113 results on '"Baatsen, Michiel L. J."'
Search Results
2. Mid-Pliocene El Niño/Southern Oscillation suppressed by Pacific intertropical convergence zone shift
- Author
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Pontes, Gabriel M., Taschetto, Andréa S., Sen Gupta, Alex, Santoso, Agus, Wainer, Ilana, Haywood, Alan M., Chan, Wing-Le, Abe-Ouchi, Ayako, Stepanek, Christian, Lohmann, Gerrit, Hunter, Stephen J., Tindall, Julia C., Chandler, Mark A., Sohl, Linda E., Peltier, W. Richard, Chandan, Deepak, Kamae, Youichi, Nisancioglu, Kerim H., Zhang, Zhongshi, Contoux, Camille, Tan, Ning, Zhang, Qiong, Otto-Bliesner, Bette L., Brady, Esther C., Feng, Ran, von der Heydt, Anna S., Baatsen, Michiel L. J., and Oldeman, Arthur M.
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- 2022
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- View/download PDF
3. Response of Late-Eocene warmth to incipient glaciation on Antarctica
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Vermeulen, Dennis H.A., primary, Baatsen, Michiel L. J., additional, and von der Heydt, Anna S., additional
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- 2024
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- View/download PDF
4. Mid-Pliocene not analogous to high-CO2 climate when considering Northern Hemisphere winter variability
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Oldeman, Arthur Merlijn, primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, van Delden, Aarnout J., additional, and Dijkstra, Henk A., additional
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- 2024
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5. Suppression of mesoscale eddy mixing by topographic PV gradients
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Sterl, Miriam F., primary, LaCasce, Joseph H., additional, Groeskamp, Sjoerd, additional, Nummelin, Aleksi, additional, Isachsen, Pål E., additional, and Baatsen, Michiel L. J., additional
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- 2024
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6. Suppression of mesoscale eddy mixing by topographic PV gradients
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Sterl, Miriam Frauke, primary, Lacasce, Joseph H, additional, Groeskamp, Sjoerd, additional, Nummelin, Aleksi, additional, Isachsen, Pål E, additional, and Baatsen, Michiel L J, additional
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- 2024
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7. Mid-Pliocene not analogous to high-CO2 climate when considering Northern Hemisphere winter variability
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Marine and Atmospheric Research, Sub Physical Oceanography, Sub Dynamics Meteorology, Oldeman, Arthur Merlijn, Baatsen, Michiel L. J., Heydt, Anna S. von der, Delden, Aarnout J. van, Dijkstra, Henk A., Marine and Atmospheric Research, Sub Physical Oceanography, Sub Dynamics Meteorology, Oldeman, Arthur Merlijn, Baatsen, Michiel L. J., Heydt, Anna S. von der, Delden, Aarnout J. van, and Dijkstra, Henk A.
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- 2024
8. Similar North Pacific variability despite suppressed El Niño variability in the warm mid-Pliocene climate.
- Author
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Oldeman, Arthur Merlijn, Baatsen, Michiel L. J., von der Heydt, Anna S., Selten, Frank M., and Dijkstra, Henk A.
- Subjects
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ATMOSPHERIC carbon dioxide , *GLOBAL warming , *ATMOSPHERIC models ,EL Nino ,TROPICAL climate - Abstract
The mid-Pliocene is the most recent geological period with similar atmospheric CO2 concentration to the present day and similar surface temperatures to those projected at the end of this century for a moderate warming scenario. While not a perfect analogue, the mid-Pliocene can be used to study the functioning of the Earth system under similar forcings to a near future, especially regarding features in the climate system for which uncertainties exist in future projections. According to the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), the variability in the El Niño–Southern Oscillation (ENSO) was suppressed. In this study, we investigate how teleconnections of ENSO, specifically variability in the North Pacific atmosphere, respond to a suppressed ENSO according to PlioMIP2. The multi-model mean (MMM) shows a similar sea-level pressure (SLP) variability in the Aleutian Low (AL) in the mid-Pliocene and pre-industrial, but a per-model view reveals that the change in AL variability is related to the change in ENSO variability. Even though ENSO is suppressed, the teleconnection between ENSO sea-surface temperature (SST) anomalies, tropical precipitation, and North Pacific SLP anomalies is quite robust in the mid-Pliocene. We split AL variability in a part that is ENSO-related, and a residual variability which is related to internal stochastic variability, and find that the change in ENSO-related AL variability is strongly related to the change in ENSO variability itself, while the change in residual AL variability is unrelated to ENSO change. Since the internal atmospheric variability, which is the dominant forcing of the AL variability, is largely unchanged, we are able to understand that the AL variability is largely similar even though ENSO variability is suppressed. We find that the specific change in ENSO and AL variability depends on both the model equilibrium climate sensitivity and Earth system sensitivity. Finally, we present a perspective of (extra-)tropical Pacific variability in PlioMIP2, combining our results with literature findings on changes in the tropical mean climate and in the Pacific Decadal Oscillation (PDO). [ABSTRACT FROM AUTHOR]
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- 2024
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9. Response of Late-Eocene warmth to incipient glaciation on Antarctica.
- Author
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Vermeulen, Dennis H.A., Baatsen, Michiel L. J., and Heydt, Anna S. von der
- Abstract
The Eocene-Oligocene Transition (EOT) is marked by a sudden δ
18 O excursion occurring in two distinct phases, ~500 ky apart. These phases signal a shift from the warm Middle- to Late-Eocene greenhouse climate to cooler conditions, with global surface air temperatures decreasing by 3–5 °C and the emergence of the first continent-wide Antarctic Ice Sheet (AIS). While ice-sheet modelling suggests that ice sheet growth can be triggered by declining p CO2 , it still remains unclear how this transition has been initiated, in particular the first growth phase that seems to be related to oceanic and atmospheric cooling rather than ice sheet growth. Recent climate model simulations of the Late-Eocene show improved accuracy but depict climatic conditions that are not conducive to the survival of incipient ice sheets throughout the summer season. This study therefore examines whether it is plausible to develop ice sheets of sufficient scale to trigger the feedback mechanism(s) required to disrupt the atmospheric regime above the Antarctic continent during warm Late-Eocene summers and establish more favourable conditions for ice expansion. We thereby aim to assess the stability of an incipient AIS under varying radiative, orbital and cryospheric forcing. To do so, we evaluate Community Earth System Model 1.0.5 simulations, using a 38 Ma geo- and topographical reconstruction, considering different radiative (4 and 2 pre-industrial carbon) and orbital (present-day and low summer insolation) forcings. The climatic conditions prevailing during (the lead-up to) the EOT can be characterised as extremely seasonal and monsoonal, featuring a short yet intense summer period and contrasting cold winters — highly inhospitable to ice sheet growth for most of the continent, as limited snow accumulation is expected to survive the summer season. A narrow convergence zone with moist convection around the region where sub-cloud equivalent potential temperature is high is shown to exhibit a ring-like structure, advecting moist surface air advected from the Southern Ocean. This advection leads to high values of moist static energy and subsequent precipitation in these regions. To assess the influence of cryospheric forcing, we conducted another simulation, with regional, moderately-sized ice sheets imposed on the continent, to investigate their stability and influence on the atmospheric circulation. Regionally, these relatively small ice sheets respond strongly to radiative and orbital forcing, and demonstrate remarkably favourable self-sustaining and even expansion potential under 2 PIC and low summer insolation conditions. This emphasises a significant hysteresis effect for local and/or regional ice sheets on the Antarctic continent, suggesting the potential for a significant volume of ice on the Antarctic continent without an imminent full glaciation prior to the EOT. [ABSTRACT FROM AUTHOR]- Published
- 2024
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- View/download PDF
10. The hydrological cycle and ocean circulation of the Maritime Continent in the Pliocene: results from PlioMIP2
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Ren, Xin, primary, Lunt, Daniel J., additional, Hendy, Erica, additional, von der Heydt, Anna, additional, Abe-Ouchi, Ayako, additional, Otto-Bliesner, Bette, additional, Williams, Charles J. R., additional, Stepanek, Christian, additional, Guo, Chuncheng, additional, Chandan, Deepak, additional, Lohmann, Gerrit, additional, Tindall, Julia C., additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Kageyama, Masa, additional, Baatsen, Michiel L. J., additional, Tan, Ning, additional, Zhang, Qiong, additional, Feng, Ran, additional, Hunter, Stephen, additional, Chan, Wing-Le, additional, Peltier, W. Richard, additional, Li, Xiangyu, additional, Kamae, Youichi, additional, Zhang, Zhongshi, additional, and Haywood, Alan M., additional
- Published
- 2023
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11. On the quasi-steady vorticity balance in the mature stage of hurricane Irma (2017)
- Author
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Jong, Jasper, Baatsen, Michiel L. J., and Delden, Aarnout J.
- Abstract
Tropical cyclone (TC) intensification is a process depending on many factors related to the thermodynamical state and environmental influences. It remains a challenge to accurately model TC intensity due to the role of unsteady features like deep convective bursts, boundary layer dynamics and eddy processes. The impermeability theorem for potential vorticity substance, PVS, on isentropic surfaces provides a way to analyze the absolute vorticity structure and tendency in TCs. We will examine this theorem in a numerical simulation of hurricane Irma (2017) near lifetime-peak intensity. Hurricane Irma was a very intense hurricane that persisted as a category five hurricane on the Saffir-Simpson intensity scale for three consecutive days, the longest for any Atlantic hurricane since satellite observations. During this period the intensity of Irma was remarkably constant. According to the impermeability theorem, the radially outward vorticity flux due to divergence above the atmospheric boundary layer must be compensated by an equally strong radially inward vorticity flux due to the effect of diabatic heating in the presence of vertical wind shear. The model results agree with this theorem and we find a strong anticorrelation between the advective and diabatic components of the radial vorticity flux. The impact of parametrized turbulence on the vorticity balance is found to be weak and does not explain the residual flux that would otherwise close the vorticity balance.
- Published
- 2023
12. Past warm climate conditions show a shift in Northern Hemisphere winter variability towards a dominant North Pacific Oscillation
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Oldeman, Arthur Merlijn, primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, van Delden, Aarnout J., additional, and Dijkstra, Henk A., additional
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- 2023
- Full Text
- View/download PDF
13. Supplementary material to "Past warm climate conditions show a shift in Northern Hemisphere winter variability towards a dominant North Pacific Oscillation"
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Oldeman, Arthur Merlijn, primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, van Delden, Aarnout J., additional, and Dijkstra, Henk A., additional
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- 2023
- Full Text
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14. The Relationship Between the Global Mean Deep‐Sea and Surface Temperature During the Early Eocene
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Goudsmit‐Harzevoort, Barbara, primary, Lansu, Angelique, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, de Winter, Niels J., additional, Zhang, Yurui, additional, Abe‐Ouchi, Ayako, additional, de Boer, Agatha, additional, Chan, Wing‐Le, additional, Donnadieu, Yannick, additional, Hutchinson, David K., additional, Knorr, Gregor, additional, Ladant, Jean‐Baptiste, additional, Morozova, Polina, additional, Niezgodzki, Igor, additional, Steinig, Sebastian, additional, Tripati, Aradhna, additional, Zhang, Zhongshi, additional, Zhu, Jiang, additional, and Ziegler, Martin, additional
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- 2023
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15. Unraveling the mechanisms and implications of a stronger mid-Pliocene Atlantic Meridional Overturning Circulation (AMOC) in PlioMIP2
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Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, Weiffenbach, Julia E., Baatsen, Michiel L. J., Dijkstra, Henk A., Heydt, Anna S. von der, Abe-Ouchi, Ayako, Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Han, Zixuan, Haywood, Alan M., Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Tindall, Julia C., Williams, Charles J. R., Zhang, Qiong, Zhang, Zhongshi, Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, Weiffenbach, Julia E., Baatsen, Michiel L. J., Dijkstra, Henk A., Heydt, Anna S. von der, Abe-Ouchi, Ayako, Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Han, Zixuan, Haywood, Alan M., Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Tindall, Julia C., Williams, Charles J. R., Zhang, Qiong, and Zhang, Zhongshi
- Published
- 2023
16. Unraveling the mechanisms and implications of a stronger mid-Pliocene Atlantic Meridional Overturning Circulation (AMOC) in PlioMIP2
- Author
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Weiffenbach, Julia E., Baatsen, Michiel L. J., Dijkstra, Henk A., von der Heydt, Anna S., Abe-Ouchi, Ayako, Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Han, Zixuan, Haywood, Alan M., Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Tindall, Julia C., Williams, Charles J. R., Zhang, Qiong, Zhang, Zhongshi, Weiffenbach, Julia E., Baatsen, Michiel L. J., Dijkstra, Henk A., von der Heydt, Anna S., Abe-Ouchi, Ayako, Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Han, Zixuan, Haywood, Alan M., Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Tindall, Julia C., Williams, Charles J. R., Zhang, Qiong, and Zhang, Zhongshi
- Abstract
The mid-Pliocene warm period (3.264–3.025 Ma) is the most recent geological period in which the atmospheric CO2 concentration was approximately equal to the concentration we measure today (ca. 400 ppm). Sea surface temperature (SST) proxies indicate above-average warming over the North Atlantic in the mid-Pliocene with respect to the pre-industrial period, which may be linked to an intensified Atlantic Meridional Overturning Circulation (AMOC). Earlier results from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) show that the ensemble simulates a stronger AMOC in the mid-Pliocene than in the pre-industrial. However, no consistent relationship between the stronger mid-Pliocene AMOC and either the Atlantic northward ocean heat transport (OHT) or average North Atlantic SSTs has been found. In this study, we look further into the drivers and consequences of a stronger AMOC in mid-Pliocene compared to pre-industrial simulations in PlioMIP2. We find that all model simulations with a closed Bering Strait and Canadian Archipelago show reduced freshwater transport from the Arctic Ocean into the North Atlantic. This contributes to an increase in salinity in the subpolar North Atlantic and Labrador Sea that can be linked to the stronger AMOC in the mid-Pliocene. To investigate the dynamics behind the ensemble's variable response of the total Atlantic OHT to the stronger AMOC, we separate the Atlantic OHT into two components associated with either the overturning circulation or the wind-driven gyre circulation. While the ensemble mean of the overturning component is increased significantly in magnitude in the mid-Pliocene, it is partly compensated by a reduction in the gyre component in the northern subtropical gyre region. This indicates that the lack of relationship between the total OHT and AMOC is due to changes in OHT by the subtropical gyre. The overturning and gyre components should therefore be considered separately to gain a more complete understanding of
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- 2023
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17. The Relationship Between the Global Mean Deep-Sea and Surface Temperature During the Early Eocene
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Goudsmit-Harzevoort, Barbara, Lansu, Angelique, Baatsen, Michiel L. J., von der Heydt, Anna S., de Winter, Niels J., Zhang, Yurui, Abe-Ouchi, Ayako, de Boer, Agatha M., Chan, Wing-Le, Donnadieu, Yannick, Hutchinson, David K., Knorr, Gregor, Ladant, Jean-Baptiste, Morozova, Polina, Niezgodzki, Igor, Steinig, Sebastian, Tripati, Aradhna, Zhang, Zhongshi, Zhu, Jiang, Ziegler, Martin, Goudsmit-Harzevoort, Barbara, Lansu, Angelique, Baatsen, Michiel L. J., von der Heydt, Anna S., de Winter, Niels J., Zhang, Yurui, Abe-Ouchi, Ayako, de Boer, Agatha M., Chan, Wing-Le, Donnadieu, Yannick, Hutchinson, David K., Knorr, Gregor, Ladant, Jean-Baptiste, Morozova, Polina, Niezgodzki, Igor, Steinig, Sebastian, Tripati, Aradhna, Zhang, Zhongshi, Zhu, Jiang, and Ziegler, Martin
- Abstract
Estimates of global mean near-surface air temperature (global SAT) for the Cenozoic era rely largely on paleo-proxy data of deep-sea temperature (DST), with the assumption that changes in global SAT covary with changes in the global mean deep-sea temperature (global DST) and global mean sea-surface temperature (global SST). We tested the validity of this assumption by analyzing the relationship between global SST, SAT, and DST using 25 different model simulations from the Deep-Time Model Intercomparison Project simulating the early Eocene Climatic Optimum (EECO) with varying CO2 levels. Similar to the modern situation, we find limited spatial variability in DST, indicating that local DST estimates can be regarded as a first order representative of global DST. In line with previously assumed relationships, linear regression analysis indicates that both global DST and SAT respond stronger to changes in atmospheric CO2 than global SST by a similar factor. Consequently, this model-based analysis validates the assumption that changes in global DST can be used to estimate changes in global SAT during the early Cenozoic. Paleo-proxy estimates of global DST, SST, and SAT during EECO show the best fit with model simulations with a 1,680 ppm atmospheric CO2 level. This matches paleo-proxies of EECO atmospheric CO2, indicating a good fit between models and proxy-data.
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- 2023
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18. The hydrological cycle and ocean circulation of the Maritime Continent in the Pliocene: results from PlioMIP2
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Ren, Xin, Lunt, Daniel J., Hendy, Erica, von der Heydt, Anna, Abe-Ouchi, Ayako, Otto-Bliesner, Bette, Williams, Charles J. R., Stepanek, Christian, Guo, Chuncheng, Chandan, Deepak, Lohmann, Gerrit, Tindall, Julia C., Sohl, Linda E., Chandler, Mark A., Kageyama, Masa, Baatsen, Michiel L. J., Tan, Ning, Zhang, Qiong, Feng, Ran, Hunter, Stephen, Chan, Wing-Le, Peltier, W. Richard, Li, Xiangyu, Kamae, Youichi, Zhang, Zhongshi, Haywood, Alan M., Ren, Xin, Lunt, Daniel J., Hendy, Erica, von der Heydt, Anna, Abe-Ouchi, Ayako, Otto-Bliesner, Bette, Williams, Charles J. R., Stepanek, Christian, Guo, Chuncheng, Chandan, Deepak, Lohmann, Gerrit, Tindall, Julia C., Sohl, Linda E., Chandler, Mark A., Kageyama, Masa, Baatsen, Michiel L. J., Tan, Ning, Zhang, Qiong, Feng, Ran, Hunter, Stephen, Chan, Wing-Le, Peltier, W. Richard, Li, Xiangyu, Kamae, Youichi, Zhang, Zhongshi, and Haywood, Alan M.
- Abstract
The Maritime Continent (MC) forms the western boundary of the tropical Pacific Ocean, and relatively small changes in this region can impact the climate locally and remotely. In the mid-Piacenzian warm period of the Pliocene (mPWP; 3.264 to 3.025 Ma) atmospheric CO2 concentrations were ∼ 400 ppm, and the subaerial Sunda and Sahul shelves made the land–sea distribution of the MC different to today. Topographic changes and elevated levels of CO2, combined with other forcings, are therefore expected to have driven a substantial climate signal in the MC region at this time. By using the results from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), we study the mean climatic features of the MC in the mPWP and changes in Indonesian Throughflow (ITF) with respect to the preindustrial. Results show a warmer and wetter mPWP climate of the MC and lower sea surface salinity in the surrounding ocean compared with the preindustrial. Furthermore, we quantify the volume transfer through the ITF; although the ITF may be expected to be hindered by the subaerial shelves, 10 out of 15 models show an increased volume transport compared with the preindustrial. In order to avoid undue influence from closely related models that are present in the PlioMIP2 ensemble, we introduce a new metric, the multi-cluster mean (MCM), which is based on cluster analysis of the individual models. We study the effect that the choice of MCM versus the more traditional analysis of multi-model mean (MMM) and individual models has on the discrepancy between model results and data. We find that models, which reproduce modern MC climate well, are not always good at simulating the mPWP climate anomaly of the MC. By comparing with individual models, the MMM and MCM reproduce the preindustrial sea surface temperature (SST) of the reanalysis better than most individual models and produce less discrepancy with reconstructed sea surface temperature anomalies (SSTA) than most individual models in the MC.
- Published
- 2023
- Full Text
- View/download PDF
19. Unraveling the mechanisms and implications of a stronger mid-Pliocene Atlantic Meridional Overturning Circulation (AMOC) in PlioMIP2
- Author
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Weiffenbach, Julia E., primary, Baatsen, Michiel L. J., additional, Dijkstra, Henk A., additional, von der Heydt, Anna S., additional, Abe-Ouchi, Ayako, additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Han, Zixuan, additional, Haywood, Alan M., additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Tindall, Julia C., additional, Williams, Charles J. R., additional, Zhang, Qiong, additional, and Zhang, Zhongshi, additional
- Published
- 2023
- Full Text
- View/download PDF
20. Supplementary material to "The hydrological cycle and ocean circulation of the Maritime Continent in the mid-Pliocene: results from PlioMIP2"
- Author
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Ren, Xin, primary, Lunt, Daniel J., additional, Hendy, Erica, additional, von der Heydt, Anna, additional, Abe-Ouchi, Ayako, additional, Otto-Bliesner, Bette L., additional, Williams, Charles J. R., additional, Stepanek, Christian, additional, Guo, Chuncheng, additional, Chandan, Deepak, additional, Lohmann, Gerrit, additional, Tindall, Julia C., additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Kageyama, Masa, additional, Baatsen, Michiel L. J., additional, Tan, Ning, additional, Zhang, Qiong, additional, Feng, Ran, additional, Chan, Wing-Le, additional, Peltier, W. Richard, additional, Li, Xiangyu, additional, Kamae, Youichi, additional, Zhang, Zhongshi, additional, and Haywood, Alan M., additional
- Published
- 2022
- Full Text
- View/download PDF
21. The hydrological cycle and ocean circulation of the Maritime Continent in the mid-Pliocene: results from PlioMIP2
- Author
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Ren, Xin, primary, Lunt, Daniel J., additional, Hendy, Erica, additional, von der Heydt, Anna, additional, Abe-Ouchi, Ayako, additional, Otto-Bliesner, Bette L., additional, Williams, Charles J. R., additional, Stepanek, Christian, additional, Guo, Chuncheng, additional, Chandan, Deepak, additional, Lohmann, Gerrit, additional, Tindall, Julia C., additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Kageyama, Masa, additional, Baatsen, Michiel L. J., additional, Tan, Ning, additional, Zhang, Qiong, additional, Feng, Ran, additional, Chan, Wing-Le, additional, Peltier, W. Richard, additional, Li, Xiangyu, additional, Kamae, Youichi, additional, Zhang, Zhongshi, additional, and Haywood, Alan M., additional
- Published
- 2022
- Full Text
- View/download PDF
22. On the quasi-steady vorticity balance in the mature stage of hurricane Irma (2017).
- Author
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Jong, Jasper de, Baatsen, Michiel L. J., and Delden, Aarnout J. van
- Subjects
TROPICAL cyclones ,HURRICANE Irma, 2017 ,ATMOSPHERIC boundary layer ,VORTEX motion ,VERTICAL wind shear ,BOUNDARY layer (Aerodynamics) ,ADVECTION-diffusion equations - Abstract
Tropical cyclone (TC) intensification is a process depending on many factors related to the thermodynamical state and environmental influences. It remains a challenge to accurately model TC intensity due to the role of unsteady features like deep convective bursts, boundary layer dynamics and eddy processes. The impermeability theorem for potential vorticity substance, PVS , on isentropic surfaces provides a way to analyze the absolute vorticity structure and tendency in TC s. We will examine this theorem in a numerical simulation of hurricane Irma (2017) near lifetime-peak intensity. Hurricane Irma was a very intense hurricane that persisted as a category five hurricane on the Saffir-Simpson intensity scale for three consecutive days, the longest for any Atlantic hurricane since satellite observations. During this period the intensity of Irma was remarkably constant. According to the impermeability theorem, the radially outward vorticity flux due to divergence above the atmospheric boundary layer must be compensated by an equally strong radially inward vorticity flux due to the effect of diabatic heating in the presence of vertical wind shear. The model results agree with this theorem and we find a strong anticorrelation between the advective and diabatic components of the radial vorticity flux. The impact of parametrized turbulence on the vorticity balance is found to be weak and does not explain the residual flux that would otherwise close the vorticity balance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. Supplementary material to "Unraveling the mechanisms and implications of a stronger mid-Pliocene AMOC in PlioMIP2"
- Author
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Weiffenbach, Julia E., primary, Baatsen, Michiel L. J., additional, Dijkstra, Henk A., additional, von der Heydt, Anna S., additional, Abe-Ouchi, Ayako, additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Han, Zixuan, additional, Haywood, Alan M., additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Tindall, Julia C., additional, Williams, Charles J. R., additional, Zhang, Qiong, additional, and Zhang, Zhongshi, additional
- Published
- 2022
- Full Text
- View/download PDF
24. Unraveling the mechanisms and implications of a stronger mid-Pliocene AMOC in PlioMIP2
- Author
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Weiffenbach, Julia E., primary, Baatsen, Michiel L. J., additional, Dijkstra, Henk A., additional, von der Heydt, Anna S., additional, Abe-Ouchi, Ayako, additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Han, Zixuan, additional, Haywood, Alan M., additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Tindall, Julia C., additional, Williams, Charles J. R., additional, Zhang, Qiong, additional, and Zhang, Zhongshi, additional
- Published
- 2022
- Full Text
- View/download PDF
25. Mid-Pliocene El Niño/Southern Oscillation suppressed by Pacific intertropical convergence zone shift
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Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, Pontes, Gabriel M., Taschetto, Andrea S., Sen Gupta, Alex, Santoso, Agus, Wainer, Ilana, Haywood, Alan M., Chan, Wing-Le, Abe-Ouchi, Ayako, Stepanek, Christian, Lohmann, Gerrit, Hunter, Stephen J., Tindall, Julia C., Chandler, Mark A., Sohl, Linda E., Peltier, W. Richard, Chandan, Deepak, Kamae, Youichi, Nisancioglu, Kerim H., Zhang, Zhongshi, Contoux, Camille, Tan, Ning, Zhang, Qiong, Otto-Bliesner, Bette L., Brady, Esther C., Feng, Ran, von der Heydt, Anna S., Baatsen, Michiel L. J., Oldeman, Arthur M., Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, Pontes, Gabriel M., Taschetto, Andrea S., Sen Gupta, Alex, Santoso, Agus, Wainer, Ilana, Haywood, Alan M., Chan, Wing-Le, Abe-Ouchi, Ayako, Stepanek, Christian, Lohmann, Gerrit, Hunter, Stephen J., Tindall, Julia C., Chandler, Mark A., Sohl, Linda E., Peltier, W. Richard, Chandan, Deepak, Kamae, Youichi, Nisancioglu, Kerim H., Zhang, Zhongshi, Contoux, Camille, Tan, Ning, Zhang, Qiong, Otto-Bliesner, Bette L., Brady, Esther C., Feng, Ran, von der Heydt, Anna S., Baatsen, Michiel L. J., and Oldeman, Arthur M.
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- 2022
26. Past warm climate conditions show a shift in Northern Hemisphere winter variability towards a dominant North Pacific Oscillation.
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Oldeman, Arthur Merlijn, Baatsen, Michiel L. J., Heydt, Anna S. von der, Delden, Aarnout J. van, and Dijkstra, Henk A.
- Subjects
GLOBAL warming ,CLIMATE change models ,ATMOSPHERIC circulation ,WINTER ,GREENLAND ice ,JET streams - Abstract
In this study, we address the question whether the mid-Pliocene climate can act as an analog for a future warm climate with elevated CO
2 concentrations, specifically regarding Northern Hemisphere winter variability. We use a set of sensitivity experiments with the global coupled climate model CESM1.0.5, that is a part of PlioMIP2, to separate the response to a CO2 doubling and to mid-Pliocene boundary conditions other than CO2 . In the CO2 doubling experiment, the Aleutian low deepens, and the Pacific-North American pattern (PNA) strengthens. In response to the mid-Pliocene boundary conditions, sea-level pressure variance decreases over the North Pacific, the PNA becomes weaker, and the North Pacific Oscillation (NPO) becomes the dominant mode of variability. The mid-Pliocene simulation shows a weak North Pacific jet stream that is less variable in intensity, but has a high level of variation in jet latitude, consistent with a dominant NPO, and indicating that North Pacific atmospheric dynamics become more North Atlantic-like. We show that the weakening of the Aleutian low, and subsequent relative dominance of the NPO over the PNA, is related to the mean surface temperature field in the mid-Pliocene. Variability in the North Atlantic shows little variation between all simulations. The differences between the mid-Pliocene and pre-industrial surface temperature fields are likely caused by differences in orography, which includes the closure of Arctic gateways, rather than a reduced Greenland Ice Sheet. The opposite response in North Pacific winter variability to elevated CO2 or mid-Pliocene boundary conditions demonstrate that the mid-Pliocene climate cannot serve as a future analog in this regard. [ABSTRACT FROM AUTHOR]- Published
- 2023
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- View/download PDF
27. Warm mid-Pliocene conditions without high climate sensitivity: the CCSM4-Utrecht (CESM 1.0.5) contribution to the PlioMIP2
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Baatsen, Michiel L. J., primary, von der Heydt, Anna S., additional, Kliphuis, Michael A., additional, Oldeman, Arthur M., additional, and Weiffenbach, Julia E., additional
- Published
- 2022
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28. The DeepMIP Contribution to PMIP4: Experimental Design for Model Simulations of the EECO, PETM, and pre-PETM (version 1.0)
- Author
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Lunt, Daniel J, Huber, Matthew, Anagnostou, Eleni, Baatsen, Michiel L. J, Caballero, Rodrigo, DeConto, Rob, Dijkstra, Henk A, Donnadieu, Yannick, Evans, David, Feng, Ran, and LeGrande, Allegra N
- Subjects
Meteorology And Climatology - Abstract
Past warm periods provide an opportunity to evaluate climate models under extreme forcing scenarios, in particular high ( greater than 800 ppmv) atmospheric CO2 concentrations. Although a post hoc intercomparison of Eocene (approximately 50 Ma) climate model simulations and geological data has been carried out previously, models of past high-CO2 periods have never been evaluated in a consistent framework. Here, we present an experimental design for climate model simulations of three warm periods within the early Eocene and the latest Paleocene (the EECO, PETM, and pre-PETM). Together with the CMIP6 pre-industrial control and abrupt 4(times) CO2 simulations, and additional sensitivity studies, these form the first phase of DeepMIP - the Deep-time Model Intercomparison Project, itself a group within the wider Paleoclimate Modeling Intercomparison Project (PMIP). The experimental design specifies and provides guidance on boundary conditions associated with palaeogeography, greenhouse gases, astronomical configuration, solar constant, land surface processes, and aerosols. Initial conditions, simulation length, and output variables are also specified. Finally, we explain how the geological data sets, which will be used to evaluate the simulations, will be developed.
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- 2017
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29. Evaluating the large-scale hydrological cycle response within the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) ensemble
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Han, Zixuan, primary, Zhang, Qiong, additional, Li, Qiang, additional, Feng, Ran, additional, Haywood, Alan M., additional, Tindall, Julia C., additional, Hunter, Stephen J., additional, Otto-Bliesner, Bette L., additional, Brady, Esther C., additional, Rosenbloom, Nan, additional, Zhang, Zhongshi, additional, Li, Xiangyu, additional, Guo, Chuncheng, additional, Nisancioglu, Kerim H., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Tan, Ning, additional, Ramstein, Gilles, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Williams, Charles J. R., additional, Lunt, Daniel J., additional, Cheng, Jianbo, additional, Wen, Qin, additional, and Burls, Natalie J., additional
- Published
- 2021
- Full Text
- View/download PDF
30. Reduced El Niño variability in the mid-Pliocene according to the PlioMIP2 ensemble
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Oldeman, Arthur M., primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Dijkstra, Henk A., additional, Tindall, Julia C., additional, Abe-Ouchi, Ayako, additional, Booth, Alice R., additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Haywood, Alan M., additional, Hunter, Stephen J., additional, Kamae, Youichi, additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Pontes, Gabriel M., additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Zhang, Qiong, additional, Zhang, Zhongshi, additional, Wainer, Ilana, additional, and Williams, Charles J. R., additional
- Published
- 2021
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31. The hydrological cycle and ocean circulation of the Maritime Continent in the mid-Pliocene: results from PlioMIP2.
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Ren, Xin, Lunt, Daniel J., Hendy, Erica, von der Heydt, Anna, Abe-Ouchi, Ayako, Otto-Bliesner, Bette L., Williams, Charles J. R., Stepanek, Christian, Guo, Chuncheng, Chandan, Deepak, Lohmann, Gerrit, Tindall, Julia C., Sohl, Linda E., Chandler, Mark A., Kageyama, Masa, Baatsen, Michiel L. J., Tan, Ning, Zhang, Qiong, Feng, Ran, and Chan, Wing-Le
- Subjects
HYDROLOGIC cycle ,OCEAN temperature ,SALINITY ,CLUSTER analysis (Statistics) - Abstract
The Maritime Continent (MC) forms the western boundary of the tropical Pacific Ocean, and relatively small changes in this region can impact the climate locally and remotely. In the mid-Pliocene (from 3.264 to 3.025 million years before present), atmospheric CO
2 concentrations were ~ 400 ppm, and the subaerial Sunda and Sahul shelves made the land-sea distribution of the MC different to today. Topographic changes and elevated levels of CO2 , combined with other forcings, are therefore expected to have driven a substantial climate signal in the MC region at this time. By using the results from the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) we study the mean climatic features of the MC in the mid-Pliocene and changes in Indonesian Throughflow (ITF) with respect to preindustrial. Results show a warmer and wetter mid-Pliocene climate of the MC and lower sea surface salinity in the surrounding ocean compared with preindustrial. Furthermore, we quantify the volume transfer through the ITF; although the ITF may be expected to be hindered by the subaerial shelves, 10 out of 15 models show an increased volume transport compared with preindustrial. In order to avoid undue influence from closely-related models that are present in the PlioMIP2 ensemble, we introduce a new metric – the multi-cluster mean (MCM), based on cluster analysis of the individual models. We study the effect that the choice of MCM versus the more traditional analysis of multi-model mean (MMM) and individual models has on the discrepancy between model results and reconstructed proxy data. The clusters reveal spatial signals that are not captured by the MMM, so that the MCM provides us with a new way to explore the results from model ensemble that include similar models. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
32. The hydrological cycle and ocean circulation of the Maritime Continent in the mid-Pliocene: results from PlioMIP2.
- Author
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Xin Ren, Lunt, Daniel J., Hendy, Erica, von der Heydt, Anna, Abe-Ouchi, Ayako, Otto-Bliesner, Bette, Williams, Charles J. R., Stepanek, Christian, Chuncheng Guo, Chandan, Deepak, Lohmann, Gerrit, Tindall, Julia C., Sohl, Linda E., Chandler, Mark A., Kageyama, Masa, Baatsen, Michiel L. J., Ning Tan, Qiong Zhang, Ran Feng, and Wing-Le Chan
- Abstract
The Maritime Continent (MC) forms the western boundary of the tropical Pacific Ocean, and relatively small changes in this region can impact the climate locally and remotely. In the mid-Pliocene (from 3.264 to 3.025 million years before present), atmospheric CO
2 concentrations were ~ 400 ppm, and the subaerial Sunda and Sahul shelves made the land-sea distribution of the MC different to today. Topographic changes and elevated levels of CO2 , combined with other forcings, are therefore expected to have driven a substantial climate signal in the MC region at this time. By using the results from the Pliocene Model Intercomparison Project phase 2 (PlioMIP2) we study the mean climatic features of the MC in the mid-Pliocene and changes in Indonesian Throughflow (ITF) with respect to preindustrial. Results show a warmer and wetter mid-Pliocene climate of the MC and lower sea surface salinity in the surrounding ocean compared with preindustrial. Furthermore, quantify the volume transfer through the ITF; although the ITF may be expected to be hindered by the subaerial shelves, out of 15 models show an increased volume transport compared with preindustrial. In order to avoid undue influence from closely-related models that are present in the PlioMIP2 ensemble, we introduce a new metric - the multi-cluster mean (MCM), based on cluster analysis of the individual models. We study the effect that the choice of MCM versus the more traditional analysis of multi-model mean (MMM) and individual models has on the discrepancy between model results and reconstructed proxy data. The clusters reveal spatial signals that are not captured by the MMM, that the MCM provides us with a new way to explore the results from model ensemble that include similar models. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
33. Warm mid-Pliocene conditions without high climate sensitivity: the CCSM4-Utrecht (CESM 1.0.5) contribution to the PlioMIP2
- Author
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Baatsen, Michiel L. J., primary, von der Heydt, Anna S., additional, Kliphuis, Michael A., additional, Oldeman, Arthur M., additional, and Weiffenbach, Julia E., additional
- Published
- 2021
- Full Text
- View/download PDF
34. Mid-Pliocene West African Monsoon rainfall as simulated in the PlioMIP2 ensemble
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Berntell, Ellen, primary, Zhang, Qiong, additional, Li, Qiang, additional, Haywood, Alan M., additional, Tindall, Julia C., additional, Hunter, Stephen J., additional, Zhang, Zhongshi, additional, Li, Xiangyu, additional, Guo, Chuncheng, additional, Nisancioglu, Kerim H., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Tan, Ning, additional, Contoux, Camille, additional, Ramstein, Gilles, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Chandan, Deepak, additional, Peltier, William Richard, additional, Abe-Ouchi, Ayako, additional, Chan, Wing-Le, additional, Kamae, Youichi, additional, Williams, Charles J. R., additional, Lunt, Daniel J., additional, Feng, Ran, additional, Otto-Bliesner, Bette L., additional, and Brady, Esther C., additional
- Published
- 2021
- Full Text
- View/download PDF
35. Evaluating the large-scale hydrological cycle response within the PlioMIP2 ensemble
- Author
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Han, Zixuan, primary, Zhang, Qiong, additional, Li, Qiang, additional, Feng, Ran, additional, Haywood, Alan M., additional, Tindall, Julia C., additional, Hunter, Stephen J., additional, Otto-Bliesner, Bette L., additional, Brady, Esther C., additional, Rosenbloom, Nan, additional, Zhang, Zhongshi, additional, Li, Xiangyu, additional, Guo, Chuncheng, additional, Nisancioglu, Kerim H., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Tan, Ning, additional, Ramstein, Gilles, additional, Baatsen, Michiel L. J., additional, Heydt, Anna S. von der, additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Williams, Charles J. R., additional, Lunt, Daniel J., additional, Cheng, Jianbo, additional, Wen, Qin, additional, and Burls, Natalie J., additional
- Published
- 2021
- Full Text
- View/download PDF
36. Supplementary material to "Reduced El Niño variability in the mid-Pliocene according to the PlioMIP2 ensemble"
- Author
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Oldeman, Arthur Merlijn, primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Dijkstra, Henk A., additional, Tindall, Julia C., additional, Abe-Ouchi, Ayako, additional, Booth, Alice R., additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Haywood, Alan M., additional, Hunter, Stephen J., additional, Kamae, Youichi, additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Pontes, Gabriel M., additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Zhang, Qiong, additional, Zhang, Zhongshi, additional, Wainer, Ilana, additional, and Williams, Charles J. R., additional
- Published
- 2021
- Full Text
- View/download PDF
37. Reduced El Niño variability in the mid-Pliocene according to the PlioMIP2 ensemble
- Author
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Oldeman, Arthur Merlijn, primary, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Dijkstra, Henk A., additional, Tindall, Julia C., additional, Abe-Ouchi, Ayako, additional, Booth, Alice R., additional, Brady, Esther C., additional, Chan, Wing-Le, additional, Chandan, Deepak, additional, Chandler, Mark A., additional, Contoux, Camille, additional, Feng, Ran, additional, Guo, Chuncheng, additional, Haywood, Alan M., additional, Hunter, Stephen J., additional, Kamae, Youichi, additional, Li, Qiang, additional, Li, Xiangyu, additional, Lohmann, Gerrit, additional, Lunt, Daniel J., additional, Nisancioglu, Kerim H., additional, Otto-Bliesner, Bette L., additional, Peltier, W. Richard, additional, Pontes, Gabriel M., additional, Ramstein, Gilles, additional, Sohl, Linda E., additional, Stepanek, Christian, additional, Tan, Ning, additional, Zhang, Qiong, additional, Zhang, Zhongshi, additional, Wainer, Ilana, additional, and Williams, Charles J. R., additional
- Published
- 2021
- Full Text
- View/download PDF
38. Reduced El Niño variability in the mid-Pliocene according to the PlioMIP2 ensemble
- Author
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Oldeman, Arthur M., Baatsen, Michiel L. J., von der Heydt, Anna S., Dijkstra, Henk A., Tindall, Julia C., Abe-Ouchi, Ayako, Booth, Alice R., Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Haywood, Alan M., Hunter, Stephen J., Kamae, Youichi, Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Pontes, Gabriel M., Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Zhang, Qiong, Zhang, Zhongshi, Wainer, Ilana, Williams, Charles J. R., Oldeman, Arthur M., Baatsen, Michiel L. J., von der Heydt, Anna S., Dijkstra, Henk A., Tindall, Julia C., Abe-Ouchi, Ayako, Booth, Alice R., Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Feng, Ran, Guo, Chuncheng, Haywood, Alan M., Hunter, Stephen J., Kamae, Youichi, Li, Qiang, Li, Xiangyu, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Pontes, Gabriel M., Ramstein, Gilles, Sohl, Linda E., Stepanek, Christian, Tan, Ning, Zhang, Qiong, Zhang, Zhongshi, Wainer, Ilana, and Williams, Charles J. R.
- Abstract
The mid-Pliocene warm period (3.264–3.025 Ma) is the most recent geological period during which atmospheric CO2 levels were similar to recent historical values (∼400 ppm). Several proxy reconstructions for the mid-Pliocene show highly reduced zonal sea surface temperature (SST) gradients in the tropical Pacific Ocean, indicating an El Niño-like mean state. However, past modelling studies do not show these highly reduced gradients. Efforts to understand mid-Pliocene climate dynamics have led to the Pliocene Model Intercomparison Project (PlioMIP). Results from the first phase (PlioMIP1) showed clear El Niño variability (albeit significantly reduced) and did not show the greatly reduced time-mean zonal SST gradient suggested by some of the proxies. In this work, we study El Niño–Southern Oscillation (ENSO) variability in the PlioMIP2 ensemble, which consists of additional global coupled climate models and updated boundary conditions compared to PlioMIP1. We quantify ENSO amplitude, period, spatial structure and “flavour”, as well as the tropical Pacific annual mean state in mid-Pliocene and pre-industrial simulations. Results show a reduced ENSO amplitude in the model-ensemble mean (−24 %) with respect to the pre-industrial, with 15 out of 17 individual models showing such a reduction. Furthermore, the spectral power of this variability considerably decreases in the 3–4-year band. The spatial structure of the dominant empirical orthogonal function shows no particular change in the patterns of tropical Pacific variability in the model-ensemble mean, compared to the pre-industrial. Although the time-mean zonal SST gradient in the equatorial Pacific decreases for 14 out of 17 models (0.2 ∘C reduction in the ensemble mean), there does not seem to be a correlation with the decrease in ENSO amplitude. The models showing the most “El Niño-like” mean state changes show a similar ENSO amplitude to that in the pre-industrial reference, while models showing more “La Niña-like” m
- Published
- 2021
39. Evaluating the large-scale hydrological cycle response within the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) ensemble
- Author
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Han, Zixuan, Zhang, Qiong, Li, Qiang, Feng, Ran, Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Otto-Bliesner, Bette L., Brady, Esther C., Rosenbloom, Nan, Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Nisancioglu, Kerim H., Stepanek, Christian, Lohmann, Gerrit, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Ramstein, Gilles, Baatsen, Michiel L. J., von der Heydt, Anna S., Chandan, Deepak, Peltier, W. Richard, Williams, Charles J. R., Lunt, Daniel J., Cheng, Jianbo, Wen, Qin, Burls, Natalie J., Han, Zixuan, Zhang, Qiong, Li, Qiang, Feng, Ran, Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Otto-Bliesner, Bette L., Brady, Esther C., Rosenbloom, Nan, Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Nisancioglu, Kerim H., Stepanek, Christian, Lohmann, Gerrit, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Ramstein, Gilles, Baatsen, Michiel L. J., von der Heydt, Anna S., Chandan, Deepak, Peltier, W. Richard, Williams, Charles J. R., Lunt, Daniel J., Cheng, Jianbo, Wen, Qin, and Burls, Natalie J.
- Abstract
The mid-Pliocene (∼3 Ma) is one of the most recent warm periods with high CO2 concentrations in the atmosphere and resulting high temperatures, and it is often cited as an analog for near-term future climate change. Here, we apply a moisture budget analysis to investigate the response of the large-scale hydrological cycle at low latitudes within a 13-model ensemble from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The results show that increased atmospheric moisture content within the mid-Pliocene ensemble (due to the thermodynamic effect) results in wetter conditions over the deep tropics, i.e., the Pacific intertropical convergence zone (ITCZ) and the Maritime Continent, and drier conditions over the subtropics. Note that the dynamic effect plays a more important role than the thermodynamic effect in regional precipitation minus evaporation (PmE) changes (i.e., northward ITCZ shift and wetter northern Indian Ocean). The thermodynamic effect is offset to some extent by a dynamic effect involving a northward shift of the Hadley circulation that dries the deep tropics and moistens the subtropics in the Northern Hemisphere (i.e., the subtropical Pacific). From the perspective of Earth's energy budget, the enhanced southward cross-equatorial atmospheric transport (0.22 PW), induced by the hemispheric asymmetries of the atmospheric energy, favors an approximately 1∘ northward shift of the ITCZ. The shift of the ITCZ reorganizes atmospheric circulation, favoring a northward shift of the Hadley circulation. In addition, the Walker circulation consistently shifts westward within PlioMIP2 models, leading to wetter conditions over the northern Indian Ocean. The PlioMIP2 ensemble highlights that an imbalance of interhemispheric atmospheric energy during the mid-Pliocene could have led to changes in the dynamic effect, offsetting the thermodynamic effect and, hence, altering mid-Pliocene hydroclimate.
- Published
- 2021
40. Mid-Pliocene West African Monsoon rainfall as simulated in the PlioMIP2 ensemble
- Author
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Berntell, Ellen, Zhang, Qiong, Li, Qiang, Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Nisancioglu, Kerim H., Stepanek, Christian, Lohmann, Gerrit, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Baatsen, Michiel L. J., von der Heydt, Anna S., Chandan, Deepak, Peltier, William Richard, Abe-Ouchi, Ayako, Chan, Wing-Le, Kamae, Youichi, Williams, Charles J. R., Lunt, Daniel J., Feng, Ran, Otto-Bliesner, Bette L., Brady, Esther C., Berntell, Ellen, Zhang, Qiong, Li, Qiang, Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Nisancioglu, Kerim H., Stepanek, Christian, Lohmann, Gerrit, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Baatsen, Michiel L. J., von der Heydt, Anna S., Chandan, Deepak, Peltier, William Richard, Abe-Ouchi, Ayako, Chan, Wing-Le, Kamae, Youichi, Williams, Charles J. R., Lunt, Daniel J., Feng, Ran, Otto-Bliesner, Bette L., and Brady, Esther C.
- Abstract
The mid-Pliocene warm period (mPWP; ∼3.2 million years ago) is seen as the most recent time period characterized by a warm climate state, with similar to modern geography and ∼400 ppmv atmospheric CO2 concentration, and is therefore often considered an interesting analogue for near-future climate projections. Paleoenvironmental reconstructions indicate higher surface temperatures, decreasing tropical deserts, and a more humid climate in West Africa characterized by a strengthened West African Monsoon (WAM). Using model results from the second phase of the Pliocene Modelling Intercomparison Project (PlioMIP2) ensemble, we analyse changes of the WAM rainfall during the mPWP by comparing them with the control simulations for the pre-industrial period. The ensemble shows a robust increase in the summer rainfall over West Africa and the Sahara region, with an average increase of 2.5 mm/d, contrasted by a rainfall decrease over the equatorial Atlantic. An anomalous warming of the Sahara and deepening of the Saharan Heat Low, seen in >90 % of the models, leads to a strengthening of the WAM and an increased monsoonal flow into the continent. A similar warming of the Sahara is seen in future projections using both phase 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5). Though previous studies of future projections indicate a west–east drying–wetting contrast over the Sahel, PlioMIP2 simulations indicate a uniform rainfall increase in that region in warm climates characterized by increasing greenhouse gas forcing. We note that this effect will further depend on the long-term response of the vegetation to the CO2 forcing.
- Published
- 2021
41. Mid-Pliocene Atlantic Meridional Overturning Circulation simulated in PlioMIP2
- Author
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Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Otterå, Odd Helge, Nisancioglu, Kerim H., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Feng, Ran, Otto-Bliesner, Bette L., Brady, Esther, Chandan, Deepak, Peltier, W. Richard, Baatsen, Michiel L. J., von der Heydt, Anna S., Weiffenbach, Julia E., Stepanek, Christian, Lohmann, Gerrit, Zhang, Qiong, Li, Qiang, Chandler, Mark A., Sohl, Linda E., Haywood, Alan M., Hunter, Stephen J., Tindall, Julia C., Williams, Charles, Lunt, Daniel J., Chan, Wing-Le, Abe-Ouchi, Ayako, Zhang, Zhongshi, Li, Xiangyu, Guo, Chuncheng, Otterå, Odd Helge, Nisancioglu, Kerim H., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Feng, Ran, Otto-Bliesner, Bette L., Brady, Esther, Chandan, Deepak, Peltier, W. Richard, Baatsen, Michiel L. J., von der Heydt, Anna S., Weiffenbach, Julia E., Stepanek, Christian, Lohmann, Gerrit, Zhang, Qiong, Li, Qiang, Chandler, Mark A., Sohl, Linda E., Haywood, Alan M., Hunter, Stephen J., Tindall, Julia C., Williams, Charles, Lunt, Daniel J., Chan, Wing-Le, and Abe-Ouchi, Ayako
- Abstract
In the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), coupled climate models have been used to simulate an interglacial climate during the mid-Piacenzian warm period (mPWP; 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), poleward ocean heat transport and sea surface warming in the Atlantic simulated with these models. In PlioMIP2, all models simulate an intensified mid-Pliocene AMOC. However, there is no consistent response in the simulated Atlantic ocean heat transport nor in the depth of the Atlantic overturning cell. The models show a large spread in the simulated AMOC maximum, the Atlantic ocean heat transport and the surface warming in the North Atlantic. Although a few models simulate a surface warming of ∼ 8–12 ∘C in the North Atlantic, similar to the reconstruction from Pliocene Research, Interpretation and Synoptic Mapping (PRISM) version 4, most models appear to underestimate this warming. The large model spread and model–data discrepancies in the PlioMIP2 ensemble do not support the hypothesis that an intensification of the AMOC, together with an increase in northward ocean heat transport, is the dominant mechanism for the mid-Pliocene warm climate over the North Atlantic.
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- 2021
42. Unraveling the mechanisms and implications of a stronger mid-Pliocene AMOC in PlioMIP2.
- Author
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Weiffenbach, Julia E., Baatsen, Michiel L. J., Dijkstra, Henk A., von der Heydt, Anna S., Ayako Abe-Ouchi, Brady, Esther C., Wing-Le Chan, Chandan, Deepak, Chandler, Mark A., Contoux, Camille, Ran Feng, Chuncheng Guo, Zixuan Han, Haywood, Alan M., Qiang Li, Xiangyu Li, Lohmann, Gerrit, Lunt, Daniel J., Nisancioglu, Kerim H., and Otto-Bliesner, Bette L.
- Abstract
The mid-Pliocene warm period (3.264-3.025 Ma) is the most recent geological period in which the atmospheric CO2 concentration was approximately equal to the concentration we measure today (ca. 400 ppm). Sea surface temperature (SST) proxies indicate above-average warming over the North Atlantic in the mid-Pliocene with respect to the pre-industrial period, which may be linked to an intensified Atlantic Meridional Overturning Circulation (AMOC). Earlier results from the Pliocene 5 Model Intercomparison Project Phase 2 (PlioMIP2) show that the ensemble simulates a stronger AMOC in the mid-Pliocene than in the pre-industrial. However, no consistent relationship between the stronger mid-Pliocene AMOC and either the Atlantic northward ocean heat transport (OHT) or average North Atlantic SSTs has been found. In this study, we look further into the drivers and consequences of a stronger AMOC in mid-Pliocene compared to pre-industrial simulations in PlioMIP2. We find that all model simulations with a closed Bering Strait and Canadian Archipelago show reduced freshwater transport from the Arctic Ocean into the North Atlantic. The resulting increase in salinity in the subpolar North Atlantic and Labrador Sea drives the stronger AMOC in the mid-Pliocene. To investigate the dynamics behind the ensemble's variable response of the total Atlantic OHT to the stronger AMOC, we separate the Atlantic OHT into two components associated with either the overturning circulation or the wind-driven gyre circulation. While the ensemble mean of the overturning component increased significantly in magnitude in the mid-Pliocene, it is partly compensated by a reduction of the gyre component in the northern subtropical gyre region. This indicates that the lack of relationship between the total OHT and AMOC is due to changes in OHT by the subtropical gyre. The overturning and gyre components should therefore be considered separately to gain a more complete understanding of the OHT response to a stronger mid-Pliocene AMOC. In addition, we show that the AMOC exerts a stronger influence on North Atlantic SSTs in the mid-Pliocene than in the pre-industrial, providing a possible explanation for the improved agreement of the PlioMIP2 ensemble mean SSTs with reconstructions in the North Atlantic. [ABSTRACT FROM AUTHOR]
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- 2022
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43. Mid-Pliocene Atlantic Meridional Overturning Circulation simulated in PlioMIP2
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Zhang, Zhongshi, primary, Li, Xiangyu, additional, Guo, Chuncheng, additional, Otterå, Odd Helge, additional, Nisancioglu, Kerim H., additional, Tan, Ning, additional, Contoux, Camille, additional, Ramstein, Gilles, additional, Feng, Ran, additional, Otto-Bliesner, Bette L., additional, Brady, Esther, additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Weiffenbach, Julia E., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Zhang, Qiong, additional, Li, Qiang, additional, Chandler, Mark A., additional, Sohl, Linda E., additional, Haywood, Alan M., additional, Hunter, Stephen J., additional, Tindall, Julia C., additional, Williams, Charles, additional, Lunt, Daniel J., additional, Chan, Wing-Le, additional, and Abe-Ouchi, Ayako, additional
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- 2021
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44. Lessons from a high-CO2 world: an ocean view from ∼ 3 million years ago
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McClymont, Erin L., Ford, Heather L., Ho, Sze Ling, Tindall, Julia C., Haywood, Alan M., Alonso-Garcia, Montserrat, Bailey, Ian, Berke, Melissa A., Littler, Kate, Patterson, Molly O., Petrick, Benjamin, Peterse, Francien, Ravelo, A. Christina, De Schepper, Stijn, Swann, George E. A., Thirumalai, Kaustubh, Tierney, Jessica E., van der Weijst, Carolien, White, Sarah, Abe-Ouchi, Ayako, Baatsen, Michiel L. J., Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Feng, Ran, Guo, Chuncheng, von der Heydt, Anna S., Hunter, Stephen, Li, Xiangyi, Lohmann, Gerrit, Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Stepanek, Christian, and Zhang, Zhongshi
- Subjects
Global and Planetary Change ,Stratigraphy ,Palaeontology - Abstract
A range of future climate scenarios are projected for high atmospheric CO2 concentrations, given uncertainties over future human actions as well as potential environmental and climatic feedbacks. The geological record offers an opportunity to understand climate system response to a range of forcings and feedbacks which operate over multiple temporal and spatial scales. Here, we examine a single interglacial during the late Pliocene (KM5c, ca. 3.205±0.01 Ma) when atmospheric CO2 exceeded pre-industrial concentrations, but were similar to today and to the lowest emission scenarios for this century. As orbital forcing and continental configurations were almost identical to today, we are able to focus on equilibrium climate system response to modern and near-future CO2. Using proxy data from 32 sites, we demonstrate that global mean sea-surface temperatures were warmer than pre-industrial values, by ∼2.3 ∘C for the combined proxy data (foraminifera Mg∕Ca and alkenones), or by ∼3.2–3.4 ∘C (alkenones only). Compared to the pre-industrial period, reduced meridional gradients and enhanced warming in the North Atlantic are consistently reconstructed. There is broad agreement between data and models at the global scale, with regional differences reflecting ocean circulation and/or proxy signals. An uneven distribution of proxy data in time and space does, however, add uncertainty to our anomaly calculations. The reconstructed global mean sea-surface temperature anomaly for KM5c is warmer than all but three of the PlioMIP2 model outputs, and the reconstructed North Atlantic data tend to align with the warmest KM5c model values. Our results demonstrate that even under low-CO2 emission scenarios, surface ocean warming may be expected to exceed model projections and will be accentuated in the higher latitudes.
- Published
- 2020
45. Lessons from a high-CO2 world: an ocean view from ~ 3 million years ago
- Author
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McClymont, Erin L., Ford, Heather L., Ho, Sze Ling, Tindall, Julia C., Haywood, Alan M., Alonso-Garcia, Montserrat, Bailey, Ian, Berke, Melissa A., Littler, Kate, Patterson, Molly O., Petrick, Benjamin, Peterse, Francien, Ravelo, A. Christina, Risebrobakken, Bjørg, De Schepper, Stijn, Swann, George E. A., Thirumalai, Kaustubh, Tierney, Jessica E., van der Weijst, Carolien, White, Sarah, Abe-Ouchi, Ayako, Baatsen, Michiel L. J., Brady, Esther C., Chan, Wing-Le, Chandan, Deepak, Feng, Ran, Guo, Chuncheng, von der Heydt, Anna S., Hunter, Stephen, Li, Xiangyi, Lohmann, Gerrit, Nisancioglu, Kerim H., Otto-Bliesner, Bette L., Peltier, W. Richard, Stepanek, Christian, and Zhang, Zhongshi
- Abstract
A range of future climate scenarios are projected for high atmospheric CO2 concentrations, given uncertainties over future human actions as well as potential environmental and climatic feedbacks. The geological record offers an opportunity to understand climate system response to a range of forcings and feedbacks which operate over multiple temporal and spatial scales. Here, we examine a single interglacial during the late Pliocene (KM5c, ca. 3:205 0:01 Ma) when atmospheric CO2 exceeded pre-industrial concentrations, but were similar to today and to the lowest emission scenarios for this century. As orbital forcing and continental configurations were almost identical to today, we are able to focus on equilibrium climate system response to modern and near-future CO2. Using proxy data from 32 sites, we demonstrate that global mean sea-surface temperatures were warmer than pre-industrial values, by 2:3 C for the combined proxy data (foraminifera Mg=Ca and alkenones), or by 3:2–3.4 C (alkenones only). Compared to the preindustrial period, reduced meridional gradients and enhanced warming in the North Atlantic are consistently reconstructed. There is broad agreement between data and models at the global scale, with regional differences reflecting ocean circulation and/or proxy signals. An uneven distribution of proxy data in time and space does, however, add uncertainty to our anomaly calculations. The reconstructed global mean seasurface temperature anomaly for KM5c is warmer than all but three of the PlioMIP2 model outputs, and the reconstructed North Atlantic data tend to align with the warmest KM5c model values. Our results demonstrate that even under low-CO2 emission scenarios, surface ocean warming may be expected to exceed model projections and will be accentuated in the higher latitudes. FCT: SFRH/BPD/96960/2013, PTDC/MAR-PRO/3396/2014, CCMAR UID/Multi/04326/2019 info:eu-repo/semantics/publishedVersion
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- 2020
46. Evaluation of Arctic warming in mid-Pliocene climate simulations
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de Nooijer, Wesley, Zhang, Qiong, Li, Qiang, Zhang, Qiang, Li, Xiangyu, Zhang, Zhongshi, Guo, Chuncheng, Nisancioglu, Kerim H., Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Dowsett, Harry J., Stepanek, Christian, Lohmann, Gerrit, Otto-Bliesner, Bette L., Feng, Ran, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Baatsen, Michiel L. J., von Der Heydt, Anna S., Chandan, Deepak, Peltier, W. Richard, Abe-Ouchi, Ayako, Chan, Wing-Le, Kamae, Youichi, Brierley, Chris M., de Nooijer, Wesley, Zhang, Qiong, Li, Qiang, Zhang, Qiang, Li, Xiangyu, Zhang, Zhongshi, Guo, Chuncheng, Nisancioglu, Kerim H., Haywood, Alan M., Tindall, Julia C., Hunter, Stephen J., Dowsett, Harry J., Stepanek, Christian, Lohmann, Gerrit, Otto-Bliesner, Bette L., Feng, Ran, Sohl, Linda E., Chandler, Mark A., Tan, Ning, Contoux, Camille, Ramstein, Gilles, Baatsen, Michiel L. J., von Der Heydt, Anna S., Chandan, Deepak, Peltier, W. Richard, Abe-Ouchi, Ayako, Chan, Wing-Le, Kamae, Youichi, and Brierley, Chris M.
- Abstract
Palaeoclimate simulations improve our understanding of the climate, inform us about the performance of climate models in a different climate scenario, and help to identify robust features of the climate system. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), derived from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The PlioMIP2 ensemble simulates Arctic (60-90 degrees N) annual mean surface air temperature (SAT) increases of 3.7 to 11.6 degrees C compared to the pre-industrial period, with a multimodel mean (MMM) increase of 7.2 degrees C. The Arctic warming amplification ratio relative to global SAT anomalies in the ensemble ranges from 1.8 to 3.1 (MMM is 2.3). Sea ice extent anomalies range from -3.0 to -10.4 x 10(6) km(2), with a MMM anomaly of -5.6 x 10 6 km(2), which constitutes a decrease of 53 % compared to the pre-industrial period. The majority (11 out of 16) of models simulate summer seaice-free conditions (<= 1 x 10(6) km(2)) in their mPWP simulation. The ensemble tends to underestimate SAT in the Arctic when compared to available reconstructions, although the degree of underestimation varies strongly between the simulations. The simulations with the highest Arctic SAT anomalies tend to match the proxy dataset in its current form better. The ensemble shows some agreement with reconstructions of sea ice, particularly with regard to seasonal sea ice. Large uncertainties limit the confidence that can be placed in the findings and the compatibility of the different proxy datasets. We show that while reducing uncertainties in the reconstructions could decrease the SAT data-model discord substantially, further improvements are likely to be found in enhanced boundary conditions or model physics. Lastly, we compare the Arctic warming in the mPWP to projections of future Arctic warming and find that the PlioMIP2 ensemble simulates greater Arctic amplification than CMIP5 future climate si
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- 2020
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47. The Pliocene Model Intercomparison Project Phase 2 : large-scale climate features and climate sensitivity
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Haywood, Alan M., Tindall, Julia C., Dowsett, Harry J., Dolan, Aisling M., Foley, Kevin M., Hunter, Stephen J., Hill, Daniel J., Chan, Wing-Le, Abe-Ouchi, Ayako, Stepanek, Christian, Lohmann, Gerrit, Chandan, Deepak, Peltier, W. Richard, Tan, Ning, Contoux, Camille, Ramstein, Gilles, Li, Xiangyu, Zhang, Zhongshi, Guo, Chuncheng, Nisancioglu, Kerim H., Zhang, Qiong, Li, Qiang, Kamae, Youichi, Chandler, Mark A., Sohl, Linda E., Otto-Bliesner, Bette L., Feng, Ran, Brady, Esther C., von der Heydt, Anna S., Baatsen, Michiel L. J., Lunt, Daniel J., Haywood, Alan M., Tindall, Julia C., Dowsett, Harry J., Dolan, Aisling M., Foley, Kevin M., Hunter, Stephen J., Hill, Daniel J., Chan, Wing-Le, Abe-Ouchi, Ayako, Stepanek, Christian, Lohmann, Gerrit, Chandan, Deepak, Peltier, W. Richard, Tan, Ning, Contoux, Camille, Ramstein, Gilles, Li, Xiangyu, Zhang, Zhongshi, Guo, Chuncheng, Nisancioglu, Kerim H., Zhang, Qiong, Li, Qiang, Kamae, Youichi, Chandler, Mark A., Sohl, Linda E., Otto-Bliesner, Bette L., Feng, Ran, Brady, Esther C., von der Heydt, Anna S., Baatsen, Michiel L. J., and Lunt, Daniel J.
- Abstract
The Pliocene epoch has great potential to improve our understanding of the long-term climatic and environmental consequences of an atmospheric CO2 concentration near similar to 400 parts per million by volume. Here we present the large-scale features of Pliocene climate as simulated by a new ensemble of climate models of varying complexity and spatial resolution based on new reconstructions of boundary conditions (the Pliocene Model Intercomparison Project Phase 2; PlioMIP2). As a global annual average, modelled surface air temperatures increase by between 1.7 and 5.2 degrees C relative to the pre-industrial era with a multi-model mean value of 3.2 degrees C. Annual mean total precipitation rates increase by 7 % (range: 2 %-13 %). On average, surface air temperature (SAT) increases by 4.3 degrees C over land and 2.8 degrees C over the oceans. There is a clear pattern of polar amplification with warming polewards of 60 degrees N and 60 degrees S exceeding the global mean warming by a factor of 2.3. In the Atlantic and Pacific oceans, meridional temperature gradients are reduced, while tropical zonal gradients remain largely unchanged. There is a statistically significant relationship between a model's climate response associated with a doubling in CO2 (equilibrium climate sensitivity; ECS) and its simulated Pliocene surface temperature response. The mean ensemble Earth system response to a doubling of CO2 (including ice sheet feedbacks) is 67 % greater than ECS; this is larger than the increase of 47 % obtained from the PlioMIP1 ensemble. Proxy-derived estimates of Pliocene sea surface temperatures are used to assess model estimates of ECS and give an ECS range of 2.6-4.8 degrees C. This result is in general accord with the ECS range presented by previous Intergovernmental Panel on Climate Change (IPCC) Assessment Reports.
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- 2020
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48. Evaluation of Arctic warming in mid-Pliocene climate simulations
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de Nooijer, Wesley, primary, Zhang, Qiong, additional, Li, Qiang, additional, Zhang, Qiang, additional, Li, Xiangyu, additional, Zhang, Zhongshi, additional, Guo, Chuncheng, additional, Nisancioglu, Kerim H., additional, Haywood, Alan M., additional, Tindall, Julia C., additional, Hunter, Stephen J., additional, Dowsett, Harry J., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Otto-Bliesner, Bette L., additional, Feng, Ran, additional, Sohl, Linda E., additional, Chandler, Mark A., additional, Tan, Ning, additional, Contoux, Camille, additional, Ramstein, Gilles, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Abe-Ouchi, Ayako, additional, Chan, Wing-Le, additional, Kamae, Youichi, additional, and Brierley, Chris M., additional
- Published
- 2020
- Full Text
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49. The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity
- Author
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Haywood, Alan M., primary, Tindall, Julia C., additional, Dowsett, Harry J., additional, Dolan, Aisling M., additional, Foley, Kevin M., additional, Hunter, Stephen J., additional, Hill, Daniel J., additional, Chan, Wing-Le, additional, Abe-Ouchi, Ayako, additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Tan, Ning, additional, Contoux, Camille, additional, Ramstein, Gilles, additional, Li, Xiangyu, additional, Zhang, Zhongshi, additional, Guo, Chuncheng, additional, Nisancioglu, Kerim H., additional, Zhang, Qiong, additional, Li, Qiang, additional, Kamae, Youichi, additional, Chandler, Mark A., additional, Sohl, Linda E., additional, Otto-Bliesner, Bette L., additional, Feng, Ran, additional, Brady, Esther C., additional, von der Heydt, Anna S., additional, Baatsen, Michiel L. J., additional, and Lunt, Daniel J., additional
- Published
- 2020
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50. Mid-Pliocene Atlantic Meridional Overturning Circulation simulated in PlioMIP2
- Author
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Zhang, Zhongshi, primary, Li, Xiangyu, additional, Guo, Chuncheng, additional, Otterå, Odd Helge, additional, Nisancioglu, Kerim H., additional, Tan, Ning, additional, Contoux, Camille, additional, Ramstein, Gilles, additional, Feng, Ran, additional, Otto-Bliesner, Bette L., additional, Brady, Esther, additional, Chandan, Deepak, additional, Peltier, W. Richard, additional, Baatsen, Michiel L. J., additional, von der Heydt, Anna S., additional, Weiffenbach, Julia E., additional, Stepanek, Christian, additional, Lohmann, Gerrit, additional, Zhang, Qiong, additional, Li, Qiang, additional, Chandler, Mark A., additional, Sohl, Linda E., additional, Haywood, Alan M., additional, Hunter, Stephen J., additional, Tindall, Julia C., additional, Williams, Charles, additional, Lunt, Daniel J., additional, Chan, Wing-Le, additional, and Abe-Ouchi, Ayako, additional
- Published
- 2020
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