141 results on '"Rosenbloom, N. A."'
Search Results
2. Coupled Climate Responses to Recent Australian Wildfire and COVID‐19 Emissions Anomalies Estimated in CESM2
- Author
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Fasullo, J. T., primary, Rosenbloom, N., additional, Buchholz, R. R., additional, Danabasoglu, G., additional, Lawrence, D. M., additional, and Lamarque, J.‐F., additional
- Published
- 2021
- Full Text
- View/download PDF
3. The VEMAP Integrated Database for Modelling United States Ecosystem/Vegetation Sensitivity to Climate Change
- Author
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Kittel, T. G. F., Rosenbloom, N. A., Painter, T. H., and Schimel, D. S.
- Published
- 1995
- Full Text
- View/download PDF
4. Evaluating the large-scale hydrological cycle response within the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) ensemble
- Author
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Han, Z, Zhang, Q, Li, Q, Feng, R, Haywood, AM, Tindall, JC, Hunter, SJ, Otto-Bliesner, BL, Brady, EC, Rosenbloom, N, Zhang, Z, Li, X, Guo, C, Nisancioglu, KH, Stepanek, C, Lohmann, G, Sohl, LE, Chandler, MA, Tan, N, Ramstein, G, Baatsen, MLJ, von der Heydt, AS, Chandan, D, Peltier, WR, Williams, CJR, Lunt, DJ, Cheng, J, Wen, Q, Burls, NJ, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation du climat (CLIM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Sub Dynamics Meteorology, Sub Physical Oceanography, Marine and Atmospheric Research, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), This research has been supported by the Swedish Research Council (Vetenskapsrådet, grant nos. 2013- 06476 and 2017-04232). The article processing charges for this open-access publication were covered by Stockholm University, Zixuan Han acknowledges financial support from the National Natural Science Foundation of China (grant no. 42130610), the Fundamental Research Funds for the Central Universities (grant no. B210201009), and the National Key R&D Program of China (grant no. 2017YFC1502303). Jianbo Cheng acknowledges financial support from the National Natural Science Foundation of China (grant no. 42005012) and the Natural Science Foundation of Jiangsu Province (grant no. BK20201058). Qin Wen acknowledges financial support from the National Natural Science Foundation of China (grant no. 42106016) and a project funded by the China Postdoctoral Science Foundation (grant no. 2021M691623). The EC-Earth3 model simulations and the data analysis were performed using the ECMWF computing and archive facilities and the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Centre (NSC), which is partially funded by the Swedish Research Council through grant agreement no. 2018-05973. Charles J. R. Williams acknowledges financial support from the UK Natural Environment Research Council within the framework of the SWEET (Super-Warm Early Eocene Temperatures) project (grant no. NE/P01903X/1). Natalie J. Burls acknowledges support from the National Science Foundation (NSF, grant nos. AGS-1844380 and OCN-2002448) and the Alfred P. Sloan Foundation (as a research fellow). Ran Feng acknowledges sponsorship from the U.S. National Science Foundation (grant nos. 1903650 and 1814029). The contributions of Bette L. Otto-Bliesner, Esther C. Brady, and Nan Rosenbloom are based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the NSF under cooperative agreement no. 1852977. The CESM project is primarily supported by the National Science Foundation (NSF). Computing and data storage resources for the CESM and CCSM4 simulations, including the Cheyenne supercomputer (https://doi.org/10.5065/D6RX99HX), were provided by the Computational and Information Systems Laboratory (CISL) at NCAR. Xiangyu Li acknowledges financial support from the National Natural Science Foundation of China (NSFC, grant no. 42005042) and the China Scholarship Council (grant no. 201804910023). The NorESM simulations benefitted from resources provided by UNINETT Sigma2 – the national infrastructure for high-performance computing and data storage in Norway. The work by Anna S. von der Heydt and Michiel L. J. Baatsen was carried out in the framework of the Netherlands Earth System Science Centre (NESSC) program, which is financially supported by the Ministry of Education, Culture and Science (OCW grant no. 024.002.001). Simulations with CCSM4-Utrecht were performed at the SURFsara Dutch national computing facilities and were sponsored by NWO-EW (Netherlands Organisation for Scientific Research, Exact Sciences, and project nos. 17189 and 2020.022). Christian Stepanek and Gerrit Lohmann acknowledge computational resources from the Computing and Data Centre of the Alfred Wegener Institute, Helmholtz-Zentrum für Polar- und Meeresforschung. Christian Stepanek and Gerrit Lohmann also acknowledge funding from the Helmholtz Climate Initiative REKLIM and the Alfred Wegener Institute's 'Changing Earth-Sustaining our Future' research program. The PRISM4 reconstruction and boundary conditions used in PlioMIP2 were funded by the U.S. Geological Survey Climate and Land Use Change Research and Development Program. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government.
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Global and Planetary Change ,Stratigraphy ,Palaeontology ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment - Abstract
International audience; 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
5. Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6
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Tebaldi, C, Debeire, K, Eyring, V, Fischer, E, Fyfe, J, Friedlingstein, P, Knutti, R, Lowe, J, O'Neill, B, Sanderson, B, van Vuuren, D, Riahi, K, Meinshausen, M, Nicholls, Z, Tokarska, KB, Hurtt, G, Kriegler, E, Lamarque, J-F, Meehl, G, Moss, R, Bauer, SE, Boucher, O, Brovkin, V, Byun, Y-H, Dix, M, Gualdi, S, Guo, H, John, JG, Kharin, S, Kim, Y, Koshiro, T, Ma, L, Olivie, D, Panickal, S, Qiao, F, Rong, X, Rosenbloom, N, Schupfner, M, Seferian, R, Sellar, A, Semmler, T, Shi, X, Song, Z, Steger, C, Stouffer, R, Swart, N, Tachiiri, K, Tang, Q, Tatebe, H, Voldoire, A, Volodin, E, Wyser, K, Xin, X, Yang, S, Yu, Y, Ziehn, T, Tebaldi, C, Debeire, K, Eyring, V, Fischer, E, Fyfe, J, Friedlingstein, P, Knutti, R, Lowe, J, O'Neill, B, Sanderson, B, van Vuuren, D, Riahi, K, Meinshausen, M, Nicholls, Z, Tokarska, KB, Hurtt, G, Kriegler, E, Lamarque, J-F, Meehl, G, Moss, R, Bauer, SE, Boucher, O, Brovkin, V, Byun, Y-H, Dix, M, Gualdi, S, Guo, H, John, JG, Kharin, S, Kim, Y, Koshiro, T, Ma, L, Olivie, D, Panickal, S, Qiao, F, Rong, X, Rosenbloom, N, Schupfner, M, Seferian, R, Sellar, A, Semmler, T, Shi, X, Song, Z, Steger, C, Stouffer, R, Swart, N, Tachiiri, K, Tang, Q, Tatebe, H, Voldoire, A, Volodin, E, Wyser, K, Xin, X, Yang, S, Yu, Y, and Ziehn, T
- Abstract
The Scenario Model Intercomparison Project (ScenarioMIP) defines and coordinates the main set of future climate projections, based on concentration-driven simulations, within the Coupled Model Intercomparison Project phase 6 (CMIP6). This paper presents a range of its outcomes by synthesizing results from the participating global coupled Earth system models. We limit our scope to the analysis of strictly geophysical outcomes: mainly global averages and spatial patterns of change for surface air temperature and precipitation. We also compare CMIP6 projections to CMIP5 results, especially for those scenarios that were designed to provide continuity across the CMIP phases, at the same time highlighting important differences in forcing composition, as well as in results. The range of future temperature and precipitation changes by the end of the century (2081–2100) encompassing the Tier 1 experiments based on the Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) and SSP1-1.9 spans a larger range of outcomes compared to CMIP5, due to higher warming (by close to 1.5 ∘C) reached at the upper end of the 5 %–95 % envelope of the highest scenario (SSP5-8.5). This is due to both the wider range of radiative forcing that the new scenarios cover and the higher climate sensitivities in some of the new models compared to their CMIP5 predecessors. Spatial patterns of change for temperature and precipitation averaged over models and scenarios have familiar features, and an analysis of their variations confirms model structural differences to be the dominant source of uncertainty. Models also differ with respect to the size and evolution of internal variability as measured by individual models' initial condition ensemble spreads, according to a set of initial condition ensemble simulations available under SSP3-7.0. These experiments suggest a tendency for internal variability to decrease along the course of the century in this scenario
- Published
- 2021
6. Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6
- Author
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Tebaldi, C., Debeire, K., Eyring, V., Fischer, E., Fyfe, J., Friedlingstein, P., Knutti, R., Lowe, J., O'Neill, B., Sanderson, B., van Vuuren, D., Riahi, K., Meinshausen, M., Nicholls, Z., Tokarska, K. B., Hurtt, G., Kriegler, E., Lamarque, J.-F., Meehl, G., Moss, R., Bauer, S. E., Boucher, O., Brovkin, V., Byun, Y.-H., Dix, M., Gualdi, S., Guo, H., John, J. G., Kharin, S., Kim, Y., Koshiro, T., Ma, L., Olivié, D., Panickal, S., Qiao, F., Rong, X., Rosenbloom, N., Schupfner, M., Séférian, R., Sellar, A., Semmler, T., Shi, X., Song, Z., Steger, C., Stouffer, R., Swart, N., Tachiiri, K., Tang, Q., Tatebe, H., Voldoire, A., Volodin, E., Wyser, K., Xin, X., Yang, S., Yu, Y., Ziehn, T., Tebaldi, C., Debeire, K., Eyring, V., Fischer, E., Fyfe, J., Friedlingstein, P., Knutti, R., Lowe, J., O'Neill, B., Sanderson, B., van Vuuren, D., Riahi, K., Meinshausen, M., Nicholls, Z., Tokarska, K. B., Hurtt, G., Kriegler, E., Lamarque, J.-F., Meehl, G., Moss, R., Bauer, S. E., Boucher, O., Brovkin, V., Byun, Y.-H., Dix, M., Gualdi, S., Guo, H., John, J. G., Kharin, S., Kim, Y., Koshiro, T., Ma, L., Olivié, D., Panickal, S., Qiao, F., Rong, X., Rosenbloom, N., Schupfner, M., Séférian, R., Sellar, A., Semmler, T., Shi, X., Song, Z., Steger, C., Stouffer, R., Swart, N., Tachiiri, K., Tang, Q., Tatebe, H., Voldoire, A., Volodin, E., Wyser, K., Xin, X., Yang, S., Yu, Y., and Ziehn, T.
- Abstract
The Scenario Model Intercomparison Project (ScenarioMIP) defines and coordinates the main set of future climate projections, based on concentration-driven simulations, within the Coupled Model Intercomparison Project phase 6 (CMIP6). This paper presents a range of its outcomes by synthesizing results from the participating global coupled Earth system models. We limit our scope to the analysis of strictly geophysical outcomes: mainly global averages and spatial patterns of change for surface air temperature and precipitation. We also compare CMIP6 projections to CMIP5 results, especially for those scenarios that were designed to provide continuity across the CMIP phases, at the same time highlighting important differences in forcing composition, as well as in results. The range of future temperature and precipitation changes by the end of the century (2081–2100) encompassing the Tier 1 experiments based on the Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) and SSP1-1.9 spans a larger range of outcomes compared to CMIP5, due to higher warming (by close to 1.5 ∘C) reached at the upper end of the 5 %–95 % envelope of the highest scenario (SSP5-8.5). This is due to both the wider range of radiative forcing that the new scenarios cover and the higher climate sensitivities in some of the new models compared to their CMIP5 predecessors. Spatial patterns of change for temperature and precipitation averaged over models and scenarios have familiar features, and an analysis of their variations confirms model structural differences to be the dominant source of uncertainty. Models also differ with respect to the size and evolution of internal variability as measured by individual models' initial condition ensemble spreads, according to a set of initial condition ensemble simulations available under SSP3-7.0. These experiments suggest a tendency for internal variability to decrease along the course of the century in this scenario, a result
- Published
- 2021
7. Evaluating the Dominant Components of Warming in Pliocene Climate Simulations
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Hill, D. J, Haywood, A. M, Lunt, D. J, Hunter, S. J, Bragg, F. J, Contoux, C, Stepanek, C, Sohl, L, Rosenbloom, N. A, Chan, W.-L, Kamae, Y, Zhang, Z, Abe-Ouchi, A, Chandler, M. A, Jost, A, Lohmann, G, Otto-Bliesner, B. L, Ramstein, G, and Ueda, H
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Meteorology And Climatology - Abstract
The Pliocene Model Intercomparison Project (PlioMIP) is the first coordinated climate model comparison for a warmer palaeoclimate with atmospheric CO2 significantly higher than pre-industrial concentrations. The simulations of the mid-Pliocene warm period show global warming of between 1.8 and 3.6 C above pre-industrial surface air temperatures, with significant polar amplification. Here we perform energy balance calculations on all eight of the coupled ocean-atmosphere simulations within PlioMIP Experiment 2 to evaluate the causes of the increased temperatures and differences between the models. In the tropics simulated warming is dominated by greenhouse gas increases, with the cloud component of planetary albedo enhancing the warming in most of the models, but by widely varying amounts. The responses to mid-Pliocene climate forcing in the Northern Hemisphere midlatitudes are substantially different between the climate models, with the only consistent response being a warming due to increased greenhouse gases. In the high latitudes all the energy balance components become important, but the dominant warming influence comes from the clear sky albedo, only partially offset by the increases in the cooling impact of cloud albedo. This demonstrates the importance of specified ice sheet and high latitude vegetation boundary conditions and simulated sea ice and snow albedo feedbacks. The largest components in the overall uncertainty are associated with clouds in the tropics and polar clear sky albedo, particularly in sea ice regions. These simulations show that albedo feedbacks, particularly those of sea ice and ice sheets, provide the most significant enhancements to high latitude warming in the Pliocene.
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- 2014
- Full Text
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8. Large-Scale Features of Pliocene Climate: Results from the Pliocene Model Intercomparison Project
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Haywood, A. M, Hill, D.J, Dolan, A. M, Otto-Bliesner, B. L, Bragg, F, Chan, W.-L, Chandler, M. A, Contoux, C, Dowsett, H. J, Jost, A, Kamae, Y, Lohmann, G, Lunt, D. J, Abe-Ouchi, A, Pickering, S. J, Ramstein, G, Rosenbloom, N. A, Salzmann, U, Sohl, L, Stepanek, C, Ueda, H, Yan, Q, and Zhang, Z
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Meteorology And Climatology - Abstract
Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied.Whilst numerical models have shed light on the nature of climate at the time, uncertainties in their predictions have not been systematically examined. The Pliocene Model Intercomparison Project quantifies uncertainties in model outputs through a coordinated multi-model and multi-mode data intercomparison. Whilst commonalities in model outputs for the Pliocene are clearly evident, we show substantial variation in the sensitivity of models to the implementation of Pliocene boundary conditions. Models appear able to reproduce many regional changes in temperature reconstructed from geological proxies. However, data model comparison highlights that models potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations in the time-averaged proxy data currently available must be addressed. Furthermore, sensitivity tests exploring the known unknowns in modelling Pliocene climate specifically relevant to the high latitudes are essential (e.g. palaeogeography, gateways, orbital forcing and trace gasses). Estimates of longer-term sensitivity to CO2 (also known as Earth System Sensitivity; ESS), support previous work suggesting that ESS is greater than Climate Sensitivity (CS), and suggest that the ratio of ESS to CS is between 1 and 2, with a "best" estimate of 1.5.
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- 2013
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9. Nonlinear Response of Extreme Precipitation to Warming in CESM1
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Pendergrass, A. G., primary, Coleman, D. B., additional, Deser, C., additional, Lehner, F., additional, Rosenbloom, N., additional, and Simpson, I. R., additional
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- 2019
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10. ANTEPARTUM DIAGNOSIS AND OUTCOME OF LOWER URINARY TRACT OBSTRUCTION
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Murphy, K.E., Grisaru-Granovsky, S., Seaward, P.G.R., Geary, D., McLorie, G., Windrim, R., Rosenbloom, N., and Ryan, G.
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- 1998
11. Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives
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Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, McGee, William David, Albani, S., Mahowald, N. M., Winckler, G., Anderson, R. F., Bradtmiller, L. I., Delmonte, B., François, R., Goman, M., Heavens, N. G., Hesse, P. P., Hovan, S. A., Kang, S. G., Kohfeld, K. E., Lu, H., Maggi, V., Mason, J. A., Mayewski, P. A., Miao, X., Otto-Bliesner, B. L., Perry, A. T., Pourmand, A., Roberts, H. M., Rosenbloom, N., Stevens, T., Sun, J., Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, McGee, William David, Albani, S., Mahowald, N. M., Winckler, G., Anderson, R. F., Bradtmiller, L. I., Delmonte, B., François, R., Goman, M., Heavens, N. G., Hesse, P. P., Hovan, S. A., Kang, S. G., Kohfeld, K. E., Lu, H., Maggi, V., Mason, J. A., Mayewski, P. A., Miao, X., Otto-Bliesner, B. L., Perry, A. T., Pourmand, A., Roberts, H. M., Rosenbloom, N., Stevens, T., and Sun, J.
- Abstract
Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP (Dust Indicators and Records from Terrestrial and MArine Palaeoenvironments) paleodust data sets in the last 2 decades provided a benchmark for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust data set that builds on the positive experience of DIRTMAP and takes into account new scientific challenges by providing a concise and accessible data set of temporally resolved records of dust mass accumulation rates and particle grain size distributions. We consider data from ice cores, marine sediments, loess–paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows the investigation of the potential, uncertainties, and confidence level of dust mass accumulation rate reconstructions and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 45 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggests that minimum dust fluxes are likely observed during the early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize data sets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate
- Published
- 2018
12. Predicting Near-Term Changes in the Earth System: A Large Ensemble of Initialized Decadal Prediction Simulations Using the Community Earth System Model
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Yeager, S. G., primary, Danabasoglu, G., additional, Rosenbloom, N. A., additional, Strand, W., additional, Bates, S. C., additional, Meehl, G. A., additional, Karspeck, A. R., additional, Lindsay, K., additional, Long, M. C., additional, Teng, H., additional, and Lovenduski, N. S., additional
- Published
- 2018
- Full Text
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13. The climate response of the Indo-Pacific warm pool to glacial sea level
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Di Nezio, PN, Timmerman, A, Tierney, JE, Jin, F-F, Otto-Bliesner, B, Rosenbloom, N, Mapes, B, Neale, R, Ivanovic, RF, and Montenegro, A
- Abstract
Growing climate proxy evidence suggests that changes in sea level are important drivers of tropical climate change on glacial--interglacial time-scales. These paleodata suggest that rainfall patterns over the Indo-Pacific Warm Pool (IPWP) are highly sensitive to the landmass configuration of the Maritime Continent, and that lowered sea level contributed to large-scale drying during the Last Glacial Maximum (LGM, ca. 21,000 years before present). Using the Community Earth System Model Version 1.2 (CESM1) we investigate in detail the mechanisms by which lowered sea level influenced the climate of the IPWP during the LGM. The CESM1 simulations show that, in agreement with previous hypotheses, changes in atmospheric circulation are initiated by the exposure of the Sunda and Sahul shelves. Ocean dynamical processes amplify the changes in atmospheric circulation by increasing the east-west sea-surface temperature (SST) gradient along the equatorial Indian Ocean. The coupled mechanism driving this response is akin to the Bjerknes feedback, and results in a large-scale climatic reorganization over the Indian Ocean with impacts extending from east Africa to the western tropical Pacific. Exposure of Sahul shelf and the associated changes in surface albedo play a key role because it is more effective at exciting the positive feedback than exposure of the Sunda shelf. This mechanism could explain the pattern of dry (wet) eastern (western) Indian Ocean identified in climate proxies and LGM simulations. However, this response also requires a strengthened SST gradient along the equatorial Indian Ocean, and it is currently unclear whether this is detectable in marine paleoreconstructions. Strategies to resolve this issue are discussed.
- Published
- 2016
14. Arctic sea ice simulation in the PlioMIP ensemble
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Howell, F. W., Haywood, A. M., Otto-Bliesner, B. L., Bragg, F., Chan, W-L., Chandler, M. A., Contoux, C., Kamae, Y., Abe-Ouchi, A., Rosenbloom, N. A., Stepanek, Christian, Zhang, Z., Howell, F. W., Haywood, A. M., Otto-Bliesner, B. L., Bragg, F., Chan, W-L., Chandler, M. A., Contoux, C., Kamae, Y., Abe-Ouchi, A., Rosenbloom, N. A., Stepanek, Christian, and Zhang, Z.
- Abstract
Eight general circulation models have simulated the mid-Pliocene warm period (mid-Pliocene, 3.264 to 3.025 Ma) as part of the Pliocene Modelling Intercomparison Project (PlioMIP). Here, we analyse and compare their simulation of Arctic sea ice for both the pre-industrial period and the mid-Pliocene. Mid-Pliocene sea ice thickness and extent is reduced, and the model spread of extent is more than twice the pre-industrial spread in some summer months. Half of the PlioMIP models simulate ice-free conditions in the mid-Pliocene. This spread amongst the ensemble is in line with the uncertainties amongst proxy reconstructions for mid-Pliocene sea ice extent. Correlations between mid-Pliocene Arctic temperatures and sea ice extents are almost twice as strong as the equivalent correlations for the pre-industrial simulations. The need for more comprehensive sea ice proxy data is highlighted, in order to better compare model performances.
- Published
- 2016
15. Twelve thousand years of dust : the Holocene global dust cycle constrained by natural archives
- Author
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Albani, S, Mahowald, N M, Winckler, G, Anderson, R F, Bradtmiller, L I, Delmonte, B, François, R, Goman, M, Heavens, N G, Hesse, P P, Hovan, S A, Kang, S G, Kohfeld, K E, Lu, H, Maggi, V, Mason, A, Mayewski, P A, McGee, D, Miao, X, Otto-Bliesner, L, Perry, A T, Pourmand, A, Roberts, H M, Rosenbloom, N, Stevens, Thomas, Sun, J, Albani, S, Mahowald, N M, Winckler, G, Anderson, R F, Bradtmiller, L I, Delmonte, B, François, R, Goman, M, Heavens, N G, Hesse, P P, Hovan, S A, Kang, S G, Kohfeld, K E, Lu, H, Maggi, V, Mason, A, Mayewski, P A, McGee, D, Miao, X, Otto-Bliesner, L, Perry, A T, Pourmand, A, Roberts, H M, Rosenbloom, N, Stevens, Thomas, and Sun, J
- Abstract
Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP paleodust datasets in the last two decades provided a target for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust dataset that moves on from the positive experience of DIRTMAP and takes into account new scientific challenges, by providing a concise and accessible dataset of temporally resolved records of dust mass accumulation rates and particle grain-size distributions. We consider data from ice cores, marine sediments, loess/paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows investigation of the potential, uncertainties and confidence level of dust mass accumulation rates reconstructions, and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 43 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggest that minimum dust fluxes are likely observed during the Early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize datasets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate the mass balance and variability of the global dust cycle during the Holocene, w
- Published
- 2015
- Full Text
- View/download PDF
16. Using results from the PlioMIP ensemble to investigate the Greenland Ice Sheet during the mid-Pliocene Warm Period
- Author
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Dolan, A. M., Hunter, S. J., Hill, D. J., Haywood, A. M., Koenig, S. J., Otto-Bliesner, B. L., Abe-Ouchi, A., Bragg, F., Chan, W.-L., Chandler, M. A., Contoux, C., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Ramstein, G., Rosenbloom, N. A., Sohl, L., Stepanek, Christian, Ueda, H., Yan, Q., Zhang, Z., Dolan, A. M., Hunter, S. J., Hill, D. J., Haywood, A. M., Koenig, S. J., Otto-Bliesner, B. L., Abe-Ouchi, A., Bragg, F., Chan, W.-L., Chandler, M. A., Contoux, C., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Ramstein, G., Rosenbloom, N. A., Sohl, L., Stepanek, Christian, Ueda, H., Yan, Q., and Zhang, Z.
- Abstract
During an interval of the Late Pliocene, referred to here as the mid-Pliocene Warm Period (mPWP; 3.264 to 3.025 million years ago), global mean temperature was similar to that predicted for the end of this century, and atmospheric carbon dioxide concentrations were higher than pre-industrial levels. Sea level was also higher than today, implying a significant reduction in the extent of the ice sheets. Thus, the mPWP provides a natural laboratory in which to investigate the long-term response of the Earth's ice sheets and sea level in a warmer-than-present-day world. At present, our understanding of the Greenland ice sheet during the mPWP is generally based upon predictions using single climate and ice sheet models. Therefore, it is essential that the model dependency of these results is assessed. The Pliocene Model Intercomparison Project (PlioMIP) has brought together nine international modelling groups to simulate the warm climate of the Pliocene. Here we use the climatological fields derived from the results of the 15 PlioMIP climate models to force an offline ice sheet model. We show that mPWP ice sheet reconstructions are highly dependent upon the forcing climatology used, with Greenland reconstructions ranging from an ice-free state to a near-modern ice sheet. An analysis of the surface albedo variability between the climate models over Greenland offers insights into the drivers of inter-model differences. As we demonstrate that the climate model dependency of our results is high, we highlight the necessity of data-based constraints of ice extent in developing our understanding of the mPWP Greenland ice sheet.
- Published
- 2015
17. Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives
- Author
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Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, McGee, David, Albani, S., Mahowald, N. M., Winckler, G., Anderson, R. F., Bradtmiller, L. I., Delmonte, B., François, R., Goman, M., Heavens, N. G., Hesse, P. P., Hovan, S. A., Kang, S. G., Kohfeld, K. E., Lu, H., Maggi, V., Mason, J. A., Mayewski, P. A., Miao, X., Otto-Bliesner, B. L., Perry, A. T., Pourmand, A., Roberts, H. M., Rosenbloom, N., Stevens, T., Sun, J., McGee, William David, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, McGee, David, Albani, S., Mahowald, N. M., Winckler, G., Anderson, R. F., Bradtmiller, L. I., Delmonte, B., François, R., Goman, M., Heavens, N. G., Hesse, P. P., Hovan, S. A., Kang, S. G., Kohfeld, K. E., Lu, H., Maggi, V., Mason, J. A., Mayewski, P. A., Miao, X., Otto-Bliesner, B. L., Perry, A. T., Pourmand, A., Roberts, H. M., Rosenbloom, N., Stevens, T., Sun, J., and McGee, William David
- Abstract
Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP (Dust Indicators and Records from Terrestrial and MArine Palaeoenvironments) paleodust data sets in the last 2 decades provided a benchmark for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust data set that builds on the positive experience of DIRTMAP and takes into account new scientific challenges by providing a concise and accessible data set of temporally resolved records of dust mass accumulation rates and particle grain size distributions. We consider data from ice cores, marine sediments, loess–paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows the investigation of the potential, uncertainties, and confidence level of dust mass accumulation rate reconstructions and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 45 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggests that minimum dust fluxes are likely observed during the early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize data sets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate, National Science Foundation (U.S.) (Grant 0932946), National Science Foundation (U.S.) (Grant 1003509), United States. Dept. of Energy (DOE-SC00006735)
- Published
- 2015
18. Challenges in reconstructing terrestrial warming of the Pliocene revealed by data-model discord
- Author
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Salzmann, U., Dolan, A. M., Haywood, A. M., Chan, W.-L., Voss, J., Hill, D. J., Lunt, D. J., Abe-Ouchi, A., Otto-Bliesner, B., Bragg, F., Chandler, M. A., Contoux, C., Dowsett, H. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Pickering, S. J., Pound, M. J., Ramstein, G., Rosenbloom, N. A., Sohl, L., Stepanek, Christian, Ueda, H., and Zhang, Z.
- Abstract
Comparing simulations of key warm periods in Earth history with contemporaneous geological proxy data is a useful approach for evaluating the ability of climate models to simulate warm, high-CO2 climates that are unprecedented in the more recent past. Here we use a global data set of confidence-assessed, proxy-based temperature estimates and biome reconstructions to assess the ability of eight models to simulate warm terrestrial climates of the Pliocene epoch. The Late Pliocene, 3.6–2.6 million years ago, is an accessible geological interval to understand climate processes of a warmer world. We show that model-predicted surface air temperatures reveal a substantial cold bias in the Northern Hemisphere. Particularly strong data–model mismatches in mean annual temperatures (up to 18 °C) exist in northern Russia. Our model sensitivity tests identify insufficient temporal constraints hampering the accurate configuration of model boundary conditions as an important factor impacting on data–model discrepancies. We conclude that to allow a more robust evaluation of the ability of present climate models to predict warm climates, future Pliocene data–model comparison studies should focus on orbitally defined time slices.
- Published
- 2013
19. Impact of ocean coupling strategy on extremes in high-resolution atmospheric simulations
- Author
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Zarzycki, C. M., primary, Reed, K. A., additional, Bacmeister, J., additional, Craig, A. P., additional, Bates, S. C., additional, and Rosenbloom, N. A., additional
- Published
- 2015
- Full Text
- View/download PDF
20. Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives
- Author
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Albani, S., primary, Mahowald, N. M., additional, Winckler, G., additional, Anderson, R. F., additional, Bradtmiller, L. I., additional, Delmonte, B., additional, François, R., additional, Goman, M., additional, Heavens, N. G., additional, Hesse, P. P., additional, Hovan, S. A., additional, Kang, S. G., additional, Kohfeld, K. E., additional, Lu, H., additional, Maggi, V., additional, Mason, J. A., additional, Mayewski, P. A., additional, McGee, D., additional, Miao, X., additional, Otto-Bliesner, B. L., additional, Perry, A. T., additional, Pourmand, A., additional, Roberts, H. M., additional, Rosenbloom, N., additional, Stevens, T., additional, and Sun, J., additional
- Published
- 2015
- Full Text
- View/download PDF
21. Impact of the dynamical core on the direct simulation of tropical cyclones in a high‐resolution global model
- Author
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Reed, K. A., primary, Bacmeister, J. T., additional, Rosenbloom, N. A., additional, Wehner, M. F., additional, Bates, S. C., additional, Lauritzen, P. H., additional, Truesdale, J. E., additional, and Hannay, C., additional
- Published
- 2015
- Full Text
- View/download PDF
22. Arctic sea ice in the PlioMIP ensemble: is model performance for modern climates a reliable guide to performance for the past or the future?
- Author
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Howell, F. W., primary, Haywood, A. M., additional, Otto-Bliesner, B. L., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Contoux, C., additional, Kamae, Y., additional, Abe-Ouchi, A., additional, Rosenbloom, N. A., additional, Stepanek, C., additional, and Zhang, Z., additional
- Published
- 2015
- Full Text
- View/download PDF
23. Using results from the PlioMIP ensemble to investigate the Greenland Ice Sheet during the mid-Pliocene Warm Period
- Author
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Dolan, A. M., primary, Hunter, S. J., additional, Hill, D. J., additional, Haywood, A. M., additional, Koenig, S. J., additional, Otto-Bliesner, B. L., additional, Abe-Ouchi, A., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Contoux, C., additional, Jost, A., additional, Kamae, Y., additional, Lohmann, G., additional, Lunt, D. J., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, Stepanek, C., additional, Ueda, H., additional, Yan, Q., additional, and Zhang, Z., additional
- Published
- 2015
- Full Text
- View/download PDF
24. Evaluating the dominant components of warming in Pliocene climate simulations
- Author
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Hill, D. J., Haywood, A. M., Lunt, D. J., Hunter, S. J., Bragg, F. J., Contoux, C., Stepanek, Christian, Sohl, L., Rosenbloom, N. A., Chan, W.-L., Kamae, Y., Zhang, Z., Abe-Ouchi, A., Chandler, M. A., Jost, A., Lohmann, Gerrit, Otto-Bliesner, B. L., Ramstein, G., Ueda, H., Hill, D. J., Haywood, A. M., Lunt, D. J., Hunter, S. J., Bragg, F. J., Contoux, C., Stepanek, Christian, Sohl, L., Rosenbloom, N. A., Chan, W.-L., Kamae, Y., Zhang, Z., Abe-Ouchi, A., Chandler, M. A., Jost, A., Lohmann, Gerrit, Otto-Bliesner, B. L., Ramstein, G., and Ueda, H.
- Abstract
The Pliocene Model Intercomparison Project (PlioMIP) is the first coordinated climate model comparison for a warmer palaeoclimate with atmospheric CO2 significantly higher than pre-industrial concentrations. The simulations of the mid-Pliocene warm period show global warming of between 1.8 and 3.6 °C above pre-industrial surface air temperatures, with significant polar amplification. Here we perform energy balance calculations on all eight of the coupled ocean–atmosphere simulations within PlioMIP Experiment 2 to evaluate the causes of the increased temperatures and differences between the models. In the tropics simulated warming is dominated by greenhouse gas increases, with the cloud component of planetary albedo enhancing the warming in most of the models, but by widely varying amounts. The responses to mid-Pliocene climate forcing in the Northern Hemisphere midlatitudes are substantially different between the climate models, with the only consistent response being a warming due to increased greenhouse gases. In the high latitudes all the energy balance components become important, but the dominant warming influence comes from the clear sky albedo, only partially offset by the increases in the cooling impact of cloud albedo. This demonstrates the importance of specified ice sheet and high latitude vegetation boundary conditions and simulated sea ice and snow albedo feedbacks. The largest components in the overall uncertainty are associated with clouds in the tropics and polar clear sky albedo, particularly in sea ice regions. These simulations show that albedo feedbacks, particularly those of sea ice and ice sheets, provide the most significant enhancements to high latitude warming in the Pliocene.
- Published
- 2014
25. Supplementary material to "Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives"
- Author
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Albani, S., primary, Mahowald, N. M., additional, Winckler, G., additional, Anderson, R. F., additional, Bradtmiller, L. I., additional, Delmonte, B., additional, François, R., additional, Goman, M., additional, Heavens, N. G., additional, Hesse, P. P., additional, Hovan, S. A., additional, Kohfeld, K. E., additional, Lu, H., additional, Maggi, V., additional, Mason, J. A., additional, Mayewski, P. A., additional, McGee, D., additional, Miao, X., additional, Otto-Bliesner, B. L., additional, Perry, A. T., additional, Pourmand, A., additional, Roberts, H. M., additional, Rosenbloom, N., additional, Stevens, T., additional, and Sun, J., additional
- Published
- 2014
- Full Text
- View/download PDF
26. Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives
- Author
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Albani, S., primary, Mahowald, N. M., additional, Winckler, G., additional, Anderson, R. F., additional, Bradtmiller, L. I., additional, Delmonte, B., additional, François, R., additional, Goman, M., additional, Heavens, N. G., additional, Hesse, P. P., additional, Hovan, S. A., additional, Kohfeld, K. E., additional, Lu, H., additional, Maggi, V., additional, Mason, J. A., additional, Mayewski, P. A., additional, McGee, D., additional, Miao, X., additional, Otto-Bliesner, B. L., additional, Perry, A. T., additional, Pourmand, A., additional, Roberts, H. M., additional, Rosenbloom, N., additional, Stevens, T., additional, and Sun, J., additional
- Published
- 2014
- Full Text
- View/download PDF
27. Using results from the PlioMIP ensemble to investigate the Greenland Ice Sheet during the warm Pliocene
- Author
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Dolan, A. M., primary, Hunter, S. J., additional, Hill, D. J., additional, Haywood, A. M., additional, Koenig, S. J., additional, Otto-Bliesner, B. L., additional, Abe-Ouchi, A., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Contoux, C., additional, Jost, A., additional, Kamae, Y., additional, Lohmann, G., additional, Lunt, D. J., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, Stepanek, C., additional, Ueda, H., additional, Yan, Q., additional, and Zhang, Z., additional
- Published
- 2014
- Full Text
- View/download PDF
28. A multi-model assessment of last interglacial temperatures
- Author
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UCL - SST/ELI/ELIC - Earth & Climate, Lunt, D.J., Abe-Ouchi, Ayako, Bakker, P., Berger, Andre, Braconnot, P., Charbit, S., Fischer, N., Herold, Nicholas, Jungclaus, J.H., Khon, V.C., Krebs-Kanzow, U., Langebroek, P.M., Lohmann, G., Nisancioglu, K.H., Otto-Bliesner, B.L., Park, W., Pfeiffer, M., Phipps, S.J., Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, B., Stone, E.J., Takahashi, K., Wei, W., Yin, Qiuzhen, Zhang, Z.S., UCL - SST/ELI/ELIC - Earth & Climate, Lunt, D.J., Abe-Ouchi, Ayako, Bakker, P., Berger, Andre, Braconnot, P., Charbit, S., Fischer, N., Herold, Nicholas, Jungclaus, J.H., Khon, V.C., Krebs-Kanzow, U., Langebroek, P.M., Lohmann, G., Nisancioglu, K.H., Otto-Bliesner, B.L., Park, W., Pfeiffer, M., Phipps, S.J., Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, B., Stone, E.J., Takahashi, K., Wei, W., Yin, Qiuzhen, and Zhang, Z.S.
- Abstract
The last interglaciation (130 to 116 ka) is a time period with a strong astronomically induced seasonal forcing of insolation compared to the present. Proxy records indicate a significantly different climate to that of the modern, in particular Arctic summer warming and higher eustatic sea level. Because the forcings are relatively well constrained, it provides an opportunity to test numerical models which are used for future climate prediction. In this paper we compile a set of climate model simulations of the early last interglaciation (130 to 125 ka), encompassing a range of model complexities. We compare the simulations to each other and to a recently published compilation of last interglacial temperature estimates.We show that the annual mean response of the models is rather small, with no clear signal in many regions. However, the seasonal response is more robust, and there is significant agreement amongst models as to the regions of warming vs cooling. However, the quantitative agreement of the model simulations with data is poor, with the models in general underestimating the magnitude of response seen in the proxies. Taking possible seasonal biases in the proxies into account improves the agreement, but only marginally. However, a lack of uncertainty estimates in the data does not allow us to draw firm conclusions. Instead, this paper points to several ways in which both modelling and data could be improved, to allow a more robust model–data comparison.
- Published
- 2013
29. Challenges in quantifying Pliocene terrestrial warming revealed by data–model discord
- Author
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Salzmann, U., Dolan, A. M., Haywood, A. M., Chan, W.-L., Voss, J., Hill, D. J., Abe-Ouchi, A., Otto-Bliesner, B., Bragg, F. J., Chandler, M. A., Contoux, C., Dowsett, H. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Pickering, S. J., Pound, M. J., Ramstein, G., Rosenbloom, N. A., Sohl, L., Stepanek, Christian, Ueda, H., Zhang, Z., Salzmann, U., Dolan, A. M., Haywood, A. M., Chan, W.-L., Voss, J., Hill, D. J., Abe-Ouchi, A., Otto-Bliesner, B., Bragg, F. J., Chandler, M. A., Contoux, C., Dowsett, H. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Pickering, S. J., Pound, M. J., Ramstein, G., Rosenbloom, N. A., Sohl, L., Stepanek, Christian, Ueda, H., and Zhang, Z.
- Abstract
Comparing simulations of key warm periods in Earth history with contemporaneous geological proxy data is a useful approach for evaluating the ability of climate models to simulate warm, high-CO2 climates that are unprecedented in the more recent past. Here we use a global data set of confidence-assessed, proxy-based temperature estimates and biome reconstructions to assess the ability of eight models to simulate warm terrestrial climates of the Pliocene epoch. The Late Pliocene, 3.6–2.6 million years ago, is an accessible geological interval to understand climate processes of a warmer world. We show that model-predicted surface air temperatures reveal a substantial cold bias in the Northern Hemisphere. Particularly strong data–model mismatches in mean annual temperatures (up to 18 °C) exist in northern Russia. Our model sensitivity tests identify insufficient temporal constraints hampering the accurate configuration of model boundary conditions as an important factor impacting on data–model discrepancies. We conclude that to allow a more robust evaluation of the ability of present climate models to predict warm climates, future Pliocene data–model comparison studies should focus on orbitally defined time slices.
- Published
- 2013
30. Mid-Pliocene East Asian monsoon climate simulated in the PlioMIP
- Author
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Zhang, R., Yan, Q., Zhang, Z. S., Jiang, D., Otto-Bliesner, B. L., Haywood, A. M., Hill, D. J., Dolan, A. M., Stepanek, Christian, Lohmann, Gerrit, Contoux, C., Bragg, F., Chan, W.-L., Chandler, M. A., Jost, A., Kamae, Y., Abe-Ouchi, A., Ramstein, G., Rosenbloom, N. A., Sohl, L., Ueda, H., Zhang, R., Yan, Q., Zhang, Z. S., Jiang, D., Otto-Bliesner, B. L., Haywood, A. M., Hill, D. J., Dolan, A. M., Stepanek, Christian, Lohmann, Gerrit, Contoux, C., Bragg, F., Chan, W.-L., Chandler, M. A., Jost, A., Kamae, Y., Abe-Ouchi, A., Ramstein, G., Rosenbloom, N. A., Sohl, L., and Ueda, H.
- Abstract
Based on simulations with 15 climate models in the Pliocene Model Intercomparison Project (PlioMIP), the regional climate of East Asia (focusing on China) during the mid-Pliocene is investigated in this study. Compared to the pre-industrial, the multi-model ensemble mean (MMM) of all models shows the East Asian summer winds (EASWs) largely strengthen in monsoon China, and the East Asian winter winds (EAWWs) strengthen in south monsoon China but slightly weaken in north monsoon China in the mid-Pliocene. The MMM of all models also illustrates a warmer and wetter mid-Pliocene climate in China. The simulated weakened mid-Pliocene EAWWs in north monsoon China and intensified EASWs in monsoon China agree well with geological reconstructions. However, there is a large model–model discrepancy in simulating mid-Pliocene EAWW, which should be further addressed in the future work of PlioMIP.
- Published
- 2013
31. Mid-pliocene Atlantic Meridional Overturning Circulation not unlike modern
- Author
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Zhang, Z.-S., Nisancioglu, K. H., Chandler, M. A., Haywood, A. M., Otto-Bliesner, B. L., Ramstein, G., Stepanek, Christian, Abe-Ouchi, A., Chan, W.-L., Bragg, F. J., Contoux, C., Dolan, A. M., Hill, D. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Rosenbloom, N. A., Sohl, L. E., Ueda, H., Zhang, Z.-S., Nisancioglu, K. H., Chandler, M. A., Haywood, A. M., Otto-Bliesner, B. L., Ramstein, G., Stepanek, Christian, Abe-Ouchi, A., Chan, W.-L., Bragg, F. J., Contoux, C., Dolan, A. M., Hill, D. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Rosenbloom, N. A., Sohl, L. E., and Ueda, H.
- Abstract
In the Pliocene Model Intercomparison Project (PlioMIP), eight state-of-the-art coupled climate models have simulated the mid-Pliocene warm period (mPWP, 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), northward ocean heat transport and ocean stratification simulated with these models. None of the models participating in PlioMIP simulates a strong mid-Pliocene AMOC as suggested by earlier proxy studies. Rather, there is no consistent increase in AMOC maximum among the PlioMIP models. The only consistent change in AMOC is a shoaling of the overturning cell in the Atlantic, and a reduced influence of North Atlantic DeepWater (NADW) at depth in the basin. Furthermore, the simulated mid-Pliocene Atlantic northward heat transport is similar to the pre-industrial. These simulations demonstrate that the reconstructed high-latitude mid-Pliocene warming can not be explained as a direct response to an intensification of AMOC and concomitant increase in northward ocean heat transport by the Atlantic.
- Published
- 2013
32. Sea Surface Temperature of the mid-Piacenzian Ocean: A Data-Model Comparison
- Author
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Dowsett, H. J., Foley, K. M., Stoll, D. K., Chandler, M. A., Sohl, L. E., Bentsen, M., Otto-Bliesner, B. L., Bragg, F. J., Chan, W-L., Contoux, C., Dolan, A. M., Haywood, A. M., Jonas, J. A., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Nisancioglu, K. H., Abe-Ouchi, A., Ramstein, G., Riesselman, C., Robinson, M. M., Rosenbloom, N. A., Salzmann, U., Stepanek, Christian, Strother, S. L., Ueda, H., Yan, Q., Zhang, Z., Dowsett, H. J., Foley, K. M., Stoll, D. K., Chandler, M. A., Sohl, L. E., Bentsen, M., Otto-Bliesner, B. L., Bragg, F. J., Chan, W-L., Contoux, C., Dolan, A. M., Haywood, A. M., Jonas, J. A., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Nisancioglu, K. H., Abe-Ouchi, A., Ramstein, G., Riesselman, C., Robinson, M. M., Rosenbloom, N. A., Salzmann, U., Stepanek, Christian, Strother, S. L., Ueda, H., Yan, Q., and Zhang, Z.
- Abstract
The mid-Piacenzian climate represents the most geologically recent interval of long-term average warmth relative to the last million years, and shares similarities with the climate projected for the end of the 21st century. As such, it represents a natural experiment from which we can gain insight into potential climate change impacts, enabling more informed policy decisions for mitigation and adaptation. Here, we present the first systematic comparison of Pliocene sea surface temperature (SST) between an ensemble of eight climate model simulations produced as part of PlioMIP (Pliocene Model Intercomparison Project) with the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) Project mean annual SST field. Our results highlight key regional and dynamic situations where there is discord between the palaeoenvironmental reconstruction and the climate model simulations. These differences have led to improved strategies for both experimental design and temporal refinement of the palaeoenvironmental reconstruction.
- Published
- 2013
33. A multi-model assessment of last interglacial temperatures
- Author
-
Lunt, D.J., Abe-Ouchi, A., Bakker, P., Berger, A., Braconnot, P., Charbit, S., Fischer, N., Herold, N, Jungclaus, J.H., Kohn, V.C, Krebs-Kanzow, Uta, Lohmann, Gerrit, Otto-Bliesner, B., Park, W., Pfeiffer, Madlene, Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, B., Stone, E.J., Takahashi, K., Wei, Wei, Yin, Q., Lunt, D.J., Abe-Ouchi, A., Bakker, P., Berger, A., Braconnot, P., Charbit, S., Fischer, N., Herold, N, Jungclaus, J.H., Kohn, V.C, Krebs-Kanzow, Uta, Lohmann, Gerrit, Otto-Bliesner, B., Park, W., Pfeiffer, Madlene, Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, B., Stone, E.J., Takahashi, K., Wei, Wei, and Yin, Q.
- Abstract
The last interglaciation (~130 to 116 ka) is a time period with a strong astronomically induced seasonal forcing of insolation compared to the present. Proxy records indicate a significantly different climate to that of the modern, in particular Arctic summer warming and higher eustatic sea level. Because the forcings are relatively well constrained, it provides an opportunity to test numerical models which are used for future climate prediction. In this paper we compile a set of climate model simulations of the early last interglaciation (130 to 125 ka), encompassing a range of model complexities. We compare the simulations to each other and to a recently published compilation of last interglacial temperature estimates. We show that the annual mean response of the models is rather small, with no clear signal in many regions. However, the seasonal response is more robust, and there is significant agreement amongst models as to the regions of warming vs cooling. However, the quantitative agreement of the model simulations with data is poor, with the models in general underestimating the magnitude of response seen in the proxies. Taking possible seasonal biases in the proxies into account improves the agreement, but only marginally. However, a lack of uncertainty estimates in the data does not allow us to draw firm conclusions. Instead, this paper points to several ways in which both modelling and data could be improved, to allow a more robust model–data comparison.
- Published
- 2013
34. Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project
- Author
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Haywood, A. M., Hill, D. J., Dolan, A. M., Otto-Bliesner, B. L., Bragg, F., Chan, W.-L., Chandler, M. A., Contoux, C., Dowsett, H. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Abe-Ouchi, A., Pickering, S. J., Ramstein, G., Rosenbloom, N. A., Salzmann, U., Sohl, L., Stepanek, Christian, Ueda, H., Yan, Q., Zhang, Z., Haywood, A. M., Hill, D. J., Dolan, A. M., Otto-Bliesner, B. L., Bragg, F., Chan, W.-L., Chandler, M. A., Contoux, C., Dowsett, H. J., Jost, A., Kamae, Y., Lohmann, Gerrit, Lunt, D. J., Abe-Ouchi, A., Pickering, S. J., Ramstein, G., Rosenbloom, N. A., Salzmann, U., Sohl, L., Stepanek, Christian, Ueda, H., Yan, Q., and Zhang, Z.
- Abstract
Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied. Whilst numerical models have shed light on the nature of climate at the time, uncertainties in their predictions have not been systematically examined. The Pliocene Model Intercomparison Project quantifies uncertainties in model outputs through a coordinated multi-model and multi-model/data intercomparison. Whilst commonalities in model outputs for the Pliocene are clearly evident, we show substantial variation in the sensitivity of models to the implementation of Pliocene boundary conditions. Models appear able to reproduce many regional changes in temperature reconstructed from geological proxies. However, data/model comparison highlights that models potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations in the time-averaged proxy data currently available must be addressed. Furthermore, sensitivity tests exploring the known unknowns in modelling Pliocene climate specifically relevant to the high latitudes are essential (e.g. palaeogeography, gateways, orbital forcing and trace gasses). Estimates of longer-term sensitivity to CO2 (also known as Earth System Sensitivity; ESS), support previous work suggesting that ESS is greater than Climate Sensitivity (CS), and suggest that the ratio of ESS to CS is between 1 and 2, with a "best" estimate of 1.5.
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- 2013
35. A multi-model assessment of last interglacial temperatures
- Author
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Lunt, D. J., Abe-Ouchi, A., Bakker, P., Berger, A., Braconnot, P., Charbit, S., Fischer, N., Herold, N., Jungclaus, J. H., Khon, V. C., Krebs-Kanzow, U., Langebroek, P. M., Lohmann, G., Nisancioglu, K. H., Otto-Bliesner, B. L., Park, Wonsun, Pfeiffer, M., Phipps, S. J., Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, Birgit, Stone, E. J., Takahashi, K., Wei, W., Yin, Q., Zhang, Z. S., Lunt, D. J., Abe-Ouchi, A., Bakker, P., Berger, A., Braconnot, P., Charbit, S., Fischer, N., Herold, N., Jungclaus, J. H., Khon, V. C., Krebs-Kanzow, U., Langebroek, P. M., Lohmann, G., Nisancioglu, K. H., Otto-Bliesner, B. L., Park, Wonsun, Pfeiffer, M., Phipps, S. J., Prange, M., Rachmayani, R., Renssen, H., Rosenbloom, N., Schneider, Birgit, Stone, E. J., Takahashi, K., Wei, W., Yin, Q., and Zhang, Z. S.
- Abstract
The last interglaciation (~130 to 116 ka) is a time period with a strong astronomically induced seasonal forcing of insolation compared to the present. Proxy records indicate a significantly different climate to that of the modern, in particular Arctic summer warming and higher eustatic sea level. Because the forcings are relatively well constrained, it provides an opportunity to test numerical models which are used for future climate prediction. In this paper we compile a set of climate model simulations of the early last interglaciation (130 to 125 ka), encompassing a range of model complexities. We compare the simulations to each other and to a recently published compilation of last interglacial temperature estimates. We show that the annual mean response of the models is rather small, with no clear signal in many regions. However, the seasonal response is more robust, and there is significant agreement amongst models as to the regions of warming vs cooling. However, the quantitative agreement of the model simulations with data is poor, with the models in general underestimating the magnitude of response seen in the proxies. Taking possible seasonal biases in the proxies into account improves the agreement, but only marginally. However, a lack of uncertainty estimates in the data does not allow us to draw firm conclusions. Instead, this paper points to several ways in which both modelling and data could be improved, to allow a more robust model–data comparison.
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- 2013
- Full Text
- View/download PDF
36. The amplification of Arctic terrestrial surface temperatures by reduced sea-ice extentduring the Pliocene
- Author
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Ballantyne, A., Axford, Y., Miller, Gifford, Otto-Bliesner, B., Rosenbloom, N., white, J., Ballantyne, A., Axford, Y., Miller, Gifford, Otto-Bliesner, B., Rosenbloom, N., and white, J.
- Abstract
Many past warm periods exhibited greatly reduced latitudinal temperature gradients as a result of amplified Arctic surface temperatures as well as more seasonably equable temperatures. The Pliocene is a period of particular interest because CO2 forcing was comparable to today and yet Arctic temperatures were significantly warmer than today. Here we describe an atmospheric general circulation model experiment assessing the response of terrestrial temperatures in the mid-Pliocene (3.02 to 3.26 Ma) to an ice-free Arctic, and we compare the simulation with a compilation of proxy-based Pliocene paleotemperature reconstructions. Our experiments indicate that the amplification of Arctic surface temperatures is much more sensitive to the extent of sea ice than continental ice. The removal of Arctic sea ice results in simulated mean annual surface temperatures that better match terrestrial proxy data (RMSE = 2.9 °C) than experimental conditions that included seasonal sea ice (RMSE = 4.5 °C). Our simulations also show a decrease in the seasonal amplitude of temperatures in the absence of sea-ice, which is consistent with theory predicting more equable climates in the Arctic during warmer intervals in Earth's history. Our results demonstrate that once sea-ice is removed, latent heat is lost from the ocean to the atmosphere as water vapor that can be circulated by the atmosphere,which results in warming of continental interiors. Although our sensitivity experiment does not help to identify the full array of feedback mechanisms responsible for the amplification of Arctic surface temperatures during the Pliocene, it does demonstrate that Arctic terrestrial surface temperatures are extremely sensitive to the spatial and seasonal extent of sea-ice.
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- 2013
37. Pliocene Model Intercomparison Project (PlioMIP) : experimental design and boundary conditions (Experiment 1)
- Author
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Haywood, A.M., Dowsett, H.J., Otto-Bliesner, B., Chandler, M.A., Dolan, A.M., Hill, D.J., Lunt, D.J., Robinson, M.M., Rosenbloom, N., Salzmann, U., Sohl, L.E., Haywood, A.M., Dowsett, H.J., Otto-Bliesner, B., Chandler, M.A., Dolan, A.M., Hill, D.J., Lunt, D.J., Robinson, M.M., Rosenbloom, N., Salzmann, U., and Sohl, L.E.
- Abstract
In 2008 the temporal focus of the Palaeoclimate Modelling Intercomparison Project was expanded to include a model intercomparison for the mid-Pliocene warm period (3.29–2.97 million years ago). This project is referred to as PlioMIP (Pliocene Model Intercomparison Project). Two experiments have been agreed upon and comprise phase 1 of PlioMIP. The first (Experiment 1) will be performed with atmosphere-only climate models. The second (Experiment 2) will utilise fully coupled ocean-atmosphere climate models. The aim of this paper is to provide a detailed model intercomparison project description which documents the experimental design in a more detailed way than has previously been done in the literature. Specifically, this paper describes the experimental design and boundary conditions that will be utilised for Experiment 1 of PlioMIP.
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- 2010
38. Mid-Pliocene East Asian monsoon climate simulated in the PlioMIP
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Zhang, R., primary, Yan, Q., additional, Zhang, Z. S., additional, Jiang, D., additional, Otto-Bliesner, B. L., additional, Haywood, A. M., additional, Hill, D. J., additional, Dolan, A. M., additional, Stepanek, C., additional, Lohmann, G., additional, Contoux, C., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Jost, A., additional, Kamae, Y., additional, Abe-Ouchi, A., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, and Ueda, H., additional
- Published
- 2013
- Full Text
- View/download PDF
39. Mid-pliocene Atlantic Meridional Overturning Circulation not unlike modern
- Author
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Zhang, Z.-S., primary, Nisancioglu, K. H., additional, Chandler, M. A., additional, Haywood, A. M., additional, Otto-Bliesner, B. L., additional, Ramstein, G., additional, Stepanek, C., additional, Abe-Ouchi, A., additional, Chan, W.-L., additional, Bragg, F. J., additional, Contoux, C., additional, Dolan, A. M., additional, Hill, D. J., additional, Jost, A., additional, Kamae, Y., additional, Lohmann, G., additional, Lunt, D. J., additional, Rosenbloom, N. A., additional, Sohl, L. E., additional, and Ueda, H., additional
- Published
- 2013
- Full Text
- View/download PDF
40. Reforming Hollywood: How American Protestants Fought for Freedom at the Movies
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Rosenbloom, N. J., primary
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- 2013
- Full Text
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41. Simulating the mid-Pliocene Warm Period with the CCSM4 model
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Rosenbloom, N. A., primary, Otto-Bliesner, B. L., additional, Brady, E. C., additional, and Lawrence, P. J., additional
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- 2013
- Full Text
- View/download PDF
42. Evaluating the dominant components of warming in Pliocene climate simulations
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Hill, D. J., primary, Haywood, A. M., additional, Lunt, D. J., additional, Hunter, S. J., additional, Bragg, F. J., additional, Contoux, C., additional, Stepanek, C., additional, Sohl, L., additional, Rosenbloom, N. A., additional, Chan, W-L., additional, Kamae, Y., additional, Zhang, Z., additional, Abe-Ouchi, A., additional, Chandler, M. A., additional, Jost, A., additional, Lohmann, G., additional, Otto-Bliesner, B. L., additional, Ramstein, G., additional, and Ueda, H., additional
- Published
- 2013
- Full Text
- View/download PDF
43. A multi-model assessment of last interglacial temperatures
- Author
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Lunt, D. J., primary, Abe-Ouchi, A., additional, Bakker, P., additional, Berger, A., additional, Braconnot, P., additional, Charbit, S., additional, Fischer, N., additional, Herold, N., additional, Jungclaus, J. H., additional, Khon, V. C., additional, Krebs-Kanzow, U., additional, Langebroek, P. M., additional, Lohmann, G., additional, Nisancioglu, K. H., additional, Otto-Bliesner, B. L., additional, Park, W., additional, Pfeiffer, M., additional, Phipps, S. J., additional, Prange, M., additional, Rachmayani, R., additional, Renssen, H., additional, Rosenbloom, N., additional, Schneider, B., additional, Stone, E. J., additional, Takahashi, K., additional, Wei, W., additional, Yin, Q., additional, and Zhang, Z. S., additional
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- 2013
- Full Text
- View/download PDF
44. Supplementary material to "East Asian monsoon climate simulated in the PlioMIP"
- Author
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Zhang, R., primary, Yan, Q., additional, Zhang, Z. S., additional, Jiang, D., additional, Otto-Bliesner, B. L., additional, Haywood, A. M., additional, Hill, D. J., additional, Dolan, A. M., additional, Stepanek, C., additional, Lohmann, G., additional, Contoux, C., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Jost, A., additional, Kamae, Y., additional, Abe-Ouchi, A., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, and Ueda, H., additional
- Published
- 2013
- Full Text
- View/download PDF
45. East Asian monsoon climate simulated in the PlioMIP
- Author
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Zhang, R., primary, Yan, Q., additional, Zhang, Z. S., additional, Jiang, D., additional, Otto-Bliesner, B. L., additional, Haywood, A. M., additional, Hill, D. J., additional, Dolan, A. M., additional, Stepanek, C., additional, Lohmann, G., additional, Contoux, C., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Jost, A., additional, Kamae, Y., additional, Abe-Ouchi, A., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, and Ueda, H., additional
- Published
- 2013
- Full Text
- View/download PDF
46. Simulating the mid-Pliocene Warm Period with the CCSM4 model
- Author
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Rosenbloom, N. A., primary, Otto-Bliesner, B. L., additional, Brady, E. C., additional, and Lawrence, P. J., additional
- Published
- 2012
- Full Text
- View/download PDF
47. A multi-model assessment of last interglacial temperatures
- Author
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Lunt, D. J., primary, Abe-Ouchi, A., additional, Bakker, P., additional, Berger, A., additional, Braconnot, P., additional, Charbit, S., additional, Fischer, N., additional, Herold, N., additional, Jungclaus, J. H., additional, Khon, V. C., additional, Krebs-Kanzow, U., additional, Lohmann, G., additional, Otto-Bliesner, B., additional, Park, W., additional, Pfeiffer, M., additional, Prange, M., additional, Rachmayani, R., additional, Renssen, H., additional, Rosenbloom, N., additional, Schneider, B., additional, Stone, E. J., additional, Takahashi, K., additional, Wei, W., additional, and Yin, Q., additional
- Published
- 2012
- Full Text
- View/download PDF
48. Supplementary material to "Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project"
- Author
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Haywood, A. M., primary, Hill, D. J., additional, Dolan, A. M., additional, Otto-Bliesner, B., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Contoux, C., additional, Jost, A., additional, Kamae, Y., additional, Lohmann, G., additional, Lunt, D. J., additional, Abe-Ouchi, A., additional, Pickering, S. J., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, Stepanek, C., additional, Yan, Q., additional, Ueda, H., additional, and Zhang, Z., additional
- Published
- 2012
- Full Text
- View/download PDF
49. Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project
- Author
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Haywood, A. M., primary, Hill, D. J., additional, Dolan, A. M., additional, Otto-Bliesner, B., additional, Bragg, F., additional, Chan, W.-L., additional, Chandler, M. A., additional, Contoux, C., additional, Jost, A., additional, Kamae, Y., additional, Lohmann, G., additional, Lunt, D. J., additional, Abe-Ouchi, A., additional, Pickering, S. J., additional, Ramstein, G., additional, Rosenbloom, N. A., additional, Sohl, L., additional, Stepanek, C., additional, Yan, Q., additional, Ueda, H., additional, and Zhang, Z., additional
- Published
- 2012
- Full Text
- View/download PDF
50. Vegetation-climate interactions in the warm mid-Cretaceous
- Author
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Zhou, J., primary, Poulsen, C. J., additional, Rosenbloom, N., additional, Shields, C., additional, and Briegleb, B., additional
- Published
- 2012
- Full Text
- View/download PDF
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