundary conditions, causing significant discrepancies between different studies. Here, a new method is presented to automate much of the process of generating the necessary geographical reconstructions. The latter can be made using various rotational frameworks and topography/bathymetry input, allowing for easy inter-comparisons and the incorporation of the latest insights from geoscientific research.
Zun Yin, Stefan C. Dekker, Bart J. J. M. van den Hurk, and Henk A. Dijkstra
Biogeosciences, 13, 3343–3357, https://doi.org/10.5194/bg-13-3343-2016, https://doi.org/10.5194/bg-13-3343-2016, 2016
Short summary
Short summary
Bimodality is found in aboveground biomass and mean annual shortwave radiation in West Africa, which is a strong evidence of alternative stable states. The condition with low biomass and low radiation is demonstrated under which ecosystem state can shift between savanna and forest states. Moreover, climatic indicators have different prediction confidences to different land cover types. A new method is proposed to predict potential land cover change with a combination of climatic indicators.
Marcos García Sotillo, Emilio Garcia-Ladona, Alejandro Orfila, Pablo Rodríguez-Rubio, José Cristobal Maraver, Daniel Conti, Elena Padorno, José Antonio Jiménez, Este Capó, Fernando Pérez, Juan Manuel Sayol, Francisco Javier de los Santos, Arancha Amo, Ana Rietz, Charles Troupin, Joaquín Tintore, and Enrique Álvarez-Fanjul
Earth Syst. Sci. Data, 8, 141–149, https://doi.org/10.5194/essd-8-141-2016, https://doi.org/10.5194/essd-8-141-2016, 2016
Short summary
Short summary
An intensive drifter deployment was carried out in the Strait of Gibraltar: 35 satellite tracked drifters were released, coordinating to this aim 4 boats, covering an area of about 680 NM2 in 6 hours. This MEDESS-GIB Experiment is the most important exercise in the Mediterranean in terms of number of drifters released. The MEDESS-GIB dataset provides a complete Lagrangian view of the surface inflow of Atlantic waters through the Strait of Gibraltar and its later evolution along the Alboran Sea.
Qing Yi Feng, Ruggero Vasile, Marc Segond, Avi Gozolchiani, Yang Wang, Markus Abel, Shilomo Havlin, Armin Bunde, and Henk A. Dijkstra
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2015-273, https://doi.org/10.5194/gmd-2015-273, 2016
Revised manuscript not accepted
Short summary
Short summary
We present the toolbox ClimateLearn to tackle problems in climate prediction using machine learning techniques and climate network analysis. Because spatial temporal information on climate variability can be efficiently represented by complex network measures, such data are considered here as input to the machine-learning algorithms. As an example, the toolbox is applied to the prediction of the occurrence and the development of El Niño in the equatorial Pacific.
H. Ihshaish, A. Tantet, J. C. M. Dijkzeul, and H. A. Dijkstra
Geosci. Model Dev., 8, 3321–3331, https://doi.org/10.5194/gmd-8-3321-2015, https://doi.org/10.5194/gmd-8-3321-2015, 2015
Short summary
Short summary
Par@Graph, a software toolbox to reconstruct and analyze large-scale complex climate networks. It exposes parallelism on distributed-memory computing platforms to enable the construction of massive networks from large number of time series based on the calculation of common statistical similarity measures between them. Providing additionally parallel graph algorithms to enable fast calculation of important and common properties of the generated networks on SMP machines.
L. Hahn-Woernle, H. A. Dijkstra, and H. J. Van der Woerd
Ocean Sci., 10, 993–1011, https://doi.org/10.5194/os-10-993-2014, https://doi.org/10.5194/os-10-993-2014, 2014
Short summary
Short summary
Measured vertical mixing profiles are applied to a 1-D phytoplankton model. Results show that shifts in vertical mixing are able to induce a transition from an upper chlorophyll maximum to a deep one and vice versa. Furthermore, a clear correlation between the surface phytoplankton concentration and mixing-induced nutrient flux is found for nutrient-limited cases. This result suggests that characteristics of the vertical mixing could be determined from the surface phytoplankton concentration.
S.-E. Brunnabend, H. A. Dijkstra, M. A. Kliphuis, B. van Werkhoven, H. E. Bal, F. Seinstra, J. Maassen, and M. van Meersbergen
Ocean Sci., 10, 881–891, https://doi.org/10.5194/os-10-881-2014, https://doi.org/10.5194/os-10-881-2014, 2014
Short summary
Short summary
Regional sea surface height (SSH) changes due to an abrupt weakening of the Atlantic meridional overturning circulation (AMOC) are simulated with a high- and low-resolution model. A rapid decrease of the AMOC in the high-resolution version induces shorter return times of several specific regional and coastal extremes in North Atlantic SSH than in the low-resolution version. This effect is caused by a change in main eddy pathways associated with a change in separation latitude of the Gulf Stream.
Z. Yin, S. C. Dekker, B. J. J. M. van den Hurk, and H. A. Dijkstra
Earth Syst. Dynam., 5, 257–270, https://doi.org/10.5194/esd-5-257-2014, https://doi.org/10.5194/esd-5-257-2014, 2014
D. Le Bars, J. V. Durgadoo, H. A. Dijkstra, A. Biastoch, and W. P. M. De Ruijter
Ocean Sci., 10, 601–609, https://doi.org/10.5194/os-10-601-2014, https://doi.org/10.5194/os-10-601-2014, 2014
Z. Yin, S. C. Dekker, B. J. J. M. van den Hurk, and H. A. Dijkstra
Geosci. Model Dev., 7, 821–845, https://doi.org/10.5194/gmd-7-821-2014, https://doi.org/10.5194/gmd-7-821-2014, 2014
G. Sgubin, S. Pierini, and H. A. Dijkstra
Ocean Sci., 10, 201–213, https://doi.org/10.5194/os-10-201-2014, https://doi.org/10.5194/os-10-201-2014, 2014
A. Tantet and H. A. Dijkstra
Earth Syst. Dynam., 5, 1–14, https://doi.org/10.5194/esd-5-1-2014, https://doi.org/10.5194/esd-5-1-2014, 2014
A. A. Cimatoribus, S. Drijfhout, and H. A. Dijkstra
Ocean Sci. Discuss., https://doi.org/10.5194/osd-10-2461-2013, https://doi.org/10.5194/osd-10-2461-2013, 2013
Preprint withdrawn
A. S. von der Heydt, A. Nnafie, and H. A. Dijkstra
Clim. Past, 7, 903–915, https://doi.org/10.5194/cp-7-903-2011, https://doi.org/10.5194/cp-7-903-2011, 2011
M. Tigchelaar, A. S. von der Heydt, and H. A. Dijkstra
Clim. Past, 7, 235–247, https://doi.org/10.5194/cp-7-235-2011, https://doi.org/10.5194/cp-7-235-2011, 2011
J. O. Sewall, R. S. W. van de Wal, K. van der Zwan, C. van Oosterhout, H. A. Dijkstra, and C. R. Scotese
Clim. Past, 3, 647–657, https://doi.org/10.5194/cp-3-647-2007, https://doi.org/10.5194/cp-3-647-2007, 2007
Related subject area
Approach: Numerical Models | Depth range: All Depths | Geographical range: Deep Seas: North Atlantic | Phenomena: Current Field
Barotropic vorticity balance of the North Atlantic subpolar gyre in an eddy-resolving model
The role of subpolar deep water formation and Nordic Seas overflows in simulated multidecadal variability of the Atlantic meridional overturning circulation
The circulation of Icelandic waters – a modelling study
An operational model for the West Iberian coast: products and services
Particle aggregation at the edges of anticyclonic eddies and implications for distribution of biomass
A multi-decadal meridional displacement of the Subpolar Front in the Newfoundland Basin
Observed and simulated estimates of the meridional overturning circulation at 26.5° N in the Atlantic
Mathieu Le Corre, Jonathan Gula, and Anne-Marie Tréguier
Ocean Sci., 16, 451–468, https://doi.org/10.5194/os-16-451-2020, https://doi.org/10.5194/os-16-451-2020, 2020
Short summary
Short summary
The ocean circulation is crucial for the climate, and the North Atlantic subpolar gyre is a key component of the meridional heat transport. In this study we use a high-resolution simulation with bottom-following coordinates to investigate the gyre dynamics. We show that nonlinear processes, underestimated in most climate models, control the circulation in the gyre interior. This result contrasts with the classical theory putting forward wind effects on the large-scale circulation.
K. Lohmann, J. H. Jungclaus, D. Matei, J. Mignot, M. Menary, H. R. Langehaug, J. Ba, Y. Gao, O. H. Otterå, W. Park, and S. Lorenz
Ocean Sci., 10, 227–241, https://doi.org/10.5194/os-10-227-2014, https://doi.org/10.5194/os-10-227-2014, 2014
K. Logemann, J. Ólafsson, Á. Snorrason, H. Valdimarsson, and G. Marteinsdóttir
Ocean Sci., 9, 931–955, https://doi.org/10.5194/os-9-931-2013, https://doi.org/10.5194/os-9-931-2013, 2013
M. Mateus, G. Riflet, P. Chambel, L. Fernandes, R. Fernandes, M. Juliano, F. Campuzano, H. de Pablo, and R. Neves
Ocean Sci., 8, 713–732, https://doi.org/10.5194/os-8-713-2012, https://doi.org/10.5194/os-8-713-2012, 2012
A. Samuelsen, S. S. Hjøllo, J. A. Johannessen, and R. Patel
Ocean Sci., 8, 389–400, https://doi.org/10.5194/os-8-389-2012, https://doi.org/10.5194/os-8-389-2012, 2012
I. Núñez-Riboni, M. Bersch, H. Haak, J. H. Jungclaus, and K. Lohmann
Ocean Sci., 8, 91–102, https://doi.org/10.5194/os-8-91-2012, https://doi.org/10.5194/os-8-91-2012, 2012
J. Baehr, S. Cunnningham, H. Haak, P. Heimbach, T. Kanzow, and J. Marotzke
Ocean Sci., 5, 575–589, https://doi.org/10.5194/os-5-575-2009, https://doi.org/10.5194/os-5-575-2009, 2009
Cited articles
Adcroft, A., Hill, C., and Marshall, J.: Representation of Topography by Shaved
Cells in a Height Coordinate Ocean Model, Mon. Weather Rev., 125,
2293–2315, https://doi.org/10.1175/1520-0493(1997)125<2293:ROTBSC>2.0.CO;2, 1997. a
Azetsu-Scott, K., Petrie, B., Yeats, P., and Lee, C.: Composition and fluxes
of freshwater through Davis Strait using multiple chemical tracers, J. Geophys. Res.-Oceans, 117, C12011, https://doi.org/10.1029/2012JC008172, 2012. a
Bower, A. S. and Hunt, H. D.: Lagrangian Observations of the Deep Western
Boundary Current in the North Atlantic Ocean., J. Phys. Oceanogr., 30, 764–783,
https://doi.org/10.1175/1520-0485(2000)030<0764:LOOTDW>2.0.CO;2, 2000. a
Bower, A. S., Lozier, M. S., Gary, S. F., and Böning, C. W.: Interior
pathways of the North Atlantic meridional overturning circulation, Nature,
459, 243–247, https://doi.org/10.1038/nature07979, 2009. a
Brambilla, E. and Talley, L. D.: Surface drifter exchange between the North
Atlantic subtropical and subpolar gyres, J. Geophys. Res.-Oceans, 111, C07026, https://doi.org/10.1029/2005JC003146, 2006. a
Broecker, W. S.: The Biggest Chill: When Ocean Currents Shifted, Europe
Suddenly Got Cold; Could it Happen Again?, Nat. Hist., 96, 74–82, 1987. a
Broecker, W. S.: The Great Ocean Conveyor, Oceanography, 4, 79–89,
https://doi.org/10.5670/oceanog.1991.07, 1991. a
Brüggemann, N., Katsman, C. A., and Dijkstra, H. A.: On the vorticity
dynamics of the downwelling branch of the AMOC, CLIVAR Exchanges Special
Issue: CLIVAR Open Science Conference Award Winners, 71, 10–12, 2017. a
Brunnabend, S.-E. and Dijkstra, H. A.: Asymmetric response of the Atlantic
Meridional Ocean Circulation to freshwater anomalies in a strongly-eddying
global ocean model, Tellus A, 69,
1299283, https://doi.org/10.1080/16000870.2017.1299283, 2017. a, b, c
Buckley, M. W. and Marshall, J.: Observations, inferences, and mechanisms of
the Atlantic Meridional Overturning Circulation: A review, Rev. Geophys., 54, 5–63, https://doi.org/10.1002/2015RG000493, 2016. a
Cenedese, C.: Downwelling in Basins Subject to Buoyancy Loss, J. Phys. Oceanogr., 42, 1817–1833, https://doi.org/10.1175/JPO-D-11-0114.1, 2012. a
Cunningham, S. A., Kanzow, T., Rayner, D., Baringer, M. O., Johns, W. E.,
Marotzke, J., Longworth, H. R., Grant, E. M., Hirschi, J. J.-M., Beal, L. M.,
Meinen, C. S., and Bryden, H. L.: Temporal Variability of the Atlantic
Meridional Overturning Circulation at 26.5∘ N, Science, 317,
935–938, https://doi.org/10.1126/science.1141304, 2007. a
de Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A., and Iudicone,
D.: Mixed layer depth over the global ocean: An examination of profile data
and a profile-based climatology, J. Geophys. Res.-Oceans,
109, C12003, https://doi.org/10.1029/2004JC002378, 2004. a
Frajka-Williams, E., Eriksen, C. C., Rhines, P. B., and Harcourt, R. R.:
Determining Vertical Water Velocities from Seaglider, J. Atmos. Ocean. Tech., 28, 1641–1656,
https://doi.org/10.1175/2011JTECHO830.1, 2011. a
Georgiou, S., van der Boog, C. G., Brüggemann, N., Ypma, S. L., Pietrzak,
J. D., and Katsman, C. A.: On the interplay between downwelling, deep
convection and mesoscale eddies in the Labrador Sea, Ocean Model., 135, 56–70, https://doi.org/10.1016/j.ocemod.2019.02.004, 2019. a, b, c, d, e, f, g, h, i, j, k, l
Holliday, N. P., Bacon, S., Cunningham, S. A., Gary, S. F., Karstensen, J.,
King, B. A., Li, F., and Mcdonagh, E. L.: Subpolar North Atlantic
Overturning and Gyre-Scale Circulation in the Summers of 2014 and 2016,
J. Geophys. Res.-Oceans, 123, 4538–4559, https://doi.org/10.1029/2018JC013841, 2018. a, b
Holte, J. and Straneo, F.: Seasonal Overturning of the Labrador Sea as
Observed by Argo Floats, J. Phys. Oceanogr., 47, 2531–2543,
https://doi.org/10.1175/JPO-D-17-0051.1, 2017. a, b
Holte, J., Talley, L. D., Gilson, J., and Roemmich, D.: An Argo mixed layer
climatology and database, Geophys. Res. Lett., 44, 5618–5626,
https://doi.org/10.1002/2017GL073426, 2017. a
Håvik, L., Våge, K., Pickart, R. S., Harden, B., Appen, W.,
Jónsson, S., and Østerhus, S.: Structure and Variability of the
Shelfbreak East Greenland Current North of Denmark Strait, J. Phys. Oceanogr., 47, 2631–2646, https://doi.org/10.1175/JPO-D-17-0062.1, 2017. a
Jochumsen, K., Quadfasel, D., Valdimarsson, H., and Jónsson, S.: Variability
of the Denmark Strait overflow: Moored time series from 1996–2011, J. Geophys. Res.-Oceans, 117, C12003, https://doi.org/10.1029/2012JC008244, 2012. a
Jochumsen, K., Moritz, M., Nunes, N., Quadfasel, D., Larsen, K. M. H., Hansen,
B., Valdimarsson, H., and Jonsson, S.: Revised transport estimates of the
Denmark Strait overflow, J. Geophys. Res.-Oceans, 122,
3434–3450, https://doi.org/10.1002/2017JC012803, 2017. a, b
Kanzow, T., Cunningham, S. A., Johns, W. E., Hirschi, J. J.-M., Marotzke, J.,
Baringer, M. O., Meinen, C. S., Chidichimo, M. P., Atkinson, C., Beal, L. M.,
Bryden, H. L., and Collins, J.: Seasonal Variability of the Atlantic
Meridional Overturning Circulation at 26.5∘ N, J. Climate,
23, 5678–5698, https://doi.org/10.1175/2010JCLI3389.1, 2010. a
Köhl, A., Käse, R. H., Stammer, D., and Serra, N.: Causes of Changes
in the Denmark Strait Overflow, J. Phys. Oceanogr., 37,
1678–1696, https://doi.org/10.1175/JPO3080.1, 2007. a
Kornei, K.: Ocean array alters view of Atlantic conveyor, Science, 359,
857–857, https://doi.org/10.1126/science.359.6378.857, 2018. a
Large, W. G. and Yeager, S.: Diurnal to decadal global forcing for ocean and
sea-ice models: The data sets and flux climatologies, Tech. rep., National
Center for Atmospheric Research, Boulder, CO, USA, 2004. a
Lozier, M. S.: Deconstructing the Conveyor Belt, Science, 328, 1507–1511,
https://doi.org/10.1126/science.1189250, 2010. a
Lozier, M. S.: Overturning in the North Atlantic, Annu. Rev. Mar. Sci., 4, 291–315, https://doi.org/10.1146/annurev-marine-120710-100740, 2012. a
Lozier, M. S., Bacon, S., Bower, A. S., Cunningham, S. A., Femke de Jong, M.,
de Steur, L., de Young, B., Fischer, J., Gary, S. F., Greenan, B. J. W.,
Heimbach, P., Holliday, N. P., Houpert, L., Inall, M. E., Johns, W. E.,
Johnson, H. L., Karstensen, J., Li, F., Lin, X., Mackay, N., Marshall, D. P.,
Mercier, H., Myers, P. G., Pickart, R. S., Pillar, H. R., Straneo, F.,
Thierry, V., Weller, R. A., Williams, R. G., Wilson, C., Yang, J., Zhao, J.,
and Zika, J. D.: Overturning in the Subpolar North Atlantic Program: A New
International Ocean Observing System, B. Am. Meteorol. Soc., 98, 737–752, https://doi.org/10.1175/BAMS-D-16-0057.1, 2017. a
Lozier, M. S., Li, F., Bacon, S., Bahr, F., Bower, A. S., Cunningham, S. A.,
de Jong, M. F., de Steur, L., deYoung, B., Fischer, J., Gary, S. F., Greenan,
B. J. W., Holliday, N. P., Houk, A., Houpert, L., Inall, M. E., Johns, W. E.,
Johnson, H. L., Johnson, C., Karstensen, J., Koman, G., Le Bras, I. A., Lin,
X., Mackay, N., Marshall, D. P., Mercier, H., Oltmanns, M., Pickart, R. S.,
Ramsey, A. L., Rayner, D., Straneo, F., Thierry, V., Torres, D. J., Williams,
R. G., Wilson, C., Yang, J., Yashayaev, I., and Zhao, J.: A sea change in our
view of overturning in the subpolar North Atlantic, Science, 363, 516–521,
https://doi.org/10.1126/science.aau6592, 2019. a, b, c
Maltrud, M. E., Bryan, F., Hecht, M., Hunke, E., Ivanova, D., McClean, J., and
Peacock, S.: Global ocean modelling in the eddying regime using POP, CLIVAR
Exchanges, 44, 5–8, 2008. a
Maltrud, M. E., Bryan, F., and Peacock, S.: Boundary impulse response
functions in a century-long eddying global ocean simulation, Environ. Fluid Mech., 10, 275–295, https://doi.org/10.1007/s10652-009-9154-3, 2010. a, b
Marshall, J. and Schott, F.: Open-ocean convection: Observations, theory, and
models, Rev. Geophys., 37, 1–64, https://doi.org/10.1029/98RG02739, 1999. a
Pedlosky, J. and Spall, M. A.: Boundary Intensification of Vertical Velocity
in a β-Plane Basin, J. Phys. Oceanogr., 35, 2487–2500,
https://doi.org/10.1175/JPO2832.1, 2005. a
Pickart, R. S. and Spall, M. A.: Impact of Labrador Sea Convection on the
North Atlantic Meridional Overturning Circulation, J. Phys. Oceanogr., 37, 2207–2227, https://doi.org/10.1175/JPO3178.1, 2007. a
Rudels, B., Björk, G., Nilsson, J., Winsor, P., Lake, I., and Nohr, N.: The
interaction between waters from the Arctic Ocean and the Nordic Seas north of
Fram Strait and along the East Greenland Current: results from the Arctic
Ocean-02 Oden expedition, J. Marine Syst., 55, 1–30,
https://doi.org/10.1016/j.jmarsys.2004.06.008, 2005. a
Rypina, I. I., Pratt, L. J., and Lozier, M. S.: Near-Surface Transport
Pathways in the North Atlantic Ocean: Looking for Throughput from the
Subtropical to the Subpolar Gyre, J. Phys. Oceanogr., 41,
911–925, https://doi.org/10.1175/2011JPO4498.1, 2011. a
Send, U. and Marshall, J.: Integral Effects of Deep Convection, J. Phys. Oceanogr., 25, 855–872,
https://doi.org/10.1175/1520-0485(1995)025<0855:IEODC>2.0.CO;2, 1995. a
Shapiro, G. I. and Hill, A.: Dynamics of Dense Water Cascades at the Shelf
Edge, J. Phys. Oceanogr., 27, 2381–2394,
https://doi.org/10.1175/1520-0485(1997)027<2381:DODWCA>2.0.CO;2, 1997. a
Sinha, B., Smeed, D. A., McCarthy, G., Moat, B. I., Josey, S., Hirschi,
J. J.-M., Frajka-Williams, E., Blaker, A. T., Rayner, D., and Madec, G.: The
accuracy of estimates of the overturning circulation from basin-wide mooring
arrays, Prog. Oceanogr., 160, 101–123,
https://doi.org/10.1016/j.pocean.2017.12.001, 2018. a
Smeed, D. A., McCarthy, G. D., Cunningham, S. A., Frajka-Williams, E., Rayner, D., Johns, W. E., Meinen, C. S., Baringer, M. O., Moat, B. I., Duchez, A., and Bryden, H. L.: Observed decline of the Atlantic meridional overturning circulation 2004–2012, Ocean Sci., 10, 29–38, https://doi.org/10.5194/os-10-29-2014, 2014. a, b
Smeed, D. A., Josey, S. A., Beaulieu, C., Johns, W. E., Moat, B. I.,
Frajka-Williams, E., Rayner, D., Meinen, C. S., Baringer, M. O., Bryden,
H. L., and McCarthy, G. D.: The North Atlantic Ocean Is in a State of
Reduced Overturning, Geophys. Res. Lett., 45, 1527–1533,
https://doi.org/10.1002/2017GL076350, 2018. a, b
Smith, R., Jones, P., Briegleb, B., Bryan, F., Danabasoglu, G., Dennis, J.,
Dukowic, z, J., Eden, C., Fox-Kemper, B., Gent, P., Hecht, M., Jayne, S.,
Jochum, M., Large, W., Lindsay, K., Maltrud, M., Norton, N., Peacock, S.,
Vertenstein, M., and Yeager, S.: The Parallel Ocean Program (POP) Reference
Manual: Ocean Component of the Community Climate System Model (CCSM) and
Community Earth System Model (CESM), Tech. rep., Los Alamos National
Laboratory, National Center for Atmospheric Research, IFM-GEOMAR, Univ. Kiel,
University of Colorado-Boulder, Woods Hole Oceanographic Institution, 2010. a
Spall, M. A.: Boundary Currents and Watermass Transformation in Marginal
Seas, J. Phys. Oceanogr., 34, 1197–1213,
https://doi.org/10.1175/1520-0485(2004)034<1197:BCAWTI>2.0.CO;2, 2004. a, b
Spall, M. A.: Buoyancy-Forced Downwelling in Boundary Currents, J. Phys. Oceanogr., 38, 2704–2721, https://doi.org/10.1175/2008JPO3993.1, 2008. a
Spall, M. A.: Dynamics of Downwelling in an Eddy-Resolving Convective Basin,
J. Phys. Oceanogr., 40, 2341–2347,
https://doi.org/10.1175/2010JPO4465.1, 2010. a, b, c, d
Spall, M. A.: On the Role of Eddies and Surface Forcing in the Heat Transport
and Overturning Circulation in Marginal Seas, J. Climate, 24,
4844–4858, https://doi.org/10.1175/2011JCLI4130.1, 2011. a
Stommel, H. and Arons, A.: On the abyssal circulation of the world ocean—I.
Stationary planetary flow patterns on a sphere, Deep-Sea Res., 6,
140–154, https://doi.org/10.1016/0146-6313(59)90065-6, 1959. a
Straneo, F.: On the Connection between Dense Water Formation, Overturning, and
Poleward Heat Transport in a Convective Basin, J. Phys. Oceanogr., 36, 1822–1840, https://doi.org/10.1175/JPO2932.1, 2006. a, b, c, d
Våge, K., Pickart, R. S., Thierry, V., Reverdin, G., Lee, C. M., Petrie,
B., Agnew, T. A., Wong, A., and Ribergaard, M. H.: Surprising return of deep
convection to the subpolar North Atlantic Ocean in winter 2007–2008, Nat. Geosci., 2, 67–72, https://doi.org/10.1038/ngeo382, 2009. a
Waldman, R., Brüggemann, N., Bosse, A., Spall, M., Somot, S., and Sevault,
F.: Overturning the Mediterranean Thermohaline Circulation, Geophys. Res. Lett., 45, 8407–8415, https://doi.org/10.1029/2018GL078502, 2018. a
Weijer, W., Maltrud, M. E., Hecht, M. W., Dijkstra, H. A., and Kliphuis, M. A.:
Response of the Atlantic Ocean circulation to Greenland Ice Sheet melting in
a strongly-eddying ocean model, Geophys. Res. Lett., 39, L09606, https://doi.org/10.1029/2012GL051611, 2012. a, b
Yankovsky, E. and Legg, S.: Symmetric and Baroclinic Instability in Dense
Shelf Overflows, J. Phys. Oceanogr., 49, 39–61,
https://doi.org/10.1175/JPO-D-18-0072.1, 2019. a
Short summary
This work uses high-resolution ocean model data to quantify the sinking of waters in the subpolar North Atlantic. The largest amount of sinking is found at the depth of maximum AMOC at 45° N below the mixed layer depth, and 90 % of the sinking occurs near the boundaries in the first 250 km off the shelf. The characteristics of the sinking (total amount, seasonal variability, and vertical structure) vary largely according to the region considered, revealing a complex picture for the sinking.
This work uses high-resolution ocean model data to quantify the sinking of waters in the...
