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1. Sources of low-frequency $\delta^{18}$O variability in coastal ice cores from Dronning Maud Land

Author

Vannitsem, Stéphane, Docquier, David, Wauthy, Sarah, Corkill, Matthew, and Tison, Jean-Louis

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

The low-frequency variability of the $\delta^{18}$O recorded in ice cores (FK17 and TIR18) recently drilled at two different locations in Dronning Maud Land (Antarctica), is investigated using multi-taper spectral method and singular spectrum analysis. Multiple dominant peaks emerge in these records with periods between 3 and 20 years. The two sites show distinct spectral signatures, despite their relative proximity in space (about 100 km apart), suggesting that different processes are involved in generating the variability at these two sites. In order to clarify which processes are acting on $\delta^{18}$O at these two locations, the impact of several climate indices as well as sea ice area is investigated using a causal method, known as the Liang-Kleeman rate of information transfer. The analysis of the origin of this low-frequency variability from external sources reveals that El Ni\~no-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Southern Annular Mode (SAM), the Dipole Mode Index (DMI) and the sea ice area display important causal influences on $\delta^{18}$O at FK17. For TIR18, the main influences are from ENSO, PDO, DMI, the sea ice area, and the Atlantic Multidecadal Oscillation (AMO), revealing the complexity of the interactions in Dronning Maud Land. The two locations share several drivers, but also show local specificities potentially linked to ocean proximity and differences in air mass trajectories. The implication of these findings on the low-frequency variability in the two ice cores is discussed., Comment: 22 pages, 9 figures. Submitted to Climate Dynamics

Published
2024

2. Causal dependencies and Shannon entropy budget -- Analysis of a reduced order atmospheric model

Author

Vannitsem, Stéphane, Pires, Carlos A., and Docquier, David

Subjects
Physics - Atmospheric and Oceanic Physics, Nonlinear Sciences - Chaotic Dynamics
Abstract

The information entropy budget and the rate of information transfer between variables is studied in the context of a nonlinear reduced-order atmospheric model. The key ingredients of the dynamics are present in this model, namely the baroclinic and barotropic instabilities, the instability related to the presence of an orography, the dissipation related to the surface friction, and the large-scale meridional imbalance of energy. For the parameter chosen, the solutions of this system display a chaotic dynamics reminiscent of the large-scale atmospheric dynamics in the extra-tropics. The detailed information entropy budget analysis of this system reveals that the linear rotation terms plays a minor role in the generation of uncertainties as compared to the orography and the surface friction. Additionally, the dominant contribution comes from the nonlinear advection terms, and their decomposition in synergetic (co-variability) and single (impact of each single variable on the target one) components reveals that for some variables the co-variability dominates the information transfer. The estimation of the rate of information transfer based on time series is also discussed, and an extension of the Liang's approach to nonlinear observables, is proposed., Comment: 26 pages, 11 figures, 5 tables

Published
2024

4. A general theory to estimate Information transfer in nonlinear systems

Author

Pires, Carlos A., Docquier, David, and Vannitsem, Stéphane

Subjects
Nonlinear Sciences - Chaotic Dynamics
Abstract

A general theory for computing information transfers in nonlinear stochastic systems driven by deterministic forcing and additive and/or multiplicative noises, is presented. It extends the Liang-Kleeman framework of causality inference to nonlinear cases based on information transfer across system variables (Liang, 2016). We present an effective method of computing formulas of the rates of Shannon entropy transfer (RETs) between selected causal and consequential variables, relying on the estimation from data of conditional expectations of the system forcing and their derivatives. Those expectations are approximated by nonlinear differentiable regressions, leading to a much easier and more robust way of computing RETs than the brute-force approach calling for numerical integrals over the state-space and the knowledge of the multivariate probability density of the system. The approach is fully adapted to the case where no model equations are available, starting with a nonlinear model fitting from data of the consequential variables, and the subsequent application of method to the fitted model. RETs are decomposed into sums of single one-to-one RETs plus synergetic terms (of pure nonlinear nature) accounting for the joint causal effect of groups of variables. State-dependent RET formulas are also introduced, showing where in state-space the entropy transfers and local synergies are more relevant. A comparison of the RETs estimations is performed with previous methods in the context of two models: (i) a model derived from a potential function and (ii) the classical chaotic Lorenz system, both forced by additive and/or multiplicative noises. The analysis demonstrates that the new estimations are robust, cheaper, and less data-demanding, providing evidence of the possibilities and generalizations offered by the method and opening new perspectives on real-world applications., Comment: 51 pages, 7 figures. Submitted to Physica D

Published
2023

9. Climate tipping point interactions and cascades : a review

Author

Wunderling, Nico, von der Heydt, Anna S., Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-Cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan, Falkena, Swinda K. J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman Julius, Willeit, Matteo, Wunderling, Nico, von der Heydt, Anna S., Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-Cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan, Falkena, Swinda K. J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman Julius, and Willeit, Matteo

Abstract

Climate tipping elements are large-scale subsystems of the Earth that may transgress critical thresholds (tipping points) under ongoing global warming, with substantial impacts on the biosphere and human societies. Frequently studied examples of such tipping elements include the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), permafrost, monsoon systems, and the Amazon rainforest. While recent scientific efforts have improved our knowledge about individual tipping elements, the interactions between them are less well understood. Also, the potential of individual tipping events to induce additional tipping elsewhere or stabilize other tipping elements is largely unknown. Here, we map out the current state of the literature on the interactions between climate tipping elements and review the influences between them. To do so, we gathered evidence from model simulations, observations, and conceptual understanding, as well as examples of paleoclimate reconstructions where multi-component or spatially propagating transitions were potentially at play. While uncertainties are large, we find indications that many of the interactions between tipping elements are destabilizing. Therefore, we conclude that tipping elements should not only be studied in isolation, but also more emphasis has to be put on potential interactions. This means that tipping cascades cannot be ruled out on centennial to millennial timescales at global warming levels between 1.5 and 2.0 ∘C or on shorter timescales if global warming surpassed 2.0 ∘C. At these higher levels of global warming, tipping cascades may then include fast tipping elements such as the AMOC or the Amazon rainforest. To address crucial knowledge gaps in tipping element interactions, we propose four strategies combining observation-based approaches, Earth system modeling expertise, computational advances, and expert knowledge.

Published
2024
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10. Climate tipping point interactions and cascades: a review

Author

Marine and Atmospheric Research, Sub Physical Oceanography, Sub Mathematical Modeling, Sub Algemeen Marine & Atmospheric Res, Spatial Ecology and Global Change, Wunderling, Nico, Heydt, Anna S von der, Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline, Lohmann, Johannes Jakob, Roman-Cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John, Chiessi, Cristiano, Coxall, Helen, Docquier, David, Donges, Jonathan, Falkena, Swinda K.J., Klose, Ann Kristin, Obura, David, Rocha, Juan Carlos, Rynders, Stefanie, Steinert, Norman J., Willeit, Matteo, Marine and Atmospheric Research, Sub Physical Oceanography, Sub Mathematical Modeling, Sub Algemeen Marine & Atmospheric Res, Spatial Ecology and Global Change, Wunderling, Nico, Heydt, Anna S von der, Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline, Lohmann, Johannes Jakob, Roman-Cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John, Chiessi, Cristiano, Coxall, Helen, Docquier, David, Donges, Jonathan, Falkena, Swinda K.J., Klose, Ann Kristin, Obura, David, Rocha, Juan Carlos, Rynders, Stefanie, Steinert, Norman J., and Willeit, Matteo

Published
2024

11. Climate tipping point interactions and cascades:a review

Author

Wunderling, Nico, Von Der Heydt, Anna S., Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan F., Falkena, Swinda K. J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman Julius, Willeit, Matteo, Wunderling, Nico, Von Der Heydt, Anna S., Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-cuesta, Rosa Maria, Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan F., Falkena, Swinda K. J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman Julius, and Willeit, Matteo

Published
2024

18. Grounding-line migration in plan-view marine ice-sheet models: results of the ice2sea MISMIP3d intercomparison

Author

Pattyn, Frank, Perichon, Laura, Durand, Gael, Favier, Lionel, Gagliardini, Olivier, Hindmarsh, Richard C.A., Zwinger, Thomas, Albrecht, Torsten, Cornford, Stephen, Docquier, David, Furst, Johannes J, Goldberg, Daniel, Gudmundsson, G. Hilmar, Humbert, Angelika, Hutten, Moritz, Huybrechts, Philippe, Jouvet, Guillaume, Kleiner, Thomas, Larour, Eric, Martin, Daniel, Morlighem, Mathieu, Payne, Anthony J, Pollard, David, Ruckamp, Martin, Rybak, Oleg, Seroussi, Helene, Thoma, Malte, and Wilkens, Nina

Subjects
boundary layer, computer simulation, error analysis, ice sheet, modeling, prediction, spatial variation, steady-state equilibrium
Abstract

Predictions of marine ice-sheet behaviour require models able to simulate grounding-line migration. We present results of an intercomparison experiment for plan-view marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no buttressing effects from lateral drag). Perturbation experiments specifying spatial variation in basal sliding parameters permitted the evolution of curved grounding lines, generating buttressing effects. The experiments showed regions of compression and extensional flow across the grounding line, thereby invalidating the boundary layer theory. Steady-state grounding-line positions were found to be dependent on the level of physical model approximation. Resolving grounding lines requires inclusion of membrane stresses, a sufficiently small grid size (

Published
2013

20. Climate tipping point interactions and cascades: A review

Author

Wunderling, Nico, primary, von der Heydt, Anna, additional, Aksenov, Yevgeny, additional, Barker, Stephen, additional, Bastiaansen, Robbin, additional, Brovkin, Victor, additional, Brunetti, Maura, additional, Couplet, Victor, additional, Kleinen, Thomas, additional, Lear, Caroline H., additional, Lohmann, Johannes, additional, Roman-Cuesta, Rosa Maria, additional, Sinet, Sacha, additional, Swingedouw, Didier, additional, Winkelmann, Ricarda, additional, Anand, Pallavi, additional, Barichivich, Jonathan, additional, Bathiany, Sebastian, additional, Baudena, Mara, additional, Bruun, John T., additional, Chiessi, Christiano M., additional, Coxall, Helen K., additional, Docquier, David, additional, Donges, Jonathan F., additional, Falkena, Swinda K. J., additional, Klose, Ann Kristin, additional, Obura, David, additional, Rocha, Juan, additional, Rynders, Stefanie, additional, Steinert, Norman Julius, additional, and Willeit, Matteo, additional

Published
2023
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21. A comparison of two causal methods in the context of climate analyses.

Author

Docquier, David, Di Capua, Giorgia, Donner, Reik V., Pires, Carlos A. L., Simon, Amélie, and Vannitsem, Stéphane

Subjects
EL Nino, ARCTIC oscillation, STATISTICAL correlation
Abstract

Correlation does not necessarily imply causation, and this is why causal methods have been developed to try to disentangle true causal links from spurious relationships. In our study, we use two causal methods, namely, the Liang–Kleeman information flow (LKIF) and the Peter and Clark momentary conditional independence (PCMCI) algorithm, and we apply them to four different artificial models of increasing complexity and one real-world case study based on climate indices in the Atlantic and Pacific regions. We show that both methods are superior to the classical correlation analysis, especially in removing spurious links. LKIF and PCMCI display some strengths and weaknesses for the three simplest models, with LKIF performing better with a smaller number of variables and with PCMCI being best with a larger number of variables. Detecting causal links from the fourth model is more challenging as the system is nonlinear and chaotic. For the real-world case study with climate indices, both methods present some similarities and differences at monthly timescale. One of the key differences is that LKIF identifies the Arctic Oscillation (AO) as the largest driver, while the El Niño–Southern Oscillation (ENSO) is the main influencing variable for PCMCI. More research is needed to confirm these links, in particular including nonlinear causal methods. [ABSTRACT FROM AUTHOR]

Published
2024
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25. Global Tipping Points Report 2023: Ch1.5: Climate tipping point interactions and cascades.

Author

Wunderling, Nico, von der Heydt, Anna, Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-Cuesta, Rosa M., Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan F., Falkena, Swinda K.J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman J., Willeit, Matteo, Wunderling, Nico, von der Heydt, Anna, Aksenov, Yevgeny, Barker, Stephen, Bastiaansen, Robbin, Brovkin, Victor, Brunetti, Maura, Couplet, Victor, Kleinen, Thomas, Lear, Caroline H., Lohmann, Johannes, Roman-Cuesta, Rosa M., Sinet, Sacha, Swingedouw, Didier, Winkelmann, Ricarda, Anand, Pallavi, Barichivich, Jonathan, Bathiany, Sebastian, Baudena, Mara, Bruun, John T., Chiessi, Cristiano M., Coxall, Helen K., Docquier, David, Donges, Jonathan F., Falkena, Swinda K.J., Klose, Ann Kristin, Obura, David, Rocha, Juan, Rynders, Stefanie, Steinert, Norman J., and Willeit, Matteo

Abstract

This chapter reviews interactions between climate tipping systems and assesses the potential risk of cascading effects. After a definition of tipping system interactions, we map out the current state of the literature on specific interactions between climate tipping systems that may be important for the overall stability of the climate system. For this, we gather evidence from model simulations, observations and conceptual understanding, as well as archetypal examples of palaeoclimate reconstructions where propagating transitions were potentially at play. This chapter concludes by identifying crucial knowledge gaps in tipping system interactions that should be resolved in order to improve risk assessments of cascading transitions under future climate change scenarios.

Published
2023

26. A comparison of two causal methods in the context of climate analyses.

Author

Docquier, David, Capua, Giorgia Di, Donner, Reik V., Pires, Carlos A. L., Simon, Amélie, and Vannitsem, Stéphane

Subjects
EL Nino, ARCTIC oscillation, STATISTICAL correlation
Abstract

Correlation does not necessarily imply causation, and this is why causal methods have been developed to try to disentangle true causal links from spurious relationships. In our study, we use two causal methods, namely the Liang-Kleeman information flow (LKIF) and the Peter and Clark momentary conditional independence (PCMCI) algorithm, and apply them to four different artificial models of increasing complexity and one real-case study based on climate indices in the North Atlantic and North Pacific. We show that both methods are superior to the classical correlation analysis, especially in removing spurious links. LKIF and PCMCI display some strengths and weaknesses for the three simplest models, with LKIF performing better with a smaller number of variables, and PCMCI being best with a larger number of variables. Detecting causal links from the fourth model is more challenging as the system is nonlinear and chaotic. For the real-case study with climate indices, both methods present some similarities and differences at monthly time scale. One of the key differences is that LKIF identifies the Arctic Oscillation (AO) as the largest driver, while El Niño-Southern Oscillation (ENSO) is the main influencing variable for PCMCI. More research is needed to confirm these links, in particular including nonlinear causal methods. [ABSTRACT FROM AUTHOR]

Published
2023
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30. Quantifying climate feedbacks in polar regions

Author

Goosse, Hugues, Kay, Jennifer E., Armour, Kyle C., Bodas-Salcedo, Alejandro, Chepfer, Helene, Docquier, David, Jonko, Alexandra, Kushner, Paul J., Lecomte, Olivier, Massonnet, François, Park, Hyo-Seok, Pithan, Felix, Svensson, Gunilla, and Vancoppenolle, Martin

Published
2018
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32. The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

Author

Döscher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes-Franco, Ramon, Gröger, Matthias, Hardenberg, Jost, Hieronymus, Jenny, Karami, M. Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, François, Ménégoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Tintó Prims, Oriol, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrödner, Roland, Serva, Federico, Sicardi, Valentina, Madsen, Marianne Sloth, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Wårlind, David, Willén, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbós, Xavier, Zhang, Qiong, Döscher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes-Franco, Ramon, Gröger, Matthias, Hardenberg, Jost, Hieronymus, Jenny, Karami, M. Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, François, Ménégoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Tintó Prims, Oriol, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrödner, Roland, Serva, Federico, Sicardi, Valentina, Madsen, Marianne Sloth, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Wårlind, David, Willén, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbós, Xavier, and Zhang, Qiong

Abstract

The Earth system model EC-Earth3 for contributions to CMIP6 is documented here, with its flexible coupling framework, major model configurations, a methodology for ensuring the simulations are comparable across different high-performance computing (HPC) systems, and with the physical performance of base configurations over the historical period. The variety of possible configurations and sub-models reflects the broad interests in the EC-Earth community. EC-Earth3 key performance metrics demonstrate physical behavior and biases well within the frame known from recent CMIP models. With improved physical and dynamic features, new Earth system model (ESM) components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond.

Published
2022
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33. The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

Author

Doescher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes Franco, Ramon, Groger, Matthias, Hardenberg, Jost, V, Hieronymus, Jenny, Karami, Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, Francois, Menegoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Tinto Prims, Oriol, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrodner, Roland, Serva, Federico, Sicardi, Valentina, Madsen, Marianne Sloth, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Warlind, David, Willen, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbos, Xavier, Zhang, Qiong, Doescher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes Franco, Ramon, Groger, Matthias, Hardenberg, Jost, V, Hieronymus, Jenny, Karami, Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, Francois, Menegoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Tinto Prims, Oriol, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrodner, Roland, Serva, Federico, Sicardi, Valentina, Madsen, Marianne Sloth, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Warlind, David, Willen, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbos, Xavier, and Zhang, Qiong

Published
2022
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34. Summertime changes in climate extremes over the peripheral Arctic regions after a sudden sea ice retreat

Author

UCL - SST/ELI/ELIC - Earth & Climate, Delhaye, Steve, Fichefet, Thierry, Massonnet, François, Docquier, David, Msadek, Rym, Chripko, Svenya, Roberts, Christopher, Keeley, Sarah, Retish,Senan, UCL - SST/ELI/ELIC - Earth & Climate, Delhaye, Steve, Fichefet, Thierry, Massonnet, François, Docquier, David, Msadek, Rym, Chripko, Svenya, Roberts, Christopher, Keeley, Sarah, and Retish,Senan

Abstract

The retreat of Arctic sea ice is frequently considered to be a possible driver of changes in climate extremes in the Arctic and possibly down to mid-latitudes. However, it remains unclear how the atmosphere will respond to a near-total retreat of summer Arctic sea ice, a reality that might occur in the foreseeable future. This study explores this question by conducting sensitivity experiments with two global coupled climate models run at two different horizontal resolutions to investigate the change in temperature and precipitation extremes during summer over peripheral Arctic regions following a sudden reduction in summer Arctic sea ice cover. An increase in frequency and persistence of maximum surface air temperature is found in all peripheral Arctic regions during the summer, when sea ice loss occurs. For each 1×106 km2 of Arctic sea ice extent reduction, the absolute frequency of days exceeding the surface air temperature of the climatological 90th percentile increases by ∼ 4 % over the Svalbard area, and the duration of warm spells increases by ∼ 1 d per month over the same region. Furthermore, we find that the 10th percentile of surface daily air temperature increases more than the 90th percentile, leading to a weakened diurnal cycle of surface air temperature. Finally, an increase in extreme precipitation, which is less robust than the increase in extreme temperatures, is found in all regions in summer. These findings suggest that a sudden retreat of summer Arctic sea ice clearly impacts the extremes in maximum surface air temperature and precipitation over the peripheral Arctic regions with the largest influence over inhabited islands such as Svalbard or northern Canada. Nonetheless, even with a large sea ice reduction in regions close to the North Pole, the local precipitation response is relatively small compared to internal climate variability.

Published
2022

36. The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

Author

UCL - SST/ELI/ELIC - Earth & Climate, Döscher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes-Franco, Ramon, Gröger, Matthias, v. Hardenberg, Jost, Hieronymus, Jenny, Karami, M. Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, François, Ménégoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Prims, Oriol Tintó, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrödner, Roland, Serva, Federico, Sicardi, Valentina, Sloth Madsen, Marianne, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Wårlind, David, Willén, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbós, Xavier, Zhang, Qiong, UCL - SST/ELI/ELIC - Earth & Climate, Döscher, Ralf, Acosta, Mario, Alessandri, Andrea, Anthoni, Peter, Arsouze, Thomas, Bergman, Tommi, Bernardello, Raffaele, Boussetta, Souhail, Caron, Louis-Philippe, Carver, Glenn, Castrillo, Miguel, Catalano, Franco, Cvijanovic, Ivana, Davini, Paolo, Dekker, Evelien, Doblas-Reyes, Francisco J., Docquier, David, Echevarria, Pablo, Fladrich, Uwe, Fuentes-Franco, Ramon, Gröger, Matthias, v. Hardenberg, Jost, Hieronymus, Jenny, Karami, M. Pasha, Keskinen, Jukka-Pekka, Koenigk, Torben, Makkonen, Risto, Massonnet, François, Ménégoz, Martin, Miller, Paul A., Moreno-Chamarro, Eduardo, Nieradzik, Lars, van Noije, Twan, Nolan, Paul, O'Donnell, Declan, Ollinaho, Pirkka, van den Oord, Gijs, Ortega, Pablo, Prims, Oriol Tintó, Ramos, Arthur, Reerink, Thomas, Rousset, Clement, Ruprich-Robert, Yohan, Le Sager, Philippe, Schmith, Torben, Schrödner, Roland, Serva, Federico, Sicardi, Valentina, Sloth Madsen, Marianne, Smith, Benjamin, Tian, Tian, Tourigny, Etienne, Uotila, Petteri, Vancoppenolle, Martin, Wang, Shiyu, Wårlind, David, Willén, Ulrika, Wyser, Klaus, Yang, Shuting, Yepes-Arbós, Xavier, and Zhang, Qiong

Published
2022

38. The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

Author

Döscher, Ralf, primary, Acosta, Mario, additional, Alessandri, Andrea, additional, Anthoni, Peter, additional, Arsouze, Thomas, additional, Bergman, Tommi, additional, Bernardello, Raffaele, additional, Boussetta, Souhail, additional, Caron, Louis-Philippe, additional, Carver, Glenn, additional, Castrillo, Miguel, additional, Catalano, Franco, additional, Cvijanovic, Ivana, additional, Davini, Paolo, additional, Dekker, Evelien, additional, Doblas-Reyes, Francisco J., additional, Docquier, David, additional, Echevarria, Pablo, additional, Fladrich, Uwe, additional, Fuentes-Franco, Ramon, additional, Gröger, Matthias, additional, v. Hardenberg, Jost, additional, Hieronymus, Jenny, additional, Karami, M. Pasha, additional, Keskinen, Jukka-Pekka, additional, Koenigk, Torben, additional, Makkonen, Risto, additional, Massonnet, François, additional, Ménégoz, Martin, additional, Miller, Paul A., additional, Moreno-Chamarro, Eduardo, additional, Nieradzik, Lars, additional, van Noije, Twan, additional, Nolan, Paul, additional, O'Donnell, Declan, additional, Ollinaho, Pirkka, additional, van den Oord, Gijs, additional, Ortega, Pablo, additional, Prims, Oriol Tintó, additional, Ramos, Arthur, additional, Reerink, Thomas, additional, Rousset, Clement, additional, Ruprich-Robert, Yohan, additional, Le Sager, Philippe, additional, Schmith, Torben, additional, Schrödner, Roland, additional, Serva, Federico, additional, Sicardi, Valentina, additional, Sloth Madsen, Marianne, additional, Smith, Benjamin, additional, Tian, Tian, additional, Tourigny, Etienne, additional, Uotila, Petteri, additional, Vancoppenolle, Martin, additional, Wang, Shiyu, additional, Wårlind, David, additional, Willén, Ulrika, additional, Wyser, Klaus, additional, Yang, Shuting, additional, Yepes-Arbós, Xavier, additional, and Zhang, Qiong, additional

Published
2022
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44. Interactions between ocean heat budget terms in HighResMIP climate models measured by the rate of information transfer.

Author

Docquier, David, Vannitsem, Stéphane, Bellucci, Alessio, and Frankignoul, Claude

Subjects
HEAT budget (Geophysics), ATMOSPHERIC models, HEAT flux, THERMODYNAMICS, CLIMATOLOGY
Abstract

The Liang-Kleeman rate of information transfer is used to quantify interactions between the different terms of the ocean heat budget at monthly time scale over the period 1988–2017 in three coupled global climate models participating in the High Resolution Model Intercomparison Project (HighResMIP), as well as in the Ocean Reanalysis System 5 (ORAS5). In particular, we focus on the influences of ocean heat transport convergence (dynamical influence) and net surface heat flux (thermodynamical influence) on ocean heat content tendency. At least two different configurations are used for each model, allowing to investigate the impact of ocean resolution on these causal relationships. A very small number of regions with a dynamical influence is found at high ocean resolution (≤ 0.25°) and ORAS5 reanalysis when considering the upper 50 m, while a thermodynamical influence is present in a large number of regions. The number of regions with a dynamical influence increases when taking into account the upper 300 m and becomes comparable to the thermodynamical influence. Interestingly, low-resolution model configurations (1° in the ocean) show a much larger number of regions with a significant dynamical influence for both depth integrations (upper 50 m and 300 m) compared to high-resolution model configurations. The reason for the large difference in dynamical influence between low and high resolutions partly comes from the spatial distribution of ocean velocity field, which is highly variable at high resolution, leading to a smaller dynamical influence. High resolution is therefore key in representing realistically the causal interactions between the ocean and atmosphere. [ABSTRACT FROM AUTHOR]

Published
2022
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46. An inter-comparison of the mass budget of the Arctic sea ice in CMIP6 models

Author

Keen, Ann, Blockley, Ed, Bailey, David A., Debernard, Jens Boldingh, Bushuk, Mitchell, Delhaye, Steve, Docquier, David, Feltham, Daniel, Massonnet, Francois, O'Farrell, Siobhan, Ponsoni, Leandro, Rodriguez, Jose M., Schroeder, David, Swart, Neil, Toyoda, Takahiro, Tsujino, Hiroyuki, Vancoppenolle, Martin, Wyser, Klaus, Keen, Ann, Blockley, Ed, Bailey, David A., Debernard, Jens Boldingh, Bushuk, Mitchell, Delhaye, Steve, Docquier, David, Feltham, Daniel, Massonnet, Francois, O'Farrell, Siobhan, Ponsoni, Leandro, Rodriguez, Jose M., Schroeder, David, Swart, Neil, Toyoda, Takahiro, Tsujino, Hiroyuki, Vancoppenolle, Martin, and Wyser, Klaus

Published
2021
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48. An inter-comparison of the mass budget of the Arctic sea ice in CMIP6 models

Author

UCL - SST/ELI/ELIC - Earth & Climate, Keen, Ann, Blockley, Ed, Bailey, David A., Boldingh Debernard, Jens, Bushuk, Mitchell, Delhaye, Steve, Docquier, David, Feltham, Daniel, Massonnet, François, O'Farrell, Siobhan, Ponsoni, Leandro, Rodriguez, José M., Schroeder, David, Swart, Neil, Toyoda, Takahiro, Tsujino, Hiroyuki, Vancoppenolle, Martin, Wyser, Klaus, UCL - SST/ELI/ELIC - Earth & Climate, Keen, Ann, Blockley, Ed, Bailey, David A., Boldingh Debernard, Jens, Bushuk, Mitchell, Delhaye, Steve, Docquier, David, Feltham, Daniel, Massonnet, François, O'Farrell, Siobhan, Ponsoni, Leandro, Rodriguez, José M., Schroeder, David, Swart, Neil, Toyoda, Takahiro, Tsujino, Hiroyuki, Vancoppenolle, Martin, and Wyser, Klaus

Abstract

We compare the mass budget of the Arctic sea ice for 15 models submitted to the latest Coupled Model Intercomparison Project (CMIP6), using new diagnostics that have not been available for previous model inter-comparisons. These diagnostics allow us to look beyond the standard metrics of ice cover and thickness to compare the processes of sea ice growth and loss in climate models in a more detailed way than has previously been possible. For the 1960–1989 multi-model mean, the dominant processes causing annual ice growth are basal growth and frazil ice formation, which both occur during the winter. The main processes by which ice is lost are basal melting, top melting and advection of ice out of the Arctic. The first two processes occur in summer, while the latter process is present all year. The sea ice budgets for individual models are strikingly similar overall in terms of the major processes causing ice growth and loss and in terms of the time of year during which each process is important. However, there are also some key differences between the models, and we have found a number of relationships between model formulation and components of the ice budget that hold for all or most of the CMIP6 models considered here. The relative amounts of frazil and basal ice formation vary between the models, and the amount of frazil ice formation is strongly dependent on the value chosen for the minimum frazil ice thickness. There are also differences in the relative amounts of top and basal melting, potentially dependent on how much shortwave radiation can penetrate through the sea ice into the ocean. For models with prognostic melt ponds, the choice of scheme may affect the amount of basal growth, basal melt and top melt, and the choice of thermodynamic scheme is important in determining the amount of basal growth and top melt. As the ice cover and mass decline during the 21st century, we see a shift in the timing of the top and basal melting in the multi-model mean, with m

Published
2021

49. Impact of ocean heat transport on the Arctic sea-ice decline: a model study with EC-Earth3

Author

Barcelona Supercomputing Center, Docquier, David, Koenigk, Torben, Fuentes-Franco, Ramon, Pasha Karami, Mehdi, Ruprich-Robert, Yohan, Barcelona Supercomputing Center, Docquier, David, Koenigk, Torben, Fuentes-Franco, Ramon, Pasha Karami, Mehdi, and Ruprich-Robert, Yohan

Abstract

The recent increase in Atlantic and Pacific ocean heat transports has led to a decrease in Arctic sea-ice area and volume. As the respective contributions from both oceans in driving sea-ice loss is still uncertain, our study explores this. We use the EC-Earth3 coupled global climate model and perform different sensitivity experiments to gain insights into the relationships between ocean heat transport and Arctic sea ice. In these model experiments, the sea-surface temperature is artificially increased in different regions of the North Atlantic and North Pacific Oceans and with different levels of warming. All the experiments lead to enhanced ocean heat transport, and consequently to a decrease in Arctic sea-ice area and volume. We show that the wider the domain in which the sea-surface temperature is increased and the larger the level of warming, the larger the increase in ocean heat transport and the stronger the decrease in Arctic sea-ice area and volume. We also find that for a same amount of ocean heat transport increase, the reductions in Arctic sea-ice area and volume are stronger when the sea-surface temperature increase is imposed in the North Pacific, compared to the North Atlantic. This is explained by the lower-salinity water at the Bering Strait and atmospheric warming of the North Atlantic Ocean in the Pacific experiments. Finally, we find that the sea-ice loss is mainly driven by reduced basal growth along the sea-ice edge and enhanced basal melt in the Central Arctic. This confirms that the ocean heat transport is the primary driver of Arctic sea-ice loss in our experiments., DD is supported by the OSeaIce project (https://cordis.europa.eu/project/id/834493), which has received funding from the European Union’s (EU) Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 834493. TK and RFF are funded by the EU Horizon 2020 PRIMAVERA project, grant agreement No. 641727. MPK acknowledges support from the NordForsk research program Arctic Climate Predictions: Pathways to Resilient, Sustainable Societies (ARCPATH, No. 76654). YRR was funded by the EU Horizon 2020 research and innovation programme in the framework of the Marie Sklodowska-Curie grant INADEC (grant agreement No. 800154)., Peer Reviewed, Postprint (published version)

Published
2021

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