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Mid-Pliocene West African Monsoon Rainfall as simulated in the PlioMIP2 ensemble Clim. Past (IF 3.536) Pub Date : 2021-02-26 Ellen Berntell; Qiong Zhang; Qiang Li; Alan M. Haywood; Julia C. Tindall; Stephen J. Hunter; Zhongshi Zhang; Xiangyu Li; Chuncheng Guo; Kerim H. Nisancioglu; Christian Stepanek; Gerrit Lohmann; Linda E. Sohl; Mark A. Chandler; Ning Tan; Camille Contoux; Gilles Ramstein; Michiel L. J. Baatsen; Anna S. von der Heydt; Deepak Chandan; William Richard Peltier; Ayako Abe-Ouchi; Wing-Le Chan; Youichi Kamae;
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 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
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Eddy permitting simulations of freshwater injection from major Northern Hemisphere outlets during the last deglacial Clim. Past (IF 3.536) Pub Date : 2021-02-26 Ryan Love; Heather Andres; Alan Condron; Lev Tarasov
Abstract. Freshwater, in the form of glacial runoff, is hypothesized to play a critical role in centennial to millennial scale climate variability such as the Younger Dryas and Dansgaard-Oeschger Events. Indeed, freshwater injection/hosing experiments with climate models have long shown that freshwater has the capability of generating such abrupt climate transitions. However, the relationship between
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Mid-Pliocene Atlantic Meridional Overturning Circulation simulated in PlioMIP2 Clim. Past (IF 3.536) Pub Date : 2021-02-25 Zhongshi Zhang; Xiangyu Li; Chuncheng Guo; Odd Helge Otterå; Kerim H. Nisancioglu; Ning Tan; Camille Contoux; Gilles Ramstein; Ran Feng; Bette L. Otto-Bliesner; Esther Brady; Deepak Chandan; W. Richard Peltier; Michiel L. J. Baatsen; Anna S. von der Heydt; Julia E. Weiffenbach; Christian Stepanek; Gerrit Lohmann; Qiong Zhang; Qiang Li; Mark A. Chandler; Linda E. Sohl; Alan M. Haywood; Stephen J. Hunter;
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
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Lower oceanic δ13C during the last interglacial period compared to the Holocene Clim. Past (IF 3.536) Pub Date : 2021-02-25 Shannon A. Bengtson; Laurie C. Menviel; Katrin J. Meissner; Lise Missiaen; Carlye D. Peterson; Lorraine E. Lisiecki; Fortunat Joos
Abstract. The last time in Earth's history when high latitudes were warmer than during pre-industrial times was the last interglacial period (LIG, 129–116 ka BP). Since the LIG is the most recent and best documented interglacial, it can provide insights into climate processes in a warmer world. However, some key features of the LIG are not well constrained, notably the oceanic circulation and the global
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Atmospheric iron supply and marine productivity in the glacial North Pacific Ocean Clim. Past (IF 3.536) Pub Date : 2021-02-23 François Burgay; Andrea Spolaor; Jacopo Gabrieli; Giulio Cozzi; Clara Turetta; Paul Vallelonga; Carlo Barbante
Iron (Fe) is a key element in the Earth climate system, as it can enhance marine primary productivity in the high-nutrient low-chlorophyll (HNLC) regions where, despite a high concentration of major nutrients, chlorophyll production is low due to iron limitation. Eolian mineral dust represents one of the main Fe sources to the oceans; thus, quantifying its variability over the last glacial cycle is
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A pseudoproxy assessment of why climate field reconstruction methods perform the way they do in time and space Clim. Past (IF 3.536) Pub Date : 2021-02-23 Sooin Yun; Jason E. Smerdon; Bo Li; Xianyang Zhang
Abstract. Spatiotemporal paleoclimate reconstructions that seek to estimate climate conditions over the last several millennia are derived from multiple climate proxy records (e.g. tree rings, ice cores, corals, and cave formations) that are heterogeneously distributed across land and marine environments. Assessing the skill of the methods used for these reconstructions is critical as a means of understanding
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Driving mechanisms of organic carbon burial in the Early Cretaceous South Atlantic Cape Basin (DSDP Site 361) Clim. Past (IF 3.536) Pub Date : 2021-02-19 Wolf Dummann; Sebastian Steinig; Peter Hofmann; Matthias Lenz; Stephanie Kusch; Sascha Flögel; Jens Olaf Herrle; Christian Hallmann; Janet Rethemeyer; Haino Uwe Kasper; Thomas Wagner
Extensive black shale deposits formed in the Early Cretaceous South Atlantic, supporting the notion that this emerging ocean basin was a globally important site of organic carbon burial. The magnitude of organic carbon burial in marine basins is known to be controlled by various tectonic, oceanographic, hydrological, and climatic processes acting on different temporal and spatial scales, the nature
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Long-term global ground heat flux and continental heat storage from geothermal data Clim. Past (IF 3.536) Pub Date : 2021-02-19 Francisco José Cuesta-Valero; Almudena García-García; Hugo Beltrami; J. Fidel González-Rouco; Elena García-Bustamante
Energy exchanges among climate subsystems are of critical importance to determine the climate sensitivity of the Earth's system to greenhouse gases, to quantify the magnitude and evolution of the Earth's energy imbalance, and to project the evolution of future climate. Thus, ascertaining the magnitude of and change in the Earth's energy partition within climate subsystems has become urgent in recent
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531-year non-growth season precipitation reconstruction in the southeastern Tibetan Plateau Clim. Past (IF 3.536) Pub Date : 2021-02-18 Maierdang Keyimu; Zongshan Li; Bojie Fu; Guohua Liu; Weiliang Chen; Zexin Fan; Keyan Fang; Xiuchen Wu; Xiaochun Wang
Abstract. Trees record climatic conditions during their growth, and tree-rings serve as a proxy to reveal the features of the historical climate of a region. In this study, we collected tree-ring cores of forest hemlock (Tsuga forrestii) from the northwestern Yunnan area of the southeastern Tibetan Plateau (SETP), and created a residual tree-ring width (TRW) chronology. An analysis of the relationship
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In situ cosmogenic 10Be–14C–26Al measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size Clim. Past (IF 3.536) Pub Date : 2021-02-17 Nicolás E. Young; Alia J. Lesnek; Josh K. Cuzzone; Jason P. Briner; Jessica A. Badgeley; Alexandra Balter-Kennedy; Brandon L. Graham; Allison Cluett; Jennifer L. Lamp; Roseanne Schwartz; Thibaut Tuna; Edouard Bard; Marc W. Caffee; Susan R. H. Zimmerman; Joerg M. Schaefer
Sometime during the middle to late Holocene (8.2 ka to ∼ 1850–1900 CE), the Greenland Ice Sheet (GrIS) was smaller than its current configuration. Determining the exact dimensions of the Holocene ice-sheet minimum and the duration that the ice margin rested inboard of its current position remains challenging. Contemporary retreat of the GrIS from its historical maximum extent in southwestern Greenland
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Mid-Holocene monsoons in South and Southeast Asia: dynamically downscaled simulations and the influence of the Green Sahara Clim. Past (IF 3.536) Pub Date : 2021-02-17 Yiling Huo; William Richard Peltier; Deepak Chandan
Abstract. Proxy records suggest that the Northern Hemisphere during the mid-Holocene (MH), to be assumed herein to correspond to 6,000 years ago, was generally warmer than today during summer and colder in the winter due to the enhanced seasonal contrast in the amount of solar radiation reaching the top of the atmosphere. The complex orography of both India and Southeast Asia (SEA), which includes
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A Modified Milankovitch theory that reconciles contradictions with the paleoclimate record Clim. Past (IF 3.536) Pub Date : 2021-02-16 Robert E. Wong
Abstract. Based upon research results over the past five decades, there has been a general acceptance that the ice ages were initiated by astronomical phenomenon. Specifically, marine, ice and terrestrial paleoclimate data have supported elements of the Milankovitch astronomical theory of the ice ages. However, there remain unresolved problems between the empirical findings and theory. The 100 thousand
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Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling Clim. Past (IF 3.536) Pub Date : 2021-02-15 Taimaz Bahadory; Lev Tarasov; Heather Andres
We present an ensemble of last glacial inception (LGI) simulations for the Northern Hemisphere that captures a significant fraction of inferred ice volume changes within proxy uncertainties. This ensemble was performed with LCice 1.0, a coupled ice sheet and climate model, varying parameters of both climate and ice sheet components, as well as the coupling between them. Certain characteristics of the
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Enhanced Moisture Delivery into Victoria Land, East Antarctica During the Early Last Interglacial: Implications for West Antarctic Ice Sheet Stability Clim. Past (IF 3.536) Pub Date : 2021-02-10 Yuzhen Yan; Nicole E. Spaulding; Michael L. Bender; Edward J. Brook; John A. Higgins; Andrei V. Kurbatov; Paul A. Mayewski
Abstract. The S27 ice core, drilled in the Allan Hills Blue Ice Area of East Antarctica, is located in Southern Victoria Land ~80 km away from the present-day northern edge of the Ross Ice Shelf. Here, we utilize the reconstructed accumulation rate of S27 covering the Last Interglacial (LIG) period between 129 and 116 thousand years before present (ka) to infer moisture transport into the region. The
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Monitoring landcover change and desertification processes in northern China and Mongolia using historical written sources and vegetation indices Clim. Past (IF 3.536) Pub Date : 2021-02-09 Michael Kempf
Abstract. Fighting land degradation of semi-arid and climate-sensitive grasslands are among the most urgent tasks of current eco-political agenda. Northern China and Mongolia are particularly prone to surface transformations caused by heavily increased livestock numbers during the 20th century. Extensive overgrazing and resource exploitation amplify regional climate change effects and trigger intensified
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Response of biological productivity to North Atlantic marine front migration during the Holocene Clim. Past (IF 3.536) Pub Date : 2021-02-08 David J. Harning; Anne E. Jennings; Denizcan Köseoğlu; Simon T. Belt; Áslaug Geirsdóttir; Julio Sepúlveda
Marine fronts delineate the boundary between distinct water masses and, through the advection of nutrients, are important facilitators of regional productivity and biodiversity. As the modern climate continues to change, the migration of frontal zones is evident, but a lack of information about their status prior to instrumental records hinders future projections. Here, we combine data from lipid biomarkers
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Atmospheric CO2 estimates for the Miocene to Pleistocene based on foraminiferal δ11B at Ocean Drilling Program Sites 806 and 807 in the Western Equatorial Pacific Clim. Past (IF 3.536) Pub Date : 2021-02-08 Maxence Guillermic; Sambuddha Misra; Robert Eagle; Aradhna Tripati
Abstract. Constraints on the evolution of atmospheric CO2 levels throughout Earth's history are foundational to our understanding of past variations in climate. Despite considerable effort, estimates of past CO2 levels do not always converge and therefore new records and proxies are valuable. Here we reconstruct atmospheric CO2 values across major climate transitions over the past 17 million years
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Evolution of mean ocean temperature in Marine Isotope Stages 5-4 Clim. Past (IF 3.536) Pub Date : 2021-02-04 Sarah Shackleton; James A. Menking; Edward Brook; Christo Buizert; Michael N. Dyonisius; Vasilii V. Petrenko; Daniel Baggenstos; Jeffrey P. Severinghaus
Abstract. Deglaciations are characterized by relatively fast and near-synchronous changes in ice sheet volume, ocean temperature, and atmospheric greenhouse gas concentrations, but glacial inceptions occur more gradually. Understanding the evolution of ice sheet, ocean, and atmospheric conditions from interglacial to glacial maximum provides important insight into the interplay of these components
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Stalagmite carbon isotopes suggest deglacial increase in soil respiration in Western Europe driven by temperature change Clim. Past (IF 3.536) Pub Date : 2021-02-04 Franziska A. Lechleitner; Christopher C. Day; Oliver Kost; Micah Wilhelm; Negar Haghipour; Gideon M. Henderson; Heather M. Stoll
Abstract. The temperate region of Western Europe underwent dramatic climatic and environmental change during the last deglaciation. Much of what is known about the terrestrial ecosystem response to deglacial warming stems from pollen preserved in sediment sequences, providing information on vegetation composition. Other ecosystem processes, such as soil respiration, remain poorly constrained over past
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Reconstructing the evolution of ice sheets, sea level, and atmospheric CO2 during the past 3.6 million years Clim. Past (IF 3.536) Pub Date : 2021-02-01 Constantijn J. Berends; Bas de Boer; Roderik S. W. van de Wal
Understanding the evolution of, and the interactions between, ice sheets and the global climate over geological timescales is important for being able to project their future evolution. However, direct observational evidence of past CO2 concentrations, and the implied radiative forcing, only exists for the past 800 000 years. Records of benthic δ18O date back millions of years but contain signals from
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Glacial to interglacial climate variability in the southeastern African subtropics (25–20° S) Clim. Past (IF 3.536) Pub Date : 2021-01-29 Annette Hahn; Enno Schefuß; Jeroen Groeneveld; Charlotte Miller; Matthias Zabel
We present a continuous and well-resolved record of climatic variability for the past 100 000 years from a marine sediment core taken in Delagoa Bight, off southeastern Africa. In addition to providing a sea surface temperature reconstruction for the past ca. 100 000 years, this record also allows a high-resolution continental climatic reconstruction. Climate sensitive organic proxies, like the distribution
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The transient impact of the African monsoon on Plio-Pleistocene Mediterranean sediments Clim. Past (IF 3.536) Pub Date : 2021-01-29 Bas de Boer; Marit Peters; Lucas J. Lourens
Over the Plio-Pleistocene interval a strong linkage exists between northern African climate changes and the supply of dust over the surrounding oceans and continental runoff towards the Mediterranean Sea. Both these signatures in the sedimentary record are determined by orbital cycles influencing glacial variability on the one hand and northern African monsoon intensity on the other hand. In this paper
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Greenland climate simulations show high Eemian surface melt which could explain reduced total air content in ice cores Clim. Past (IF 3.536) Pub Date : 2021-01-29 Andreas Plach; Bo M. Vinther; Kerim H. Nisancioglu; Sindhu Vudayagiri; Thomas Blunier
This study presents simulations of Greenland surface melt for the Eemian interglacial period (∼130 000 to 115 000 years ago) derived from regional climate simulations with a coupled surface energy balance model. Surface melt is of high relevance due to its potential effect on ice core observations, e.g., lowering the preserved total air content (TAC) used to infer past surface elevation. An investigation
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The Eocene–Oligocene transition: a review of marine and terrestrial proxy data, models and model–data comparisons Clim. Past (IF 3.536) Pub Date : 2021-01-28 David K. Hutchinson; Helen K. Coxall; Daniel J. Lunt; Margret Steinthorsdottir; Agatha M. de Boer; Michiel Baatsen; Anna von der Heydt; Matthew Huber; Alan T. Kennedy-Asser; Lutz Kunzmann; Jean-Baptiste Ladant; Caroline H. Lear; Karolin Moraweck; Paul N. Pearson; Emanuela Piga; Matthew J. Pound; Ulrich Salzmann; Howie D. Scher; Willem P. Sijp; Kasia K. Śliwińska; Paul A. Wilson; Zhongshi Zhang
The Eocene–Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring ∼34 million years ago (Ma) and lasting ∼790 kyr. The change is marked by a global shift in deep-sea δ18O representing a combination of deep-ocean cooling and growth in land ice volume. At the same time
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Last Glacial Maximum (LGM) climate forcing and ocean dynamical feedback and their implications for estimating climate sensitivity Clim. Past (IF 3.536) Pub Date : 2021-01-27 Jiang Zhu; Christopher J. Poulsen
Equilibrium climate sensitivity (ECS) has been directly estimated using reconstructions of past climates that are different than today's. A challenge to this approach is that temperature proxies integrate over the timescales of the fast feedback processes (e.g., changes in water vapor, snow, and clouds) that are captured in ECS as well as the slower feedback processes (e.g., changes in ice sheets and
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The response of annual minimum temperature on the eastern central Tibetan Plateau to large volcanic eruptions over the period 1380–2014 CE Clim. Past (IF 3.536) Pub Date : 2021-01-26 Yajun Wang; Xuemei Shao; Yong Zhang; Mingqi Li
Volcanic eruptions have a significant impact on global temperature; their consequences are of particular interest in regions that are especially sensitive to climate change, like the Tibetan Plateau. In this study, we develop a temperature-sensitive tree-ring-width standard chronology covering the period 1348–2014 CE using Qilian juniper (Sabina przewalskii (Kom.)) samples collected from the Animaqin
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The unidentified volcanic eruption of 1809: why it remains a climatic cold case Clim. Past (IF 3.536) Pub Date : 2021-01-26 Claudia Timmreck; Matthew Toohey; Davide Zanchettin; Stefan Brönnimann; Elin Lundstadt; Rob Wilson
Abstract. The 1809 eruption is one of the most recent unidentified volcanic eruptions with a global climate impact. Even though the eruption ranks as the 3rd largest since 1500 with an eruption magnitude estimated to be two times that of the 1991 eruption of Pinatubo, not much is known of it from historic sources. Based on a compilation of instrumental and reconstructed temperature time series, we
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Influence of the representation of convection on the mid-Holocene West African Monsoon Clim. Past (IF 3.536) Pub Date : 2021-01-26 Leonore Jungandreas; Cathy Hohenegger; Martin Claussen
Abstract. Global climate models have difficulties to simulate the northward extension of the monsoonal precipitation over north Africa during the mid-Holocene as revealed by proxy data. A common feature of these models is that they usually operate on too coarse grids to explicitly resolve convection, but convection is the most essential mechanism leading to precipitation in the west African monsoon
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Exploring a link between the Middle Eocene Climatic Optimum and Neotethys continental arc flare-up Clim. Past (IF 3.536) Pub Date : 2021-01-18 Annique van der Boon; Klaudia F. Kuiper; Robin van der Ploeg; Margot J. Cramwinckel; Maryam Honarmand; Appy Sluijs; Wout Krijgsman
The Middle Eocene Climatic Optimum (MECO), a ∼500 kyr episode of global warming that initiated at ∼ 40.5 Ma, is postulated to be driven by a net increase in volcanic carbon input, but a direct source has not been identified. Here we show, based on new and previously published radiometric ages of volcanic rocks, that the interval spanning the MECO corresponds to a massive increase in continental arc
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Sequential changes in ocean circulation and biological export productivity during the last glacial–interglacial cycle: a model–data study Clim. Past (IF 3.536) Pub Date : 2021-01-15 Cameron M. O'Neill; Andrew McC. Hogg; Michael J. Ellwood; Bradley N. Opdyke; Stephen M. Eggins
We conduct a model–data analysis of the marine carbon cycle to understand and quantify the drivers of atmospheric CO2 concentration during the last glacial–interglacial cycle. We use a carbon cycle box model, “SCP-M”, combined with multiple proxy data for the atmosphere and ocean, to test for variations in ocean circulation and Southern Ocean biological export productivity across marine isotope stages
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DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data Clim. Past (IF 3.536) Pub Date : 2021-01-15 Daniel J. Lunt; Fran Bragg; Wing-Le Chan; David K. Hutchinson; Jean-Baptiste Ladant; Polina Morozova; Igor Niezgodzki; Sebastian Steinig; Zhongshi Zhang; Jiang Zhu; Ayako Abe-Ouchi; Eleni Anagnostou; Agatha M. de Boer; Helen K. Coxall; Yannick Donnadieu; Gavin Foster; Gordon N. Inglis; Gregor Knorr; Petra M. Langebroek; Caroline H. Lear; Gerrit Lohmann; Christopher J. Poulsen; Pierre Sepulchre; Jessica
We present results from an ensemble of eight climate models, each of which has carried out simulations of the early Eocene climate optimum (EECO, ∼ 50 million years ago). These simulations have been carried out in the framework of the Deep-Time Model Intercomparison Project (DeepMIP; http://www.deepmip.org, last access: 10 January 2021); thus, all models have been configured with the same paleogeographic
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El Niño–Southern Oscillation and internal sea surface temperature variability in the tropical Indian Ocean since 1675 Clim. Past (IF 3.536) Pub Date : 2021-01-15 Maike Leupold; Miriam Pfeiffer; Takaaki K. Watanabe; Lars Reuning; Dieter Garbe-Schönberg; Chuan-Chou Shen; Geert-Jan A. Brummer
The dominant modes of climate variability on interannual timescales in the tropical Indian Ocean are the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole. El Niño events have occurred more frequently during recent decades, and it has been suggested that an asymmetric ENSO teleconnection (warming during El Niño events is stronger than cooling during La Niña events) caused the pronounced
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Evaluating the utility of qualitative personal diaries in precipitation reconstruction in the eighteenth and nineteenth centuries Clim. Past (IF 3.536) Pub Date : 2021-01-14 Alice Harvey-Fishenden; Neil Macdonald
To date few studies have reconstructed weather from personal diaries (also known as private diaries). In this paper, we consider different methods of indexing daily weather information, specifically precipitation, from eighteenth and nineteenth-century personal diaries. We examine whether there is a significant correlation between indexed weather information and local instrumental records for the period
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FYRE Climate: A high-resolution reanalysis of daily precipitation and temperature in France from 1871 to 2012 Clim. Past (IF 3.536) Pub Date : 2021-01-13 Alexandre Devers; Jean-Philippe Vidal; Claire Lauvernet; Olivier Vannier
Abstract. Surface observations are usually too few and far between to properly assess multidecadal variations at the local scale and characterize historical local extreme events at the same time. A data assimilation scheme has been recently presented to assimilate daily observations of temperature and precipitation into downscaled reconstructions from a global extended reanalysis through an Ensemble
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Impact of mid-glacial ice sheets on deep ocean circulation and global climate Clim. Past (IF 3.536) Pub Date : 2021-01-12 Sam Sherriff-Tadano; Ayako Abe-Ouchi; Akira Oka
This study explores the effect of southward expansion of Northern Hemisphere (American) mid-glacial ice sheets on the global climate and the Atlantic Meridional Overturning Circulation (AMOC) as well as the processes by which the ice sheets modify the AMOC. For this purpose, simulations of Marine Isotope Stage (MIS) 3 (36 ka) and 5a (80 ka) are performed with an atmosphere–ocean general circulation
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Can we reconstruct the formation of large open-ocean polynyas in the Southern Ocean using ice core records? Clim. Past (IF 3.536) Pub Date : 2021-01-12 Hugues Goosse; Quentin Dalaiden; Marie G. P. Cavitte; Liping Zhang
Large open-ocean polynyas, defined as ice-free areas within the sea ice pack, have only rarely been observed in the Southern Ocean over the past decades. In addition to smaller recent events, an impressive sequence occurred in the Weddell Sea in 1974, 1975 and 1976 with openings of more than 300 000 km2 that lasted the full winter. These big events have a huge impact on the sea ice cover, deep-water
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Co-evolution of terrestrial and aquatic ecosystem structure with hydrological change in the Holocene Baltic Sea Clim. Past (IF 3.536) Pub Date : 2021-01-12 Gabriella M. Weiss; Julie Lattaud; Marcel T. J. van der Meer; Timothy I. Eglinton
Abstract. The Baltic Sea experienced a number of marine transgressions and regressions throughout the Holocene. These fluctuations in sea level coupled with substantial regional ice melt led to isostatic adjustment and periodic isolation from the North Sea. Here, we determine the distributions and isotopic signatures of organic compounds preserved in a sediment record spanning the last ~ 11 ka in order
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Large-scale features of Last Interglacial climate: results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)–Paleoclimate Modeling Intercomparison Project (PMIP4) Clim. Past (IF 3.536) Pub Date : 2021-01-11 Bette L. Otto-Bliesner; Esther C. Brady; Anni Zhao; Chris M. Brierley; Yarrow Axford; Emilie Capron; Aline Govin; Jeremy S. Hoffman; Elizabeth Isaacs; Masa Kageyama; Paolo Scussolini; Polychronis C. Tzedakis; Charles J. R. Williams; Eric Wolff; Ayako Abe-Ouchi; Pascale Braconnot; Silvana Ramos Buarque; Jian Cao; Anne de Vernal; Maria Vittoria Guarino; Chuncheng Guo; Allegra N. LeGrande; Gerrit Lohmann;
The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene
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A multi-model CMIP6-PMIP4 study of Arctic sea ice at 127 ka: sea ice data compilation and model differences Clim. Past (IF 3.536) Pub Date : 2021-01-11 Masa Kageyama; Louise C. Sime; Marie Sicard; Maria-Vittoria Guarino; Anne de Vernal; Ruediger Stein; David Schroeder; Irene Malmierca-Vallet; Ayako Abe-Ouchi; Cecilia Bitz; Pascale Braconnot; Esther C. Brady; Jian Cao; Matthew A. Chamberlain; Danny Feltham; Chuncheng Guo; Allegra N. LeGrande; Gerrit Lohmann; Katrin J. Meissner; Laurie Menviel; Polina Morozova; Kerim H. Nisancioglu; Bette L. Otto-Bliesner;
The Last Interglacial period (LIG) is a period with increased summer insolation at high northern latitudes, which results in strong changes in the terrestrial and marine cryosphere. Understanding the mechanisms for this response via climate modelling and comparing the models' representation of climate reconstructions is one of the objectives set up by the Paleoclimate Modelling Intercomparison Project
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Hydroclimatic variability of opposing late Pleistocene climates in the Levant revealed by deep Dead Sea sediments Clim. Past (IF 3.536) Pub Date : 2021-01-11 Yoav Ben Dor; Francesco Marra; Moshe Armon; Yehouda Enzel; Efrat Morin
Abstract. Annual and decadal-scale hydroclimatic variability is a key characteristic embedded into climate insitu. It is therefore crucial to study hydroclimatic variability in order to understand its effects on climate derivatives such as hydrological processes and water availability. However, the study of this variability from modern records is limited due to their relatively short span, whereas
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Overcoming model instability in tree-ring-based temperature reconstructions using a multi-species method: A case study from the Changbai Mountains, northeastern China Clim. Past (IF 3.536) Pub Date : 2021-01-11 Liangjun Zhu; Shuguang Liu; Haifeng Zhu; David J. Cooper; Danyang Yuan; Yu Zhu; Zongshan Li; Yuandong Zhang; Hanxue Liang; Xu Zhang; Wenqi Song; Xiaochun Wang
Abstract. The unstable sensitivity of growth-climate relationships greatly restricts tree-ring-based paleoclimate reconstructions, especially in areas with frequent divergence problems, such as the temperate zone in northeast China. Here, we propose an original tree-species mixing method to overcome this obstacle and improve the stability and reliability of reconstruction models. We take the tree-ring
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On the tuning of plateaus in atmospheric and oceanic 14C records to derive calendar chronologies of deep-sea cores and records of 14C marine reservoir age changes Clim. Past (IF 3.536) Pub Date : 2021-01-08 Edouard Bard; Timothy J. Heaton
Abstract. As an extended comment on the paper by Sarnthein et al. (2020), we express strong reservations about the methodology of the so-called 14C plateau tuning (PT) technique used to date marine sediment records and its implications on the determination of 14C marine reservoir ages (MRA). The main problems are linked to: the assumption of constant MRA during 14C-age plateaus; the lack of consideration
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PMIP4/CMIP6 last interglacial simulations using three different versions of MIROC: importance of vegetation Clim. Past (IF 3.536) Pub Date : 2021-01-06 Ryouta O'ishi; Wing-Le Chan; Ayako Abe-Ouchi; Sam Sherriff-Tadano; Rumi Ohgaito; Masakazu Yoshimori
We carry out three sets of last interglacial (LIG) experiments, named lig127k, and of pre-industrial experiments, named piControl, both as part of PMIP4/CMIP6 using three versions of the MIROC model: MIROC4m, MIROC4m-LPJ, and MIROC-ES2L. The results are compared with reconstructions from climate proxy data. All models show summer warming over northern high-latitude land, reflecting the differences
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Mid-Holocene Antarctic sea-ice increase driven by marine ice sheet retreat Clim. Past (IF 3.536) Pub Date : 2021-01-05 Kate E. Ashley; Robert McKay; Johan Etourneau; Francisco J. Jimenez-Espejo; Alan Condron; Anna Albot; Xavier Crosta; Christina Riesselman; Osamu Seki; Guillaume Massé; Nicholas R. Golledge; Edward Gasson; Daniel P. Lowry; Nicholas E. Barrand; Katelyn Johnson; Nancy Bertler; Carlota Escutia; Robert Dunbar; James A. Bendle
Over recent decades Antarctic sea-ice extent has increased, alongside widespread ice shelf thinning and freshening of waters along the Antarctic margin. In contrast, Earth system models generally simulate a decrease in sea ice. Circulation of water masses beneath large-cavity ice shelves is not included in current Earth System models and may be a driver of this phenomena. We examine a Holocene sediment
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Climate reconstructions based on GDGT and pollen surface datasets from Mongolia and Siberia: calibrations and applicability to extremely cold-dry environments over the Late Holocene Clim. Past (IF 3.536) Pub Date : 2020-12-29 Lucas Dugerdil; Sébastien Joannin; Odile Peyron; Isabelle Jouffroy-Bapicot; Boris Vannière; Boldgiv Bazartseren; Julia Unkelbach; Hermann Behling; Guillemette Ménot
Abstract. Our understanding of climate and vegetation changes throughout the Holocene is hampered by representativeness in sedimentary archives. Potential biases such as production and preservation of the markers are identified by comparing these proxies with modern environments. It is important to conduct multi-proxy studies and robust calibrations on each terrestrial biome. These calibrations use
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OPTiMAL: a new machine learning approach for GDGT-based palaeothermometry Clim. Past (IF 3.536) Pub Date : 2020-12-23 Tom Dunkley Jones; Yvette L. Eley; William Thomson; Sarah E. Greene; Ilya Mandel; Kirsty Edgar; James A. Bendle
In the modern oceans, the relative abundances of glycerol dialkyl glycerol tetraether (GDGT) compounds produced by marine archaeal communities show a significant dependence on the local sea surface temperature at the site of deposition. When preserved in ancient marine sediments, the measured abundances of these fossil lipid biomarkers thus have the potential to provide a geological record of long-term
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Plateaus and jumps in the atmospheric radiocarbon record – potential origin and value as global age markers for glacial-to-deglacial paleoceanography, a synthesis Clim. Past (IF 3.536) Pub Date : 2020-12-23 Michael Sarnthein; Kevin Küssner; Pieter M. Grootes; Blanca Ausin; Timothy Eglinton; Juan Muglia; Raimund Muscheler; Gordon Schlolaut
Changes in the geometry of ocean meridional overturning circulation (MOC) are crucial in controlling past changes of climate and the carbon inventory of the atmosphere. However, the accurate timing and global correlation of short-term glacial-to-deglacial changes of MOC in different ocean basins still present a major challenge. The fine structure of jumps and plateaus in atmospheric and planktic radiocarbon
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Holocene vegetation dynamics in response to climate change and hydrological processes in the Bohai region Clim. Past (IF 3.536) Pub Date : 2020-12-23 Chen Jinxia; Shi Xuefa; Liu Yanguang; Qiao Shuqing; Yang Shixiong; Yan Shijuan; Lv Huahua; Li Jianyong; Li Xiaoyan; Li Chaoxin
Coastal vegetation both mitigates the damage inflicted by marine disasters on coastal areas and plays an important role in the global carbon cycle (i.e., blue carbon). Nevertheless, detailed records of changes in coastal vegetation composition and diversity in the Holocene, coupled with climate change and river evolution, remain unclear. To explore vegetation dynamics and their influencing factors
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The middle to late Eocene greenhouse climate modelled using the CESM 1.0.5 Clim. Past (IF 3.536) Pub Date : 2020-12-23 Michiel Baatsen; Anna S. von der Heydt; Matthew Huber; Michael A. Kliphuis; Peter K. Bijl; Appy Sluijs; Henk A. Dijkstra
The early and late Eocene have both been the subject of many modelling studies, but few have focused on the middle Eocene. The latter still holds many challenges for climate modellers but is also key to understanding the events leading towards the conditions needed for Antarctic glaciation at the Eocene–Oligocene transition. Here, we present the results of CMIP5-like coupled climate simulations using
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Pliocene expansion of C4 vegetation in the Core Monsoon Zone on the Indian Peninsula Clim. Past (IF 3.536) Pub Date : 2020-12-23 Ann G. Dunlea; Liviu Giosan; Yongsong Huang
The expansion of C4 vegetation during the Neogene was one of the largest reorganizations of Earth's terrestrial biome. Once thought to be globally synchronous in the late Miocene, site-specific studies have revealed differences in the timing of the expansion and suggest that local conditions play a substantial role. Here, we examine the expansion of C4 vegetation on the Indian Peninsula since the late
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On the Role of Volcanism in Dansgaard-Oeschger Cycles Clim. Past (IF 3.536) Pub Date : 2020-12-23 Johannes Lohmann; Anders Svensson
Abstract. A significant influence of major volcanic eruptions on regime shifts and long-term climate variability has been suggested previously. But a statistical assessment of this has been hampered by inaccurate synchronization of large volcanic eruptions to changes in past climate. Here, this is achieved by combining a new record of bipolar volcanism from Greenland and Antarctic ice cores with records
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Evaluating seasonal sea-ice cover over the Southern Ocean from the Last Glacial Maximum Clim. Past (IF 3.536) Pub Date : 2020-12-22 Ryan A. Green; Laurie Menviel; Katrin J. Meissner; Xavier Crosta
Abstract. Sea-ice cover over the Southern Ocean responds to and impacts Southern Ocean dynamics and, thus, mid to high latitude climate in the Southern Hemisphere. In addition, sea-ice cover can significantly modulate the carbon exchange between the atmosphere and the ocean. As climate models are the only tool available to project future climate changes, it is important to assess their performance
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Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations Clim. Past (IF 3.536) Pub Date : 2020-12-21 Irene Malmierca-Vallet; Louise C. Sime; Paul J. Valdes; Julia C. Tindall
Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (δ18O) records from ice cores offer information on past changes in the surface of the GIS. Here, we use the isotope-enabled Hadley Centre Coupled Model version 3 (HadCM3) climate model to simulate a set of last interglacial (LIG) idealised GIS surface elevation change scenarios focusing on GIS ice core
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Aptian-Albian clumped isotopes from northwest China: Cool temperatures, variable atmospheric pCO2 and regional shifts in hydrologic cycle Clim. Past (IF 3.536) Pub Date : 2020-12-21 Dustin T. Harper; Marina B. Suarez; Jessica Uglesich; Hailu You; Daqing Li; Peter Dodson
Abstract. The Early Cretaceous is characterized by warm background temperatures (i.e., greenhouse climate) and carbon cycle perturbations that are often marked by Ocean Anoxic Events (OAEs) and associated shifts in the hydrologic cycle. Higher-resolution records of terrestrial and marine δ13C and δ18O (both carbonates and organics) suggest climate shifts during the Aptian-Albian, including a warm period
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Southern Ocean bottom water cooling and ice sheet expansion during the middle Miocene climate transition Clim. Past (IF 3.536) Pub Date : 2020-12-18 Thomas J. Leutert; Sevasti Modestou; Stefano M. Bernasconi; A. Nele Meckler
Abstract. The middle Miocene climate transition (MMCT, ~14.5–13.0 Ma) was associated with a significant expansion of Antarctic ice, but the mechanisms triggering the event remain enigmatic. We present a new clumped isotope (∆47) bottom water temperature (BWT) record from 16.0 Ma to 12.2 Ma from Ocean Drilling Program (ODP) Site 747 in the Southern Ocean, and compare it to existing BWT records. We show
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Sea ice dynamics in the Bransfield Strait, Antarctic Peninsula, during the past 240 years: a multi-proxy intercomparison study Clim. Past (IF 3.536) Pub Date : 2020-12-11 Maria-Elena Vorrath; Juliane Müller; Lorena Rebolledo; Paola Cárdenas; Xiaoxu Shi; Oliver Esper; Thomas Opel; Walter Geibert; Práxedes Muñoz; Christian Haas; Gerhard Kuhn; Carina B. Lange; Gerrit Lohmann; Gesine Mollenhauer
In the last decades, changing climate conditions have had a severe impact on sea ice at the western Antarctic Peninsula (WAP), an area rapidly transforming under global warming. To study the development of spring sea ice and environmental conditions in the pre-satellite era we investigated three short marine sediment cores for their biomarker inventory with a particular focus on the sea ice proxy IPSO25
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Stable isotopes in cave ice suggest summer temperatures in east-central Europe are linked to Atlantic Multidecadal Oscillation variability Clim. Past (IF 3.536) Pub Date : 2020-12-10 Carmen-Andreea Bădăluţă; Aurel Perșoiu; Monica Ionita; Natalia Piotrowska
The climate of east-central Europe (ECE) is the result of a combination of influences originating in the wider North Atlantic realm, the Mediterranean Sea, and the western Asian and Siberian regions. Previous studies have shown that the complex interplay between the large-scale atmospheric patterns across the region results in strongly dissimilar summer and winter conditions on timescales ranging from
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Mineral Dust Influence on the Glacial Nitrate Record from the RICE Ice Core, West Antarctica and Environmental Implications Clim. Past (IF 3.536) Pub Date : 2020-12-10 Abhijith U. Venugopal; Nancy A. N. Bertler; Rebecca L. Pyne; Helle A. Kjær; V. Holly L. Winton; Paul A. Mayewski; Giuseppe Cortese
Abstract. Nitrate (NO3−), an abundant aerosol in polar snow, is a complex environmental proxy to interpret owing to the variety of its sources and its susceptibility to post-depositional processes. During the last glacial period, when the dust level in the Antarctic atmosphere was higher than today by a factor up to ~25, mineral dust appears to have a stabilizing effect on the NO3− concentration. However
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The SP19 chronology for the South Pole Ice Core – Part 2: gas chronology, Δage, and smoothing of atmospheric records Clim. Past (IF 3.536) Pub Date : 2020-12-03 Jenna A. Epifanio; Edward J. Brook; Christo Buizert; Jon S. Edwards; Todd A. Sowers; Emma C. Kahle; Jeffrey P. Severinghaus; Eric J. Steig; Dominic A. Winski; Erich C. Osterberg; Tyler J. Fudge; Murat Aydin; Ekaterina Hood; Michael Kalk; Karl J. Kreutz; David G. Ferris; Joshua A. Kennedy
A new ice core drilled at the South Pole provides a 54 000-year paleoenvironmental record including the composition of the past atmosphere. This paper describes the SP19 chronology for the South Pole atmospheric gas record and complements a previous paper (Winski et al., 2019) describing the SP19 ice chronology. The gas chronology is based on a discrete methane (CH4) record with 20- to 190-year resolution
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Variations in mineralogy of dust in an ice core obtained from northwestern Greenland over the past 100 years Clim. Past (IF 3.536) Pub Date : 2020-12-03 Naoko Nagatsuka; Kumiko Goto-Azuma; Akane Tsushima; Koji Fujita; Sumito Matoba; Yukihiko Onuma; Moe Kadota; Masahiro Minowa; Yuki Komuro; Hideaki Motoyama; Teruo Aoki
Abstract. Our study is the first to demonstrate a high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years. To reconstruct the past variations in the sources and transportation processes of mineral dust in northwestern Greenland, we analyzed the morphology and mineralogical composition of dust in an ice core from 1915 to 2013 using Scanning Electron Microscopy
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