Articles | Volume 17, issue 2
https://doi.org/10.5194/cp-17-615-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-17-615-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Mar 2021
Research article |
| 11 Mar 2021
| 11 Mar 2021
Simulated stability of the Atlantic Meridional Overturning Circulation during the Last Glacial Maximum
Frerk Pöppelmeier
CORRESPONDING AUTHOR
Climate and Environmental Physics, Physics Institute and Oeschger
Center for Climate Change Research, University of Bern, 3012 Bern,
Switzerland
Jeemijn Scheen
Climate and Environmental Physics, Physics Institute and Oeschger
Center for Climate Change Research, University of Bern, 3012 Bern,
Switzerland
Aurich Jeltsch-Thömmes
Climate and Environmental Physics, Physics Institute and Oeschger
Center for Climate Change Research, University of Bern, 3012 Bern,
Switzerland
Thomas F. Stocker
Climate and Environmental Physics, Physics Institute and Oeschger
Center for Climate Change Research, University of Bern, 3012 Bern,
Switzerland
Related authors
Markus Adloff, Aurich Jeltsch-Thömmes, Frerk Pöppelmeier, Thomas F. Stocker, and Fortunat Joos
Clim. Past, 21, 571–592, https://doi.org/10.5194/cp-21-571-2025, https://doi.org/10.5194/cp-21-571-2025, 2025
Short summary
Short summary
We simulated how different processes affected the carbon cycle over the last eight glacial cycles. We found that the effects of interactive marine sediments enlarge the carbon fluxes that result from these processes, especially in the ocean, and alter various proxy signals. We provide an assessment of the directions of regional and global proxy changes that might be expected in response to different glacial–interglacial Earth system changes in the presence of interactive marine sediments.
Markus Adloff, Frerk Pöppelmeier, Aurich Jeltsch-Thömmes, Thomas F. Stocker, and Fortunat Joos
Clim. Past, 20, 1233–1250, https://doi.org/10.5194/cp-20-1233-2024, https://doi.org/10.5194/cp-20-1233-2024, 2024
Short summary
Short summary
The Atlantic Meridional Overturning Circulation (AMOC) is an ocean current that transports heat into the North Atlantic. Over the ice age cycles, AMOC strength and its spatial pattern varied. We tested the role of heat forcing for these AMOC changes by simulating the temperature changes of the last eight glacial cycles. In our model, AMOC shifts between four distinct circulation modes caused by heat and salt redistributions that reproduce reconstructed long-term North Atlantic SST changes.
Suzanne Robinson, Ruza F. Ivanovic, Lauren J. Gregoire, Julia Tindall, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, Kazuyo Tachikawa, and Paul J. Valdes
Geosci. Model Dev., 16, 1231–1264, https://doi.org/10.5194/gmd-16-1231-2023, https://doi.org/10.5194/gmd-16-1231-2023, 2023
Short summary
Short summary
We present the implementation of neodymium (Nd) isotopes into the ocean model of FAMOUS (Nd v1.0). Nd fluxes from seafloor sediment and incorporation of Nd onto sinking particles represent the major global sources and sinks, respectively. However, model–data mismatch in the North Pacific and northern North Atlantic suggest that certain reactive components of the sediment interact the most with seawater. Our results are important for interpreting Nd isotopes in terms of ocean circulation.
Suzanne Robinson, Ruza Ivanovic, Lauren Gregoire, Lachlan Astfalck, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, and Kazuyo Tachikawa
EGUsphere, https://doi.org/10.5194/egusphere-2022-937, https://doi.org/10.5194/egusphere-2022-937, 2022
Preprint archived
Short summary
Short summary
The neodymium (Nd) isotope (εNd) scheme in the ocean model of FAMOUS is used to explore a benthic Nd flux to seawater. Our results demonstrate that sluggish modern Pacific waters are sensitive to benthic flux alterations, whereas the well-ventilated North Atlantic displays a much weaker response. In closing, there are distinct regional differences in how seawater acquires its εNd signal, in part relating to the complex interactions of Nd addition and water advection.
Frerk Pöppelmeier, David J. Janssen, Samuel L. Jaccard, and Thomas F. Stocker
Biogeosciences, 18, 5447–5463, https://doi.org/10.5194/bg-18-5447-2021, https://doi.org/10.5194/bg-18-5447-2021, 2021
Short summary
Short summary
Chromium (Cr) is a redox-sensitive element that holds promise as a tracer of ocean oxygenation and biological activity. We here implemented the oxidation states Cr(III) and Cr(VI) in the Bern3D model to investigate the processes that shape the global Cr distribution. We find a Cr ocean residence time of 5–8 kyr and that the benthic source dominates the tracer budget. Further, regional model–data mismatches suggest strong Cr removal in oxygen minimum zones and a spatially variable benthic source.
Markus Adloff, Aurich Jeltsch-Thömmes, Frerk Pöppelmeier, Thomas F. Stocker, and Fortunat Joos
Clim. Past, 21, 571–592, https://doi.org/10.5194/cp-21-571-2025, https://doi.org/10.5194/cp-21-571-2025, 2025
Short summary
Short summary
We simulated how different processes affected the carbon cycle over the last eight glacial cycles. We found that the effects of interactive marine sediments enlarge the carbon fluxes that result from these processes, especially in the ocean, and alter various proxy signals. We provide an assessment of the directions of regional and global proxy changes that might be expected in response to different glacial–interglacial Earth system changes in the presence of interactive marine sediments.
Jakob Schwander, Thomas F. Stocker, Remo Walther, Samuel Marending, Tobias Erhardt, Chantal Zeppenfeld, and Jürg Jost
The Cryosphere, 18, 5613–5617, https://doi.org/10.5194/tc-18-5613-2024, https://doi.org/10.5194/tc-18-5613-2024, 2024
Short summary
Short summary
The RADIX (Rapid Access Drilling and Ice eXtraction) optical dust logger is part of the exploratory 20 mm drilling system at the University of Bern and is inserted into the hole after drilling. Temperature and attitude sensors were successfully tested but not the dust sensor, as no RADIX hole reached the required bubble-free ice. In 2023, we tested the logger with an adapter for the deep borehole of the East Greenland Ice-core Project and obtained a good Late Glacial–Early Holocene dust record.
Christian Wirths, Thomas F. Stocker, and Johannes C. R. Sutter
The Cryosphere, 18, 4435–4462, https://doi.org/10.5194/tc-18-4435-2024, https://doi.org/10.5194/tc-18-4435-2024, 2024
Short summary
Short summary
We investigated the influence of several regional climate models on the Antarctic Ice Sheet when applied as forcing for the Parallel Ice Sheet Model (PISM). Our study shows that the choice of regional climate model forcing results in uncertainties of around a tenth of those in future sea level rise projections and also affects the extent of grounding line retreat in West Antarctica.
Timothée Bourgeois, Olivier Torres, Friederike Fröb, Aurich Jeltsch-Thömmes, Giang T. Tran, Jörg Schwinger, Thomas L. Frölicher, Jean Negrel, David Keller, Andreas Oschlies, Laurent Bopp, and Fortunat Joos
EGUsphere, https://doi.org/10.5194/egusphere-2024-2768, https://doi.org/10.5194/egusphere-2024-2768, 2024
Short summary
Short summary
Anthropogenic greenhouse gas emissions significantly impact ocean ecosystems through climate change and acidification, leading to either progressive or abrupt changes. This study maps the crossing of physical and ecological limits for various ocean impact metrics under three emission scenarios. Using Earth system models, we identify when these limits are exceeded, highlighting the urgent need for ambitious climate action to safeguard the world's oceans and ecosystems.
Hanqin Tian, Naiqing Pan, Rona L. Thompson, Josep G. Canadell, Parvadha Suntharalingam, Pierre Regnier, Eric A. Davidson, Michael Prather, Philippe Ciais, Marilena Muntean, Shufen Pan, Wilfried Winiwarter, Sönke Zaehle, Feng Zhou, Robert B. Jackson, Hermann W. Bange, Sarah Berthet, Zihao Bian, Daniele Bianchi, Alexander F. Bouwman, Erik T. Buitenhuis, Geoffrey Dutton, Minpeng Hu, Akihiko Ito, Atul K. Jain, Aurich Jeltsch-Thömmes, Fortunat Joos, Sian Kou-Giesbrecht, Paul B. Krummel, Xin Lan, Angela Landolfi, Ronny Lauerwald, Ya Li, Chaoqun Lu, Taylor Maavara, Manfredi Manizza, Dylan B. Millet, Jens Mühle, Prabir K. Patra, Glen P. Peters, Xiaoyu Qin, Peter Raymond, Laure Resplandy, Judith A. Rosentreter, Hao Shi, Qing Sun, Daniele Tonina, Francesco N. Tubiello, Guido R. van der Werf, Nicolas Vuichard, Junjie Wang, Kelley C. Wells, Luke M. Western, Chris Wilson, Jia Yang, Yuanzhi Yao, Yongfa You, and Qing Zhu
Earth Syst. Sci. Data, 16, 2543–2604, https://doi.org/10.5194/essd-16-2543-2024, https://doi.org/10.5194/essd-16-2543-2024, 2024
Short summary
Short summary
Atmospheric concentrations of nitrous oxide (N2O), a greenhouse gas 273 times more potent than carbon dioxide, have increased by 25 % since the preindustrial period, with the highest observed growth rate in 2020 and 2021. This rapid growth rate has primarily been due to a 40 % increase in anthropogenic emissions since 1980. Observed atmospheric N2O concentrations in recent years have exceeded the worst-case climate scenario, underscoring the importance of reducing anthropogenic N2O emissions.
Markus Adloff, Frerk Pöppelmeier, Aurich Jeltsch-Thömmes, Thomas F. Stocker, and Fortunat Joos
Clim. Past, 20, 1233–1250, https://doi.org/10.5194/cp-20-1233-2024, https://doi.org/10.5194/cp-20-1233-2024, 2024
Short summary
Short summary
The Atlantic Meridional Overturning Circulation (AMOC) is an ocean current that transports heat into the North Atlantic. Over the ice age cycles, AMOC strength and its spatial pattern varied. We tested the role of heat forcing for these AMOC changes by simulating the temperature changes of the last eight glacial cycles. In our model, AMOC shifts between four distinct circulation modes caused by heat and salt redistributions that reproduce reconstructed long-term North Atlantic SST changes.
Bjorn Stevens, Stefan Adami, Tariq Ali, Hartwig Anzt, Zafer Aslan, Sabine Attinger, Jaana Bäck, Johanna Baehr, Peter Bauer, Natacha Bernier, Bob Bishop, Hendryk Bockelmann, Sandrine Bony, Guy Brasseur, David N. Bresch, Sean Breyer, Gilbert Brunet, Pier Luigi Buttigieg, Junji Cao, Christelle Castet, Yafang Cheng, Ayantika Dey Choudhury, Deborah Coen, Susanne Crewell, Atish Dabholkar, Qing Dai, Francisco Doblas-Reyes, Dale Durran, Ayoub El Gaidi, Charlie Ewen, Eleftheria Exarchou, Veronika Eyring, Florencia Falkinhoff, David Farrell, Piers M. Forster, Ariane Frassoni, Claudia Frauen, Oliver Fuhrer, Shahzad Gani, Edwin Gerber, Debra Goldfarb, Jens Grieger, Nicolas Gruber, Wilco Hazeleger, Rolf Herken, Chris Hewitt, Torsten Hoefler, Huang-Hsiung Hsu, Daniela Jacob, Alexandra Jahn, Christian Jakob, Thomas Jung, Christopher Kadow, In-Sik Kang, Sarah Kang, Karthik Kashinath, Katharina Kleinen-von Königslöw, Daniel Klocke, Uta Kloenne, Milan Klöwer, Chihiro Kodama, Stefan Kollet, Tobias Kölling, Jenni Kontkanen, Steve Kopp, Michal Koran, Markku Kulmala, Hanna Lappalainen, Fakhria Latifi, Bryan Lawrence, June Yi Lee, Quentin Lejeun, Christian Lessig, Chao Li, Thomas Lippert, Jürg Luterbacher, Pekka Manninen, Jochem Marotzke, Satoshi Matsouoka, Charlotte Merchant, Peter Messmer, Gero Michel, Kristel Michielsen, Tomoki Miyakawa, Jens Müller, Ramsha Munir, Sandeep Narayanasetti, Ousmane Ndiaye, Carlos Nobre, Achim Oberg, Riko Oki, Tuba Özkan-Haller, Tim Palmer, Stan Posey, Andreas Prein, Odessa Primus, Mike Pritchard, Julie Pullen, Dian Putrasahan, Johannes Quaas, Krishnan Raghavan, Venkatachalam Ramaswamy, Markus Rapp, Florian Rauser, Markus Reichstein, Aromar Revi, Sonakshi Saluja, Masaki Satoh, Vera Schemann, Sebastian Schemm, Christina Schnadt Poberaj, Thomas Schulthess, Cath Senior, Jagadish Shukla, Manmeet Singh, Julia Slingo, Adam Sobel, Silvina Solman, Jenna Spitzer, Philip Stier, Thomas Stocker, Sarah Strock, Hang Su, Petteri Taalas, John Taylor, Susann Tegtmeier, Georg Teutsch, Adrian Tompkins, Uwe Ulbrich, Pier-Luigi Vidale, Chien-Ming Wu, Hao Xu, Najibullah Zaki, Laure Zanna, Tianjun Zhou, and Florian Ziemen
Earth Syst. Sci. Data, 16, 2113–2122, https://doi.org/10.5194/essd-16-2113-2024, https://doi.org/10.5194/essd-16-2113-2024, 2024
Short summary
Short summary
To manage Earth in the Anthropocene, new tools, new institutions, and new forms of international cooperation will be required. Earth Virtualization Engines is proposed as an international federation of centers of excellence to empower all people to respond to the immense and urgent challenges posed by climate change.
Luke Skinner, Francois Primeau, Aurich Jeltsch-Thömmes, Fortunat Joos, Peter Köhler, and Edouard Bard
Clim. Past, 19, 2177–2202, https://doi.org/10.5194/cp-19-2177-2023, https://doi.org/10.5194/cp-19-2177-2023, 2023
Short summary
Short summary
Radiocarbon is best known as a dating tool, but it also allows us to track CO2 exchange between the ocean and atmosphere. Using decades of data and novel mapping methods, we have charted the ocean’s average radiocarbon ″age” since the last Ice Age. Combined with climate model simulations, these data quantify the ocean’s role in atmospheric CO2 rise since the last Ice Age while also revealing that Earth likely received far more cosmic radiation during the last Ice Age than hitherto believed.
Christoph Heinze, Thorsten Blenckner, Peter Brown, Friederike Fröb, Anne Morée, Adrian L. New, Cara Nissen, Stefanie Rynders, Isabel Seguro, Yevgeny Aksenov, Yuri Artioli, Timothée Bourgeois, Friedrich Burger, Jonathan Buzan, B. B. Cael, Veli Çağlar Yumruktepe, Melissa Chierici, Christopher Danek, Ulf Dieckmann, Agneta Fransson, Thomas Frölicher, Giovanni Galli, Marion Gehlen, Aridane G. González, Melchor Gonzalez-Davila, Nicolas Gruber, Örjan Gustafsson, Judith Hauck, Mikko Heino, Stephanie Henson, Jenny Hieronymus, I. Emma Huertas, Fatma Jebri, Aurich Jeltsch-Thömmes, Fortunat Joos, Jaideep Joshi, Stephen Kelly, Nandini Menon, Precious Mongwe, Laurent Oziel, Sólveig Ólafsdottir, Julien Palmieri, Fiz F. Pérez, Rajamohanan Pillai Ranith, Juliano Ramanantsoa, Tilla Roy, Dagmara Rusiecka, J. Magdalena Santana Casiano, Yeray Santana-Falcón, Jörg Schwinger, Roland Séférian, Miriam Seifert, Anna Shchiptsova, Bablu Sinha, Christopher Somes, Reiner Steinfeldt, Dandan Tao, Jerry Tjiputra, Adam Ulfsbo, Christoph Völker, Tsuyoshi Wakamatsu, and Ying Ye
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-182, https://doi.org/10.5194/bg-2023-182, 2023
Revised manuscript not accepted
Short summary
Short summary
For assessing the consequences of human-induced climate change for the marine realm, it is necessary to not only look at gradual changes but also at abrupt changes of environmental conditions. We summarise abrupt changes in ocean warming, acidification, and oxygen concentration as the key environmental factors for ecosystems. Taking these abrupt changes into account requires greenhouse gas emissions to be reduced to a larger extent than previously thought to limit respective damage.
Robert Mulvaney, Eric W. Wolff, Mackenzie M. Grieman, Helene H. Hoffmann, Jack D. Humby, Christoph Nehrbass-Ahles, Rachael H. Rhodes, Isobel F. Rowell, Frédéric Parrenin, Loïc Schmidely, Hubertus Fischer, Thomas F. Stocker, Marcus Christl, Raimund Muscheler, Amaelle Landais, and Frédéric Prié
Clim. Past, 19, 851–864, https://doi.org/10.5194/cp-19-851-2023, https://doi.org/10.5194/cp-19-851-2023, 2023
Short summary
Short summary
We present an age scale for a new ice core drilled at Skytrain Ice Rise, an ice rise facing the Ronne Ice Shelf in Antarctica. Various measurements in the ice and air phases are used to match the ice core to other Antarctic cores that have already been dated, and a new age scale is constructed. The 651 m ice core includes ice that is confidently dated to 117 000–126 000 years ago, in the last interglacial. Older ice is found deeper down, but there are flow disturbances in the deeper ice.
Jakob Schwander, Thomas F. Stocker, Remo Walther, and Samuel Marending
The Cryosphere, 17, 1151–1164, https://doi.org/10.5194/tc-17-1151-2023, https://doi.org/10.5194/tc-17-1151-2023, 2023
Short summary
Short summary
RADIX (Rapid Access Drilling and Ice eXtraction) is a fast-access ice-drilling system for prospecting future deep-drilling sites on glaciers and polar ice sheets. It consists of a 40 mm rapid firn drill, a 20 mm deep drill and a logger. The maximum depth range of RADIX is 3100 m by design. The nominal drilling speed is on the order of 40 m h-1. The 15 mm diameter logger provides data on the hole inclination and direction and measures temperature and dust in the ice surrounding the borehole.
Suzanne Robinson, Ruza F. Ivanovic, Lauren J. Gregoire, Julia Tindall, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, Kazuyo Tachikawa, and Paul J. Valdes
Geosci. Model Dev., 16, 1231–1264, https://doi.org/10.5194/gmd-16-1231-2023, https://doi.org/10.5194/gmd-16-1231-2023, 2023
Short summary
Short summary
We present the implementation of neodymium (Nd) isotopes into the ocean model of FAMOUS (Nd v1.0). Nd fluxes from seafloor sediment and incorporation of Nd onto sinking particles represent the major global sources and sinks, respectively. However, model–data mismatch in the North Pacific and northern North Atlantic suggest that certain reactive components of the sediment interact the most with seawater. Our results are important for interpreting Nd isotopes in terms of ocean circulation.
Suzanne Robinson, Ruza Ivanovic, Lauren Gregoire, Lachlan Astfalck, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, and Kazuyo Tachikawa
EGUsphere, https://doi.org/10.5194/egusphere-2022-937, https://doi.org/10.5194/egusphere-2022-937, 2022
Preprint archived
Short summary
Short summary
The neodymium (Nd) isotope (εNd) scheme in the ocean model of FAMOUS is used to explore a benthic Nd flux to seawater. Our results demonstrate that sluggish modern Pacific waters are sensitive to benthic flux alterations, whereas the well-ventilated North Atlantic displays a much weaker response. In closing, there are distinct regional differences in how seawater acquires its εNd signal, in part relating to the complex interactions of Nd addition and water advection.
Santos J. González-Rojí, Martina Messmer, Christoph C. Raible, and Thomas F. Stocker
Geosci. Model Dev., 15, 2859–2879, https://doi.org/10.5194/gmd-15-2859-2022, https://doi.org/10.5194/gmd-15-2859-2022, 2022
Short summary
Short summary
Different configurations of physics parameterizations of a regional climate model are tested over southern Peru at fine resolution. The most challenging regions compared to observational data are the slopes of the Andes. Model configurations for Europe and East Africa are not perfectly suitable for southern Peru. The experiment with the Stony Brook University microphysics scheme and the Grell–Freitas cumulus parameterization provides the most accurate results over Madre de Dios.
Tobias Erhardt, Matthias Bigler, Urs Federer, Gideon Gfeller, Daiana Leuenberger, Olivia Stowasser, Regine Röthlisberger, Simon Schüpbach, Urs Ruth, Birthe Twarloh, Anna Wegner, Kumiko Goto-Azuma, Takayuki Kuramoto, Helle A. Kjær, Paul T. Vallelonga, Marie-Louise Siggaard-Andersen, Margareta E. Hansson, Ailsa K. Benton, Louise G. Fleet, Rob Mulvaney, Elizabeth R. Thomas, Nerilie Abram, Thomas F. Stocker, and Hubertus Fischer
Earth Syst. Sci. Data, 14, 1215–1231, https://doi.org/10.5194/essd-14-1215-2022, https://doi.org/10.5194/essd-14-1215-2022, 2022
Short summary
Short summary
The datasets presented alongside this manuscript contain high-resolution concentration measurements of chemical impurities in deep ice cores, NGRIP and NEEM, from the Greenland ice sheet. The impurities originate from the deposition of aerosols to the surface of the ice sheet and are influenced by source, transport and deposition processes. Together, these records contain detailed, multi-parameter records of past climate variability over the last glacial period.
Jiamei Lin, Anders Svensson, Christine S. Hvidberg, Johannes Lohmann, Steffen Kristiansen, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Sune Olander Rasmussen, Eliza Cook, Helle Astrid Kjær, Bo M. Vinther, Hubertus Fischer, Thomas Stocker, Michael Sigl, Matthias Bigler, Mirko Severi, Rita Traversi, and Robert Mulvaney
Clim. Past, 18, 485–506, https://doi.org/10.5194/cp-18-485-2022, https://doi.org/10.5194/cp-18-485-2022, 2022
Short summary
Short summary
We employ acidity records from Greenland and Antarctic ice cores to estimate the emission strength, frequency and climatic forcing for large volcanic eruptions from the last half of the last glacial period. A total of 25 volcanic eruptions are found to be larger than any eruption in the last 2500 years, and we identify more eruptions than obtained from geological evidence. Towards the end of the glacial period, there is a notable increase in volcanic activity observed for Greenland.
Frerk Pöppelmeier, David J. Janssen, Samuel L. Jaccard, and Thomas F. Stocker
Biogeosciences, 18, 5447–5463, https://doi.org/10.5194/bg-18-5447-2021, https://doi.org/10.5194/bg-18-5447-2021, 2021
Short summary
Short summary
Chromium (Cr) is a redox-sensitive element that holds promise as a tracer of ocean oxygenation and biological activity. We here implemented the oxidation states Cr(III) and Cr(VI) in the Bern3D model to investigate the processes that shape the global Cr distribution. We find a Cr ocean residence time of 5–8 kyr and that the benthic source dominates the tracer budget. Further, regional model–data mismatches suggest strong Cr removal in oxygen minimum zones and a spatially variable benthic source.
Loïc Schmidely, Christoph Nehrbass-Ahles, Jochen Schmitt, Juhyeong Han, Lucas Silva, Jinwha Shin, Fortunat Joos, Jérôme Chappellaz, Hubertus Fischer, and Thomas F. Stocker
Clim. Past, 17, 1627–1643, https://doi.org/10.5194/cp-17-1627-2021, https://doi.org/10.5194/cp-17-1627-2021, 2021
Short summary
Short summary
Using ancient gas trapped in polar glaciers, we reconstructed the atmospheric concentrations of methane and nitrous oxide over the penultimate deglaciation to study their response to major climate changes. We show this deglaciation to be characterized by modes of methane and nitrous oxide variability that are also found during the last deglaciation and glacial cycle.
Martina Messmer, Santos J. González-Rojí, Christoph C. Raible, and Thomas F. Stocker
Geosci. Model Dev., 14, 2691–2711, https://doi.org/10.5194/gmd-14-2691-2021, https://doi.org/10.5194/gmd-14-2691-2021, 2021
Short summary
Short summary
Sensitivity experiments with the WRF model are run to find an optimal parameterization setup for precipitation around Mount Kenya at a scale that resolves convection (1 km). Precipitation is compared against many weather stations and gridded observational data sets. Both the temporal correlation of precipitation sums and pattern correlations show that fewer nests lead to a more constrained simulation with higher correlation. The Grell–Freitas cumulus scheme obtains the most accurate results.
Anne L. Morée, Jörg Schwinger, Ulysses S. Ninnemann, Aurich Jeltsch-Thömmes, Ingo Bethke, and Christoph Heinze
Clim. Past, 17, 753–774, https://doi.org/10.5194/cp-17-753-2021, https://doi.org/10.5194/cp-17-753-2021, 2021
Short summary
Short summary
This modeling study of the Last Glacial Maximum (LGM, ~ 21 000 years ago) ocean explores the biological and physical changes in the ocean needed to satisfy marine proxy records, with a focus on the carbon isotope 13C. We estimate that the LGM ocean may have been up to twice as efficient at sequestering carbon and nutrients at depth as compared to preindustrial times. Our work shows that both circulation and biogeochemical changes must have occurred between the LGM and preindustrial times.
Jinhwa Shin, Christoph Nehrbass-Ahles, Roberto Grilli, Jai Chowdhry Beeman, Frédéric Parrenin, Grégory Teste, Amaelle Landais, Loïc Schmidely, Lucas Silva, Jochen Schmitt, Bernhard Bereiter, Thomas F. Stocker, Hubertus Fischer, and Jérôme Chappellaz
Clim. Past, 16, 2203–2219, https://doi.org/10.5194/cp-16-2203-2020, https://doi.org/10.5194/cp-16-2203-2020, 2020
Short summary
Short summary
We reconstruct atmospheric CO2 from the EPICA Dome C ice core during Marine Isotope Stage 6 (185–135 ka) to understand carbon mechanisms under the different boundary conditions of the climate system. The amplitude of CO2 is highly determined by the Northern Hemisphere stadial duration. Carbon dioxide maxima show different lags with respect to the corresponding abrupt CH4 jumps, the latter reflecting rapid warming in the Northern Hemisphere.
Jeemijn Scheen and Thomas F. Stocker
Earth Syst. Dynam., 11, 925–951, https://doi.org/10.5194/esd-11-925-2020, https://doi.org/10.5194/esd-11-925-2020, 2020
Short summary
Short summary
Variability of sea surface temperatures (SST) in 1200–2000 CE is quite well-known, but the history of deep ocean temperatures is not. Forcing an ocean model with these SSTs, we simulate temperatures in the ocean interior. The circulation changes alter the amplitude and timing of deep ocean temperature fluctuations below 2 km depth, e.g. delaying the atmospheric signal by ~ 200 years in the deep Atlantic. Thus ocean circulation changes are shown to be as important as SST changes at these depths.
Anders Svensson, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Thomas Blunier, Sune O. Rasmussen, Bo M. Vinther, Paul Vallelonga, Emilie Capron, Vasileios Gkinis, Eliza Cook, Helle Astrid Kjær, Raimund Muscheler, Sepp Kipfstuhl, Frank Wilhelms, Thomas F. Stocker, Hubertus Fischer, Florian Adolphi, Tobias Erhardt, Michael Sigl, Amaelle Landais, Frédéric Parrenin, Christo Buizert, Joseph R. McConnell, Mirko Severi, Robert Mulvaney, and Matthias Bigler
Clim. Past, 16, 1565–1580, https://doi.org/10.5194/cp-16-1565-2020, https://doi.org/10.5194/cp-16-1565-2020, 2020
Short summary
Short summary
We identify signatures of large bipolar volcanic eruptions in Greenland and Antarctic ice cores during the last glacial period, which allows for a precise temporal alignment of the ice cores. Thereby the exact timing of unexplained, abrupt climatic changes occurring during the last glacial period can be determined in a global context. The study thus provides a step towards a full understanding of elements of the climate system that may also play an important role in the future.
Cited articles
Barker, S., Chen, J., Gong, X., Jonkers, L., Knorr, G., and Thornalley, D.:
Icebergs not the trigger for North Atlantic cold events, Nature, 520,
333–336, https://doi.org/10.1038/nature14330, 2015.
Berger, A. L.: Long-Term Variations of Daily Insolation and Quaternary
Climatic Changes, J. Atmos. Sci., 35, 2362–2367,
https://doi.org/10.1175/1520-0469(1978)035<2362:LTVODI>2.0.CO;2, 1978.
Böhm, E., Lippold, J., Gutjahr, M., Frank, M., Blaser, P., Antz, B.,
Fohlmeister, J., Frank, N., Andersen, M. B., and Deininger, M.: Strong and
deep Atlantic meridional overturning circulation during the last glacial
cycle, Nature, 517, 73–76, https://doi.org/10.1038/nature14059, 2015.
Braconnot, P., Harrison, S. P., Kageyama, M., Bartlein, P. J.,
Masson-Delmotte, V., Abe-Ouchi, A., Otto-Bliesner, B., and Zhao, Y.:
Evaluation of climate models using palaeoclimatic data, Nat. Clim. Change,
2, 417–424, https://doi.org/10.1038/nclimate1456, 2012.
Bradtmiller, L. I., McManus, J. F., and Robinson, L. F.:
231Pa/230Th evidence for a weakened but persistent Atlantic
meridional overturning circulation during Heinrich Stadial 1, Nat. Commun.,
5, 5817, https://doi.org/10.1038/ncomms6817, 2014.
Broecker, W., Bond, G., Klas, M., Clark, E., and McManus, J.: Origin of the
northern Atlantic's Heinrich events, Clim. Dynam., 6, 265–273,
https://doi.org/10.1007/BF00193540, 1992.
Broecker, W. S. and Denton, G. H.: The role of ocean-atmosphere
reorganizations in glacial cycles, Geochim. Cosmochim. Ac., 53,
2465–2501, https://doi.org/10.1016/0016-7037(89)90123-3, 1989.
Clark, P. U., Marshall, S. J., Clarke, G. K. C., Hostetler, S. W.,
Licciardi, J. M., and Teller, J. T.: Freshwater forcing of abrupt climate
change during the last glaciation, Science, 293, 283–287,
https://doi.org/10.1126/science.1062517, 2001.
Condron, A. and Winsor, P.: Meltwater routing and the Younger Dryas, P.
Natl. Acad. Sci. USA, 109, 19928–19933,
https://doi.org/10.1073/pnas.1207381109, 2012.
Curry, W. B. and Oppo, D. W.: Glacial water mass geometry and the
distribution of δ13C of ΣCO2 in the western
Atlantic Ocean, Paleoceanography, 20, 1–12,
https://doi.org/10.1029/2004PA001021, 2005.
Denton, G. H., Anderson, R. F., Toggweiler, J. R., Edwards, R. L., Schaefer,
J. M., and Putnam, A. E.: The last glacial termination, Science, 328,
1652–1656, https://doi.org/10.1126/science.1184119, 2010.
Driesschaert, E., Fichefet, T., Goosse, H., Huybrechts, P., Janssens, I.,
Mouchet, A., Munhoven, G., Brovkin, V., and Weber, S. L.: Modeling the
influence of Greenland ice sheet melting on the Atlantic meridional
overturning circulation during the next millennia, Geophys. Res. Lett.,
34, 1–5, https://doi.org/10.1029/2007GL029516, 2007.
Du, J., Haley, B. A., and Mix, A. C.: Evolution of the Global Overturning
Circulation since the Last Glacial Maximum based on marine authigenic
neodymium isotopes, Quaternary Sci. Rev., 241, 106396,
https://doi.org/10.1016/j.quascirev.2020.106396, 2020.
Duplessy, J. C., Shackleton, N. J., Fairbanks, R. G., Labeyriefi, L., Oppo,
D., Labeyrie, L., Oppo, D., and Kallel, N.: Deepwater source variations
during the last climatic cylce and their impact on the global deepwater
circulation, Paleoceanography, 3, 343–360,
https://doi.org/10.1029/PA003i003p00343, 1988.
Edwards, N. R., Willmott, A. J., and Killworth, P. D.: On the role of
topography and wind stress on the stability of the thermohaline circulation,
J. Phys. Oceanogr., 28, 756–778,
https://doi.org/10.1175/1520-0485(1998)028<0756:OTROTA>2.0.CO;2, 1998.
Egbert, G. D., Ray, R. D., and Bills, B. G.: Numerical modeling of the
global semidiurnal tide in the present day and in the last glacial maximum,
J. Geophys. Res.-Oceans, 109, 1–15,
https://doi.org/10.1029/2003jc001973, 2004.
Evans, H. K. and Hall, I. R.: Deepwater circulation on Blake Outer Ridge
(western North Atlantic) during the Holocene, Younger Dryas, and Last
Glacial Maximum, Geochem. Geophy. Geosyst., 9, 1–19,
https://doi.org/10.1029/2007GC001771, 2008.
Fischer, H., Schmitt, J., Lüthi, D., Stocker, T. F., Tschumi, T.,
Parekh, P., Joos, F., Köhler, P., Völker, C., Gersonde, R.,
Barbante, C., Le Floch, M., Raynaud, D., and Wolff, E.: The role of
Southern Ocean processes in orbital and millennial CO2 variations – A
synthesis, Quaternary Sci. Rev., 29, 193–205,
https://doi.org/10.1016/j.quascirev.2009.06.007, 2010.
Freeman, E., Skinner, L. C., Waelbroeck, C., and Hodell, D.: Radiocarbon
evidence for enhanced respired carbon storage in the Atlantic at the Last
Glacial Maximum, Nat. Commun., 7, 1–8,
https://doi.org/10.1038/ncomms11998, 2016.
Gebbie, G.: How much did Glacial North Atlantic Water shoal?,
Paleoceanography, 29, 190–209, https://doi.org/10.1002/2013PA002557,
2014.
Goes, M., Murphy, L. N., and Clement, A. C.: The Stability of the AMOC
During Heinrich Events Is Not Dependent on the AMOC Strength in an
Intermediate Complexity Earth System Model Ensemble, Paleoceanogr.
Paleoclimatol., 34, 1359–1374, https://doi.org/10.1029/2019PA003580,
2019.
Griffies, S. M.: The Gent–McWilliams Skew Flux, J. Phys. Oceanogr., 28,
831–841, https://doi.org/10.1175/1520-0485(1998)028<0831:TGMSF>2.0.CO;2, 1998.
Hesse, T., Butzin, M., Bickert, T., and Lohmann, G.: A model-data
comparison of δ13C in the glacial Atlantic Ocean,
Paleoceanography, 26, 1–16, https://doi.org/10.1029/2010PA002085, 2011.
Howe, J. N. W., Piotrowski, A. M., Noble, T. L., Mulitza, S., Chiessi, C.
M., and Bayon, G.: North Atlantic Deep Water Production during the Last
Glacial Maximum, Nat. Commun., 7, 11765,
https://doi.org/10.1038/ncomms11765, 2016.
Hu, A., Meehl, G. A., Han, W., Timmermann, A., Otto-Bliesner, B., Liu, Z.,
Washington, W. M., Large, W., Abe-Ouchi, A., Kimoto, M., Lambeck, K., and
Wu, B.: Role of the Bering Strait on the hysteresis of the ocean conveyor
belt circulation and glacial climate stability, P. Natl. Acad. Sci.
USA, 109, 6417–6422, https://doi.org/10.1073/pnas.1116014109, 2012.
Jenkins, W. J., Smethie, W. M., Boyle, E. A., and Cutter, G. A.: Water mass
analysis for the U.S. GEOTRACES (GA03) North Atlantic sections, Deep Sea
Res., 116, 6–20,
https://doi.org/10.1016/j.dsr2.2014.11.018, 2015.
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L.,
Iredell, M., Saha, S., White, G., Wollen, J., Zhu, Y., Chelliah, M.,
Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K. C., Ropelewski, C., Wang,
J., Leetmaa, A., and Joseph, D.: The NCEP NCAR 40-Year Reanalysis
Project. B. Am. Meteorol. Soc., 77, 437–472,
https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2, 1996.
Keigwin, L. D. and Swift, S. A.: Carbon isotope evidence for a northern
source of deep water in the glacial western North Atlantic, P. Natl.
Acad. Sci. USA, 114, 2831–2835,
https://doi.org/10.1073/pnas.1614693114, 2017.
Keigwin, L. D., Klotsko, S., Zhao, N., Reilly, B., Giosan, L., and
Driscoll, N. W.: Deglacial floods in the Beaufort Sea preceded Younger Dryas
cooling, Nat. Geosci., 11, 599–604,
https://doi.org/10.1038/s41561-018-0169-6, 2018.
Lambeck, K., Rouby, H., Purcell, A., Sun, Y., and Sambridge, M.: Sea level
and global ice volumes from the Last Glacial Maximum to the Holocene, P.
Natl. Acad. Sci. USA, 111, 15296–15303,
https://doi.org/10.1073/pnas.1411762111, 2014.
Lehman, S. J. and Keigwin, L. D.: Sudden changes in North Atlantic
circulation during the last deglaciation, Nature, 356, 757–762,
https://doi.org/10.1038/356757a0, 1992.
Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstrof,
S., and Schellnhuber, H. J.: Tipping elements in the Earth System, P.
Natl. Acad. Sci. USA, 105, 1786–1793,
https://doi.org/10.1073/pnas.0911106106, 2008.
Lippold, J., Luo, Y., Francois, R., Allen, S. E., Gherardi, J., Pichat, S.,
Hickey, B., and Schulz, H.: Strength and geometry of the glacial Atlantic
Meridional Overturning Circulation, Nat. Geosci., 5, 813–816,
https://doi.org/10.1038/ngeo1608, 2012.
Lynch-Stieglitz, J.: The Atlantic Meridional Overturning Circulation and
Abrupt Climate Change, Ann. Rev. Mar. Sci., 9, 83–104,
https://doi.org/10.1146/annurev-marine-010816-060415, 2017.
Lynch-Stieglitz, J., Adkins, J. F., Curry, W. B., Dokken, T., Hall, I. R.,
Herguera, J. C., Hirschi, J. J. M., Ivanova, E. V., Kissel, C., Marchal, O.,
Marchitto, T. M., McCave, I. N., McManus, J. F., Mulitza, S., Ninnemann, U.,
Peeters, F., Yu, E. F., and Zahn, R.: Atlantic meridional overturning
circulation during the last glacial maximum, Science, 316, 66–69,
https://doi.org/10.1126/science.1137127, 2007.
McCarthy, G. D., Smeed, D. A., Johns, W. E., Frajka-Williams, E., Moat, B.
I., Rayner, D., Baringer, M. O., Meinen, C. S., Collins, J., and Bryden, H.
L.: Measuring the Atlantic Meridional Overturning Circulation at
26∘N, Prog. Oceanogr., 130, 91–111,
https://doi.org/10.1016/j.pocean.2014.10.006, 2015.
McManus, J. F., Francois, R., Gherardl, J. M., Kelgwin, L., and
Drown-Leger, S.: Collapse and rapid resumption of Atlantic meridional
circulation linked to deglacial climate changes, Nature, 428,
834–837, https://doi.org/10.1038/nature02494, 2004.
Menviel, L., Yu, J., Joos, F., Mouchet, A., Meissner, K. J., and England,
M. H.: Poorly ventilated deep ocean at the Last Glacial Maximum inferred
from carbon isotopes: A data-model comparison study, Paleoceanography,
32, 2–17, https://doi.org/10.1002/2016PA003024, 2017.
Menviel, L. C., Spence, P., Skinner, L. C., Tachikawa, K., Friedrich, T.,
Missiaen, L., and Yu, J.: Enhanced mid-depth southward transport in the
Northeast Atlantic at the Last Glacial Maximum despite a weaker AMOC,
Paleoceanog. Paleoclimatol., 35, e2019PA003793,
https://doi.org/10.1029/2019PA003793, 2020.
Monnin, E., Indermühle, A., Dällenbach, A., Flückiger, J.,
Stauffer, B., Stocker, T. F., Raynaud, D., and Barnola, J. M.: Atmospheric
CO2 concentrations over the last glacial termination, Science,
291, 112–114, https://doi.org/10.1126/science.291.5501.112, 2001.
Muglia, J. and Schmittner, A.: Glacial Atlantic overturning increased by
wind stress in climate models, Geophys. Res. Lett., 42, 9862–9869,
https://doi.org/10.1002/2015GL064583, 2015.
Müller, S. A., Joos, F., Edwards, N. R., and Stocker, T. F.: Water mass
distribution and ventilation time scales in a cost-efficient, three
dimensional ocean model, J. Climate, 19, 5479–5499,
https://doi.org/10.1175/JCLI3911.1, 2006.
Oppo, D. W., Curry, W. B., and McManus, J. F.: What do benthic 13C and
18O data tell us about Atlantic circulation during Heinrich Stadial 1?,
Paleoceanography, 20, 353–368, https://doi.org/10.1002/2014PA002667, 2015.
Oppo, D. W., Gebbie, G., Huang, K. F., Curry, W. B., Marchitto, T. M., and
Pietro, K. R.: Data Constraints on Glacial Atlantic Water Mass Geometry and
Properties, Paleoceanog. Paleoclimatol., 33, 1013–1034,
https://doi.org/10.1029/2018PA003408, 2018.
Peltier, W. R.: Ice Age Paleotopography, Science, 265, 195–201,
https://doi.org/10.1126/science.265.5169.195, 1994.
Pico, T., Mitrovica, J. X., and Mix, A. C.: Sea level fingerprinting of the
Bering Strait flooding history detects the source of the Younger Dryas
climate event, Sci. Adv., 6, eaay2935, https://doi.org/10.1126/sciadv.aay2935,
2020.
Pöppelmeier, F., Blaser, P., Gutjahr, M., Jaccard, S., Frank, M., Max,
L., and Lippold, J.: Northern Sourced Water dominated the Atlantic Ocean
during the Last Glacial Maximum, Geology, 48, 826–829,
https://doi.org/10.1130/G47628.1, 2020.
Pöppelmeier, F., Scheen, J., Jeltsch-Thömmes, A., and Stocker, T. F.: Model output from the Bern3D model of pre-industrial and Last Glacial Maximum, Data set, Zenodo, https://doi.org/10.5281/zenodo.4436092, 2021.
Rahmstorf, S., Crucifix, M., Ganopolski, A., Goosse, H., Kamenkovich, I.,
Knutti, R., Lohmann, G., Marsh, R., Myzak, L. A., Wang, Z., and Weaver, A.
J.: Thermohaline circulation hysteresis: A model intercomparison, Geophys.
Res. Lett., 32, 1–5, https://doi.org/10.1029/2005GL023655, 2005.
Renssen, H., Mairesse, A., Goosse, H., Mathiot, P., Heiri, O., Roche, D. M.,
Nisancioglu, K. H., and Valdes, P. J.: Multiple causes of the Younger Dryas
cold period, Nat. Geosci., 8, 946–949,
https://doi.org/10.1038/ngeo2557, 2015.
Ritz, S. P., Stocker, T. F., and Joos, F.: A coupled dynamical ocean-energy
balance atmosphere model for paleoclimate studies, J. Climate, 24,
349–375, https://doi.org/10.1175/2010JCLI3351.1, 2011.
Roberts, W. H. G., Valdes, P. J., and Payne, A. J.: A new constraint on the
size of Heinrich Events from an iceberg/sediment model, Earth Planet. Sci.
Lett., 386, 1–9, https://doi.org/10.1016/j.epsl.2013.10.020, 2014.
Roth, R., Ritz, S. P., and Joos, F.: Burial-nutrient feedbacks amplify the sensitivity of atmospheric carbon dioxide to changes in organic matter remineralisation, Earth Syst. Dynam., 5, 321–343, https://doi.org/10.5194/esd-5-321-2014, 2014.
Sarnthein, M., Winn, K., Jung, S., Duplessy, J. C., Labeyrie, L.,
Erlenkeuser, H., and Ganssen, G.: Changes in east Atlantic deepwater
circulation over the last 30,000 years: Eight time slice reconstructions,
Paleoceanography, 9, 209–267, https://doi.org/10.1029/93PA03301, 1994.
Schmittner, A. and Egbert, G. D.: An improved parameterization of tidal mixing for ocean models, Geosci. Model Dev., 7, 211–224, https://doi.org/10.5194/gmd-7-211-2014, 2014.
Skinner, L. C., Primeau, F., Freeman, E., De La Fuente, M., Goodwin, P. A.,
Gottschalk, J., Huang, E., McCave, I. N., Noble, T. L., and Scrivner, A.
E.: Radiocarbon constraints on the glacial ocean circulation and its impact
on atmospheric CO2, Nat. Commun., 8, 1–10,
https://doi.org/10.1038/ncomms16010, 2017.
Stocker, T. F.: Past and future reorganizations in the climate system,
Quaternary Sci. Rev., 19, 301–319,
https://doi.org/10.1016/S0277-3791(99)00067-0, 2000.
Stocker, T. F. and Marchal, O.: Abrupt climate change in the computer: Is
it real?, P. Natl. Acad. Sci. USA, 97, 1362–1365,
https://doi.org/10.1073/pnas.97.4.1362, 2000.
Stocker, T. F. and Schmittner, A.: Influence of CO2 emission rates on
the stability of the thermohaline circulation, Nature, 388, 862–865,
https://doi.org/10.1038/42224, 1997.
Stocker, T. F. and Wright, D. G.: Rapid transitions of the ocean's deep
circulation induced by changes in surface water fluxes, Nature, 351,
729–732, https://doi.org/10.1038/351729a0, 1991.
Stocker, T. F., Timmermann, A., Renold, M., and Timm, O.: Effect of salt
compensation on the climate model response in simulations of large changes
of the Atlantic meridional overturning circulation, J. Climate,
20, 5912–5928, https://doi.org/10.1175/2007JCLI1662.1, 2007.
Stommel, H.: Thermohaline Convection with Two Stable Regimes, Tellus, 13, 224–230, https://doi.org/10.1111/j.2153-3490.1961.tb00079.x, 1961.
Wilmes, S. B., Schmittner, A., and Green, J. A. M.: Glacial Ice Sheet
Extent Effects on Modeled Tidal Mixing and the Global Overturning
Circulation, Paleoceanogr. Paleoclimatol., 34, 1437–1454,
https://doi.org/10.1029/2019PA003644, 2019.
Woodgate, R. A., Aagaard, K., and Weingartner, T. J.: Monthly temperature,
salinity, and transport variability of the Bering Strait through flow,
Geophys. Res. Lett., 32, 1–4, https://doi.org/10.1029/2004GL021880,
2005.
Zaucker, F., Stocker, T. F., and Broecker, W. S.: Atmospheric freshwater
fluxes and their effect on the global thermohaline circulation, J. Geophys.
Res., 99, 12443–12457, https://doi.org/10.1029/94JC00526, 1994.
Short summary
The stability of the Atlantic Meridional Overturning Circulation (AMOC) critically depends on its mean state. We simulate the response of the AMOC to North Atlantic freshwater perturbations under different glacial boundary conditions. We find that a closed Bering Strait greatly increases the AMOC's sensitivity to freshwater hosing. Further, the shift from mono- to bistability strongly depends on the chosen boundary conditions, with weaker circulation states exhibiting more abrupt transitions.
The stability of the Atlantic Meridional Overturning Circulation (AMOC) critically depends on...
