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description Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023Publisher:Copernicus GmbH V. Mikhalenko; S. Kutuzov; S. Kutuzov; S. Kutuzov; P. Toropov; P. Toropov; M. Legrand; M. Legrand; S. Sokratov; G. Chernyakov; I. Lavrentiev; S. Preunkert; A. Kozachek; M. Vorobiev; A. Khairedinova; V. Lipenkov; V. Lipenkov;Abstract. In this study, we present a seasonally resolved accumulation record spanning from 1750 to 2009 Common Era (CE), based on a 181.8 m ice core obtained from the Elbrus Western Plateau in the Caucasus. We implemented various methods to account for uncertainties associated with glacier flow, layer thinning, and dating. Additionally, we applied a novel approach to calculate a seasonal calendar for meteorological data, enabling comparison with ice core records. The reconstructed accumulation data were compared with available meteorological data, gridded precipitation records, and paleo-reanalysis data. Reconstructed accumulation is representative for a large region south of the Eastern European plain and Black Sea region with summer precipitation being the primary driver of precipitation variability. We identified a statistically significant relationship between changes in regional precipitation and fluctuations in the North Atlantic Oscillation (NAO) index, which is, however, not stable over the entire period covered by the ice core.
Climate of the Past ... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 GermanyPublisher:Copernicus GmbH Funded by:SNSF | Climate and Environmental..., UKRI | Revisiting the role of oc..., UKRI | Resolving the ocean's rol...SNSF| Climate and Environmental Physics: Modeling Global Biogeochemical Cycles in the Earth System 2021-2025 (bgcCEP20) ,UKRI| Revisiting the role of ocean ventilation in glacial CO2 sequestration using radiocarbon (ROGUE14) ,UKRI| Resolving the ocean's role in deglacial radiocarbon cycling (OCEAN-14)L. Skinner; F. Primeau; A. Jeltsch-Thömmes; A. Jeltsch-Thömmes; F. Joos; F. Joos; P. Köhler; E. Bard;Radiocarbon is a tracer that provides unique insights into the ocean's ability to sequester CO2 from the atmosphere. While spatial patterns of radiocarbon in the ocean interior can indicate the vectors and timescales for carbon transport through the ocean, estimates of the global average ocean–atmosphere radiocarbon age offset (B-Atm) place constraints on the closure of the global carbon cycle. Here, we apply a Bayesian interpolation method to compiled B-Atm data to generate global interpolated fields and mean ocean B-Atm estimates for a suite of time slices across the last deglaciation. The compiled data and interpolations confirm a stepwise and spatially heterogeneous “rejuvenation” of the ocean, suggesting that carbon was released to the atmosphere through two swings of a “ventilation seesaw” operating between the North Atlantic and both the Southern Ocean and the North Pacific. Sensitivity tests using the Bern3D model of intermediate complexity demonstrate that a portion of the reconstructed deglacial B-Atm changes may reflect “phase-attenuation” biases that are unrelated to ocean ventilation and that arise from independent atmospheric radiocarbon dynamics instead. A deglacial minimum in B-Atm offsets during the Bølling–Allerød could partly reflect such a bias. However, the sensitivity tests further demonstrate that when correcting for such biases, ocean “ventilation” could still account for at least one-third of deglacial atmospheric CO2 rise. This contribution to CO2 rise appears to have continued through the Younger Dryas, though much of the impact was likely achieved by the end of the Bølling–Allerød, indicating a key role for marine carbon cycle adjustment early in the deglacial process. Our global average B-Atm estimates place further new constraints on the long-standing mystery of global radiocarbon budget closure across the last deglaciation and suggest that glacial radiocarbon production levels are likely underestimated on average by existing reconstructions.
Electronic Publicati... arrow_drop_down Electronic Publication Information CenterArticle . 2023Data sources: Electronic Publication Information CenterCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-24&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert Electronic Publicati... arrow_drop_down Electronic Publication Information CenterArticle . 2023Data sources: Electronic Publication Information CenterCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-24&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 France, Denmark, United Kingdom, SwitzerlandPublisher:Copernicus GmbH Funded by:NSF | Biomass Burning, Dust, Se..., NSF | Collaborative Research: C..., EC | ICE&LASERS +4 projectsNSF| Biomass Burning, Dust, Sea Salt, Volcanic & Pollution Aerosols in the Arctic during the Last 2 Millennia: High Resolution Aerosol Records from NEEM & an Aray of Archived Ice Cores ,NSF| Collaborative Research: Continuous Records of Greenhouse Gases and Aerosol Deposition During the Holocene: Testing the Fidelity of New Methods for Reconstructing Atmospheric Change ,EC| ICE&LASERS ,EC| PEGASOS ,NSF| Development of High-Resolution, Multi-Century Records of Trace Element Deposition in West-Central Greenland Using ICP-MS ,NSF| Collaborative Research: Reconstruction of Carbon Monoxide in the Pre-Industrial Arctic Atmosphere from Ice Cores at Summit, Greenland ,NSF| PIRE: International Collaboration and Education in Ice Core Science (ICE-ICS)X. Faïn; D. M. Etheridge; D. M. Etheridge; K. Fourteau; P. Martinerie; C. M. Trudinger; C. M. Trudinger; R. H. Rhodes; N. J. Chellman; R. L. Langenfelds; J. R. McConnell; M. A. J. Curran; M. A. J. Curran; E. J. Brook; T. Blunier; G. Teste; R. Grilli; A. Lemoine; W. T. Sturges; B. Vannière; B. Vannière; J. Freitag; J. Chappellaz; J. Chappellaz;Abstract. Carbon monoxide (CO) is a naturally occurring atmospheric trace gas, a regulated pollutant, and one of the main components determining the oxidative capacity of the atmosphere. Evaluating climate–chemistry models under different conditions than today and constraining past CO sources requires a reliable record of atmospheric CO mixing ratios ([CO]) that includes data since preindustrial times. Here, we report the first continuous record of atmospheric [CO] for Southern Hemisphere (SH) high latitudes over the past 3 millennia. Our continuous record is a composite of three high-resolution Antarctic ice core gas records and firn air measurements from seven Antarctic locations. The ice core gas [CO] records were measured by continuous flow analysis (CFA), using an optical feedback cavity-enhanced absorption spectrometer (OF-CEAS), achieving excellent external precision (2.8–8.8 ppb; 2σ) and consistently low blanks (ranging from 4.1±1.2 to 7.4±1.4 ppb), thus enabling paleo-atmospheric interpretations. Six new firn air [CO] Antarctic datasets collected between 1993 and 2016 CE at the DE08-2, DSSW19K, DSSW20K, South Pole, Aurora Basin North (ABN), and Lock-In sites (and one previously published firn CO dataset at Berkner) were used to reconstruct the atmospheric history of CO from ∼1897 CE, using inverse modeling that incorporates the influence of gas transport in firn. Excellent consistency was observed between the youngest ice core gas [CO] and the [CO] from the base of the firn and between the recent firn [CO] and atmospheric [CO] measurements at Mawson station (eastern Antarctica), yielding a consistent and contiguous record of CO across these different archives. Our Antarctic [CO] record is relatively stable from −835 to 1500 CE, with mixing ratios within a 30–45 ppb range (2σ). There is a ∼5 ppb decrease in [CO] to a minimum at around 1700 CE during the Little Ice Age. CO mixing ratios then increase over time to reach a maximum of ∼54 ppb by ∼1985 CE. Most of the industrial period [CO] growth occurred between about 1940 to 1985 CE, after which there was an overall [CO] decrease, as observed in Greenland firn air and later at atmospheric monitoring sites and attributed partly to reduced CO emissions from combustion sources. Our Antarctic ice core gas CO observations differ from previously published records in two key aspects. First, our mixing ratios are significantly lower than reported previously, suggesting that previous studies underestimated blank contributions. Second, our new CO record does not show a maximum in the late 1800s. The absence of a [CO] peak around the turn of the century argues against there being a peak in Southern Hemisphere biomass burning at this time, which is in agreement with (i) other paleofire proxies such as ethane or acetylene and (ii) conclusions reached by paleofire modeling. The combined ice core and firn air [CO] history, spanning −835 to 1992 CE, extended to the present by the Mawson atmospheric record, provides a useful benchmark for future atmospheric chemistry modeling studies. International audience
Mémoires en Sciences... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsCopenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert Mémoires en Sciences... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsCopenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-9&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Other literature type , Article , Preprint 2023 FrancePublisher:Copernicus GmbH E. Queiroz Alves; E. Queiroz Alves; W. Wong; W. Wong; W. Wong; J. Hefter; H. Grotheer; H. Grotheer; T. Tesi; T. Gentz; K. Zonneveld; G. Mollenhauer; G. Mollenhauer; G. Mollenhauer;The last deglaciation is the most recent relatively well-documented period of pronounced and fast climate warming, and, as such, it holds important information for our understanding of the climate system. Notably, while research into terrestrial organic carbon reservoirs has been instrumental in exploring the possible sources of atmospheric carbon dioxide during periods of rapid change, the underlying mechanisms are not fully understood. Here we investigate the mobilization of organic matter to the Bay of Biscay, located in the north-eastern Atlantic Ocean off the coasts of France and Spain. Specifically, we focus on the area that was the mouth of the Channel River during the last deglaciation, where an enhanced terrigenous input has been reported for the last glacial–interglacial transition. We conducted a comprehensive suite of biomarker analyses (e.g. n-alkanes, hopanes and n-alkanoic acids) and isotopic investigations (radiocarbon dating and δ13C measurements) on a high-resolution sedimentary archive. The present study provides the first direct evidence for the fluvial supply of immature and ancient terrestrial organic matter to the core location. Moreover, our results reveal the possibility of permafrost carbon export to the ocean, driven by processes such as deglacial warming and glacial erosion. These findings are consistent with observations from other regions characterized by present or past permafrost conditions on land, which have shown that permafrost thaw and glacial erosion can lead to carbon remobilization, potentially influencing atmospheric carbon dioxide levels.
ArchiMer - Instituti... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert ArchiMer - Instituti... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 Netherlands, Spain, FrancePublisher:Copernicus GmbH Funded by:NWO | TRIGGER – Tracing the Reg..., EC | OceaNiceNWO| TRIGGER – Tracing the Regional Initiator of the Great Global Eocene plate Reorganization ,EC| OceaNiceF. S. Hoem; A. López-Quirós; A. López-Quirós; S. van de Lagemaat; J. Etourneau; J. Etourneau; M.-A. Sicre; C. Escutia; H. Brinkhuis; H. Brinkhuis; F. Peterse; F. Sangiorgi; P. K. Bijl;handle: 10261/344893
At present, a strong latitudinal sea-surface-temperature (SST) gradient of g1/4g€¯16g€¯g exists across the Southern Ocean, maintained by the Antarctic Circumpolar Current (ACC) and a set of complex frontal systems. Together with the Antarctic ice masses, this system has formed one of the most important global climate regulators. The timing of the onset of the ACC system, its development towards modern-day strength and the consequences for the latitudinal SST gradient around the southern Atlantic Ocean are still uncertain. Here we present new TEX86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms)-derived SST records from two sites located east of Drake Passage (south-western South Atlantic) to assist in better understanding two critical time intervals of prominent climate transitions during the Cenozoic: the late Eocene-early Oligocene (Ocean Drilling Program, ODP, Site 696) and Middle-Late Miocene (IODP Site U1536) transitions. Our results show temperate conditions (20-11g€¯g) during the first time interval, with a weaker latitudinal SST gradient (g1/4g€¯8g€¯g) across the Atlantic sector of the Southern Ocean compared to present day. We ascribe the similarity in SSTs between Sites 696 and 511 in the late Eocene-early Oligocene South Atlantic to a persistent, strong subpolar gyre circulation connecting the sites, which can only exist in the absence of a strong throughflow across the Drake Passage. Surprisingly, the southern South Atlantic record Site 696 shows comparable SSTs (g1/4g€¯12-14g€¯g) during both the earliest Oligocene oxygen isotope step (EOIS, g1/4g€¯33.65g€¯Ma) and the Miocene Climatic Optimum (MCO, g1/4g€¯16.5g€¯Ma). Apparently, maximum Oligocene Antarctic ice volume could coexist with warm ice-proximal surface ocean conditions, while at similar ocean temperatures, the Middle Miocene Antarctic ice sheet was likely reduced. Only a few Middle-Late Miocene (discontinuous) high-latitude records exist due to ice advances causing unconformities. Our low-resolution Site U1536 record of southern South Atlantic SSTs cooled to g1/4g€¯5g€¯g during the Middle Miocene Climate Transition (MMCT, 14g€¯Ma), making it the coldest oceanic region in the poorly recorded Antarctic realm and likely the main location for deep-water formation. The already-cold south-western South Atlantic conditions at the MMCT with relatively moderate additional cooling during the Late Miocene contrasts with the profound cooling in the lower latitudes and other sectors of the Southern Ocean due to northward expansion of the Southern Ocean frontal systems. This work used International Ocean Discovery Program (IODP) archived samples and data. We thank the great scientists and crew on Expedition 382, who also helped with data interpretation and discussions of results from Site U1536. We thank Mariska Hoorweg for technical support at the Utrecht University GeoLab. Frida S. Hoem and Peter K. Bijl acknowledge funding from the ERC starting grant 802835 “OceanNice”. Carlota Escutia and Adrián López-Quirós acknowledge funding provided by the Spanish Ministry of Science and Innovation (grants CTM2014-60451-C2-1/2-P and CTM2017-89711-C2-1/2-P, co-funded by the European Union through FEDER funds) and JUAN DE LA CIERVA-TRAINING AID 2021 (FJC2021-047046-I, MCIN/AEI/10.13039/501100011033 and NextGenerationEU/PRTR). Suzanna van de Lagemaat acknowledges funding by NWO Vici (grant no. 865.17.001) awarded to Douwe van Hinsbergen. This research has been supported by the Dutch Research Council (NWO) Polar Programme (grant no. ALW.2016.001).
Climate of the Past ... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsHAL Descartes; Mémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYFull-Text: https://hal.science/hal-04283114/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsHAL Descartes; Mémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYFull-Text: https://hal.science/hal-04283114/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint , Other literature type , Article 2023 FrancePublisher:Copernicus GmbH Funded by:FCT | LA 1, UKRI | Live Automated Materials ...FCT| LA 1 ,UKRI| Live Automated Materials Plan (LAMP)P. Meister; A. Alexandre; H. Bailey; P. Barker; B. K. Biskaborn; E. Broadman; R. Cartier; R. Cartier; B. Chapligin; M. Couapel; J. R. Dean; B. Diekmann; B. Diekmann; P. Harding; P. Harding; A. C. G. Henderson; A. Hernandez; U. Herzschuh; U. Herzschuh; U. Herzschuh; S. S. Kostrova; J. Lacey; M. J. Leng; M. J. Leng; A. Lücke; A. W. Mackay; E. K. Magyari; B. Narancic; B. Narancic; C. Porchier; G. Rosqvist; A. Shemesh; C. Sonzogni; G. E. A. Swann; F. Sylvestre; H. Meyer;Oxygen isotopes in biogenic silica (δ18OBSi) from lake sediments allow for quantitative reconstruction of past hydroclimate and proxy–model comparison in terrestrial environments. The signals of individual records have been attributed to different factors, such as air temperature (Tair), atmospheric circulation patterns, hydrological changes and lake evaporation. While every lake will have its own set of drivers of d18O, here we explore the extent to which regional or even global signals emerge from a series of palaeoenvironmental records. For this purpose, we have identified and compiled 71 down–core records published to date and complemented these datasets with additional lake basin parameters (e.g. lake water residence time and catchment size) to best characterize the signal properties. Records feature widely different temporal coverage and resolution ranging from decadal–scale records covering the last 150 years to records with multi–millennial scale resolution spanning glacial–interglacial cycles. Best coverage in number of records (N = 37) and datapoints (N = 2112) is available for northern hemispheric (NH) extra–tropic regions throughout the Holocene (corresponding to Marine Isotope Stage 1; MIS 1). To address the different variabilities and temporal offsets, records were brought to a common temporal resolution by binning and subsequently filtered for hydrologically open lakes with lake water residence times 45° N) lakes, we find common δ18OBSi patterns during both the Holocene and the Common Era and maxima and minima corresponding to known climate episodes such as the Holocene Thermal Maximum (HTM), Neoglacial Cooling, Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). These patterns are in line with long–term Tair changes supported by previously published climate reconstructions from other archives as well as Holocene summer insolation changes. In conclusion, oxygen isotope records from NH extratopic lake sediments feature a common climate signal at centennial (for CE) and millennial (for Holocene) time scales despite stemming from different lakes in different geographic locations and constitute a valuable proxy for past climate reconstructions. International audience
https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefMémoires en Sciences de l'Information et de la Communication; HAL AMU; HAL-IRDPreprint . 2023License: CC BYFull-Text: https://hal.science/hal-04304267/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-96&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefMémoires en Sciences de l'Information et de la Communication; HAL AMU; HAL-IRDPreprint . 2023License: CC BYFull-Text: https://hal.science/hal-04304267/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-96&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint , Other literature type , Article 2023 FrancePublisher:Copernicus GmbH L. Su; L. Su; J. Ren; M.-A. Sicre; Y. Bai; R. Zhao; R. Zhao; X. Han; Z. Li; H. Jin; H. Jin; A. S. Astakhov; X. Shi; J. Chen; J. Chen;Decreasing sea ice extent caused by climate change is affecting the carbon cycle of the Arctic Ocean. In this study, surface sediments across the western Arctic Ocean are investigated to characterize sources of sedimentary organic carbon (OC). Bulk organic parameters (total organic carbon, total nitrogen, δ13Corg, and δ15N) and molecular organic biomarkers (e.g., sterols and highly branched isoprenoids - HBIs) are combined to distinguish between sympagic, pelagic, and terrestrial OC sources. Their downcore profiles generated at the Chukchi Sea R1 core site (74∘ N) are then used to evaluate changes in the relative contribution of these components of sedimentary OC over the last 200 years with decreasing sea ice. Our data evidence that, from the 1820s to the 1930s, prevailing high sea ice cover inhibited in situ primary production, resulting in prominent land-derived material in sediments. Then, from the 1930s to the 1980s, primary production started increasing with the gradual decline of summer sea ice. The ratio of sympagic and pelagic OC began to rise to account for the larger portion of sedimentary OC. Since the 1980s, accelerated sea ice loss led to enhanced primary production, stabilizing over the last decades due to freshwater-induced surface ocean stratification in summer. International audience
https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsMémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2023-64&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsMémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2023-64&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 FrancePublisher:Copernicus GmbH Julia Rieke Hagemann; Lester Lembke-Jene; Frank Lamy; Maria-Elena Vorrath; Jérôme Kaiser; Juliane Müller; Helge W. Arz; Jens Hefter; Andrea Jaeschke; Nicoletta Ruggieri; Ralf Tiedemann;As remnants of living organisms, alkenones and isoprenoid glycerol dialkyl glycerol tetraether lipids (isoGDGTs) are widely used biomarkers for determining ocean water temperatures from the past. The organisms that these proxy carriers stem from are influenced by a number of environmental parameters, such as water depth, nutrient availability, light conditions, or seasonality, which all may significantly bias the calibration to ambient water temperatures. Reliable temperature determinations thus remain challenging, especially in higher latitudes and for undersampled regions. We analyzed 33 sediment surface samples from the southern Chilean continental margin and the Drake Passage for alkenones and isoGDGTs and compared the results with gridded instrumental reference data from the World Ocean Atlas 2005 (WOA05) and previously published data from an extended study area covering the central and western South Pacific towards the Aotearoa / New Zealand continental margin. We show that for alkenone-derived sea surface temperatures (SSTs), the widely used global core-top calibration of Müller et al. (1998) yields the smallest deviation of the WOA05-based SSTs. On the contrary, the calibration of Sikes et al. (1997), determined for higher latitudes and summer SSTs, overestimates modern WOA05-based SSTs in both the annual mean and summer. Our alkenone SSTs show a slight seasonal shift of ∼ 1 ∘C at the southern Chilean margin and up to ∼ 2 ∘C in the Drake Passage towards austral summer SSTs. Samples in the central South Pacific, on the other hand, reflect an annual mean signal. We show that for isoGDGT-based temperatures, the subsurface calibration of Kim et al. (2012a) best reflects temperatures from the WOA05 in areas north of the Subantarctic Front (SAF). Temperatures south of the SAF are, in contrast, significantly overestimated by up to 14 ∘C, irrespective of the applied calibration. In addition, we used the GDGT [2]/[3] ratios, which give an indication of the production depth of the isoGDGTs and/or potential influences from land. Our samples reflect a subsurface (0–200 m water depth) rather than a surface (0–50 m water depth) signal in the entire study area and show a correlation with the monthly dust distribution in the South Pacific, indicating terrigenous influences. The overestimation of isoGDGT surface and subsurface temperatures south of the SAF highlights the need for a reassessment of existing calibrations in the polar Southern Ocean. Therefore, we suggest a modified Southern Ocean tetraether index (TEX86)-based calibration for surface and subsurface temperatures, which shows a lower temperature sensitivity and yields principally lower absolute temperatures, which align more closely with WOA05-derived values and also OH–isoGDGT-derived temperatures.
Climate of the Past ... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/egusph...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2022-1456&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/egusph...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2022-1456&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 Switzerland, France, DenmarkPublisher:Copernicus GmbH A. P. M. Servettaz; A. P. M. Servettaz; A. J. Orsi; A. J. Orsi; M. A. J. Curran; M. A. J. Curran; A. D. Moy; A. D. Moy; A. Landais; J. R. McConnell; T. J. Popp; E. Le Meur; X. Faïn; J. Chappellaz; J. Chappellaz;The temperature of the Earth is one of the most important climate parameters. Proxy records of past climate changes, in particular temperature, represent a fundamental tool for exploring internal climate processes and natural climate forcings. Despite the excellent information provided by ice core records in Antarctica, the temperature variability of the past 2000 years is difficult to evaluate from the low-accumulation sites in the Antarctic continent interior. Here we present the results from the Aurora Basin North (ABN) ice core (71∘ S, 111∘ E, 2690 m a.s.l.) in the lower part of the East Antarctic plateau, where accumulation is substantially higher than other ice core drilling sites on the plateau, and provide unprecedented insight into East Antarctic past temperature variability. We reconstructed the temperature of the last 2000 years using two independent methods: the widely used water stable isotopes (δ18O) and by inverse modelling of borehole temperature and past temperature gradients estimated from the inert gas stable isotopes (δ40Ar and δ15N). This second reconstruction is based on three independent measurement types: borehole temperature, firn thickness, and firn temperature gradient. The δ18O temperature reconstruction supports stable temperature conditions within 1 ∘C over the past 2000 years, in agreement with other ice core δ18O records in the region. However, the gas and borehole temperature reconstruction suggests that surface conditions 2 ∘C cooler than average prevailed in the 1000–1400 CE period and supports a 20th century warming of 1 ∘C. A precipitation hiatus during cold periods could explain why water isotope temperature reconstruction underestimates the temperature changes. Both reconstructions arguably record climate in their own way, with a focus on atmospheric and hydrologic cycles for water isotopes, as opposed to surface temperature for gas isotopes and boreholes. This study demonstrates the importance of using a variety of sources for comprehensive paleoclimate reconstructions. International audience
Mémoires en Sciences... arrow_drop_down Copenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-91&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 3 citations 3 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert Mémoires en Sciences... arrow_drop_down Copenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-91&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 France, Portugal, NorwayPublisher:Copernicus GmbH Funded by:EC | ACCLIMATE, EC | ICE2ICEEC| ACCLIMATE ,EC| ICE2ICEC. Waelbroeck; J. Tjiputra; C. Guo; K. H. Nisancioglu; E. Jansen; E. Jansen; N. Vázquez Riveiros; S. Toucanne; F. Eynaud; L. Rossignol; F. Dewilde; E. Marchès; S. Lebreiro; S. Nave;handle: 10400.9/4144 , 11250/3074362
Abstract. We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry in order to interpret the observed Cibicides δ13C changes at the stadial–interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides δ13C observed at the end of HS4 between ∼2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high-latitude glacial North Atlantic. Our model results show that this Cibicides δ13C signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep-water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from ∼40 % at 2000 m to ∼80 % at 4000 m. Below ∼4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials compared to during interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies. International audience
HAL-CEA; HAL-IRD arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of Ifremerhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsBergen Open Research Archive - UiB; Norwegian Open Research ArchivesArticle . 2023 . Peer-reviewedLicense: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-83&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!visibility 17visibility views 17 download downloads 6 Powered bymore_vert HAL-CEA; HAL-IRD arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of Ifremerhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsBergen Open Research Archive - UiB; Norwegian Open Research ArchivesArticle . 2023 . Peer-reviewedLicense: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-83&type=result"></script>'); --> </script>
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description Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023Publisher:Copernicus GmbH V. Mikhalenko; S. Kutuzov; S. Kutuzov; S. Kutuzov; P. Toropov; P. Toropov; M. Legrand; M. Legrand; S. Sokratov; G. Chernyakov; I. Lavrentiev; S. Preunkert; A. Kozachek; M. Vorobiev; A. Khairedinova; V. Lipenkov; V. Lipenkov;Abstract. In this study, we present a seasonally resolved accumulation record spanning from 1750 to 2009 Common Era (CE), based on a 181.8 m ice core obtained from the Elbrus Western Plateau in the Caucasus. We implemented various methods to account for uncertainties associated with glacier flow, layer thinning, and dating. Additionally, we applied a novel approach to calculate a seasonal calendar for meteorological data, enabling comparison with ice core records. The reconstructed accumulation data were compared with available meteorological data, gridded precipitation records, and paleo-reanalysis data. Reconstructed accumulation is representative for a large region south of the Eastern European plain and Black Sea region with summer precipitation being the primary driver of precipitation variability. We identified a statistically significant relationship between changes in regional precipitation and fluctuations in the North Atlantic Oscillation (NAO) index, which is, however, not stable over the entire period covered by the ice core.
Climate of the Past ... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-46&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-46&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 GermanyPublisher:Copernicus GmbH Funded by:SNSF | Climate and Environmental..., UKRI | Revisiting the role of oc..., UKRI | Resolving the ocean's rol...SNSF| Climate and Environmental Physics: Modeling Global Biogeochemical Cycles in the Earth System 2021-2025 (bgcCEP20) ,UKRI| Revisiting the role of ocean ventilation in glacial CO2 sequestration using radiocarbon (ROGUE14) ,UKRI| Resolving the ocean's role in deglacial radiocarbon cycling (OCEAN-14)L. Skinner; F. Primeau; A. Jeltsch-Thömmes; A. Jeltsch-Thömmes; F. Joos; F. Joos; P. Köhler; E. Bard;Radiocarbon is a tracer that provides unique insights into the ocean's ability to sequester CO2 from the atmosphere. While spatial patterns of radiocarbon in the ocean interior can indicate the vectors and timescales for carbon transport through the ocean, estimates of the global average ocean–atmosphere radiocarbon age offset (B-Atm) place constraints on the closure of the global carbon cycle. Here, we apply a Bayesian interpolation method to compiled B-Atm data to generate global interpolated fields and mean ocean B-Atm estimates for a suite of time slices across the last deglaciation. The compiled data and interpolations confirm a stepwise and spatially heterogeneous “rejuvenation” of the ocean, suggesting that carbon was released to the atmosphere through two swings of a “ventilation seesaw” operating between the North Atlantic and both the Southern Ocean and the North Pacific. Sensitivity tests using the Bern3D model of intermediate complexity demonstrate that a portion of the reconstructed deglacial B-Atm changes may reflect “phase-attenuation” biases that are unrelated to ocean ventilation and that arise from independent atmospheric radiocarbon dynamics instead. A deglacial minimum in B-Atm offsets during the Bølling–Allerød could partly reflect such a bias. However, the sensitivity tests further demonstrate that when correcting for such biases, ocean “ventilation” could still account for at least one-third of deglacial atmospheric CO2 rise. This contribution to CO2 rise appears to have continued through the Younger Dryas, though much of the impact was likely achieved by the end of the Bølling–Allerød, indicating a key role for marine carbon cycle adjustment early in the deglacial process. Our global average B-Atm estimates place further new constraints on the long-standing mystery of global radiocarbon budget closure across the last deglaciation and suggest that glacial radiocarbon production levels are likely underestimated on average by existing reconstructions.
Electronic Publicati... arrow_drop_down Electronic Publication Information CenterArticle . 2023Data sources: Electronic Publication Information CenterCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-24&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert Electronic Publicati... arrow_drop_down Electronic Publication Information CenterArticle . 2023Data sources: Electronic Publication Information CenterCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-24&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 France, Denmark, United Kingdom, SwitzerlandPublisher:Copernicus GmbH Funded by:NSF | Biomass Burning, Dust, Se..., NSF | Collaborative Research: C..., EC | ICE&LASERS +4 projectsNSF| Biomass Burning, Dust, Sea Salt, Volcanic & Pollution Aerosols in the Arctic during the Last 2 Millennia: High Resolution Aerosol Records from NEEM & an Aray of Archived Ice Cores ,NSF| Collaborative Research: Continuous Records of Greenhouse Gases and Aerosol Deposition During the Holocene: Testing the Fidelity of New Methods for Reconstructing Atmospheric Change ,EC| ICE&LASERS ,EC| PEGASOS ,NSF| Development of High-Resolution, Multi-Century Records of Trace Element Deposition in West-Central Greenland Using ICP-MS ,NSF| Collaborative Research: Reconstruction of Carbon Monoxide in the Pre-Industrial Arctic Atmosphere from Ice Cores at Summit, Greenland ,NSF| PIRE: International Collaboration and Education in Ice Core Science (ICE-ICS)X. Faïn; D. M. Etheridge; D. M. Etheridge; K. Fourteau; P. Martinerie; C. M. Trudinger; C. M. Trudinger; R. H. Rhodes; N. J. Chellman; R. L. Langenfelds; J. R. McConnell; M. A. J. Curran; M. A. J. Curran; E. J. Brook; T. Blunier; G. Teste; R. Grilli; A. Lemoine; W. T. Sturges; B. Vannière; B. Vannière; J. Freitag; J. Chappellaz; J. Chappellaz;Abstract. Carbon monoxide (CO) is a naturally occurring atmospheric trace gas, a regulated pollutant, and one of the main components determining the oxidative capacity of the atmosphere. Evaluating climate–chemistry models under different conditions than today and constraining past CO sources requires a reliable record of atmospheric CO mixing ratios ([CO]) that includes data since preindustrial times. Here, we report the first continuous record of atmospheric [CO] for Southern Hemisphere (SH) high latitudes over the past 3 millennia. Our continuous record is a composite of three high-resolution Antarctic ice core gas records and firn air measurements from seven Antarctic locations. The ice core gas [CO] records were measured by continuous flow analysis (CFA), using an optical feedback cavity-enhanced absorption spectrometer (OF-CEAS), achieving excellent external precision (2.8–8.8 ppb; 2σ) and consistently low blanks (ranging from 4.1±1.2 to 7.4±1.4 ppb), thus enabling paleo-atmospheric interpretations. Six new firn air [CO] Antarctic datasets collected between 1993 and 2016 CE at the DE08-2, DSSW19K, DSSW20K, South Pole, Aurora Basin North (ABN), and Lock-In sites (and one previously published firn CO dataset at Berkner) were used to reconstruct the atmospheric history of CO from ∼1897 CE, using inverse modeling that incorporates the influence of gas transport in firn. Excellent consistency was observed between the youngest ice core gas [CO] and the [CO] from the base of the firn and between the recent firn [CO] and atmospheric [CO] measurements at Mawson station (eastern Antarctica), yielding a consistent and contiguous record of CO across these different archives. Our Antarctic [CO] record is relatively stable from −835 to 1500 CE, with mixing ratios within a 30–45 ppb range (2σ). There is a ∼5 ppb decrease in [CO] to a minimum at around 1700 CE during the Little Ice Age. CO mixing ratios then increase over time to reach a maximum of ∼54 ppb by ∼1985 CE. Most of the industrial period [CO] growth occurred between about 1940 to 1985 CE, after which there was an overall [CO] decrease, as observed in Greenland firn air and later at atmospheric monitoring sites and attributed partly to reduced CO emissions from combustion sources. Our Antarctic ice core gas CO observations differ from previously published records in two key aspects. First, our mixing ratios are significantly lower than reported previously, suggesting that previous studies underestimated blank contributions. Second, our new CO record does not show a maximum in the late 1800s. The absence of a [CO] peak around the turn of the century argues against there being a peak in Southern Hemisphere biomass burning at this time, which is in agreement with (i) other paleofire proxies such as ethane or acetylene and (ii) conclusions reached by paleofire modeling. The combined ice core and firn air [CO] history, spanning −835 to 1992 CE, extended to the present by the Mawson atmospheric record, provides a useful benchmark for future atmospheric chemistry modeling studies. International audience
Mémoires en Sciences... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsCopenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert Mémoires en Sciences... arrow_drop_down Copernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsCopenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2023-9&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Other literature type , Article , Preprint 2023 FrancePublisher:Copernicus GmbH E. Queiroz Alves; E. Queiroz Alves; W. Wong; W. Wong; W. Wong; J. Hefter; H. Grotheer; H. Grotheer; T. Tesi; T. Gentz; K. Zonneveld; G. Mollenhauer; G. Mollenhauer; G. Mollenhauer;The last deglaciation is the most recent relatively well-documented period of pronounced and fast climate warming, and, as such, it holds important information for our understanding of the climate system. Notably, while research into terrestrial organic carbon reservoirs has been instrumental in exploring the possible sources of atmospheric carbon dioxide during periods of rapid change, the underlying mechanisms are not fully understood. Here we investigate the mobilization of organic matter to the Bay of Biscay, located in the north-eastern Atlantic Ocean off the coasts of France and Spain. Specifically, we focus on the area that was the mouth of the Channel River during the last deglaciation, where an enhanced terrigenous input has been reported for the last glacial–interglacial transition. We conducted a comprehensive suite of biomarker analyses (e.g. n-alkanes, hopanes and n-alkanoic acids) and isotopic investigations (radiocarbon dating and δ13C measurements) on a high-resolution sedimentary archive. The present study provides the first direct evidence for the fluvial supply of immature and ancient terrestrial organic matter to the core location. Moreover, our results reveal the possibility of permafrost carbon export to the ocean, driven by processes such as deglacial warming and glacial erosion. These findings are consistent with observations from other regions characterized by present or past permafrost conditions on land, which have shown that permafrost thaw and glacial erosion can lead to carbon remobilization, potentially influencing atmospheric carbon dioxide levels.
ArchiMer - Instituti... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert ArchiMer - Instituti... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2024Data sources: Copernicus Publicationshttps://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2023 Netherlands, Spain, FrancePublisher:Copernicus GmbH Funded by:NWO | TRIGGER – Tracing the Reg..., EC | OceaNiceNWO| TRIGGER – Tracing the Regional Initiator of the Great Global Eocene plate Reorganization ,EC| OceaNiceF. S. Hoem; A. López-Quirós; A. López-Quirós; S. van de Lagemaat; J. Etourneau; J. Etourneau; M.-A. Sicre; C. Escutia; H. Brinkhuis; H. Brinkhuis; F. Peterse; F. Sangiorgi; P. K. Bijl;handle: 10261/344893
At present, a strong latitudinal sea-surface-temperature (SST) gradient of g1/4g€¯16g€¯g exists across the Southern Ocean, maintained by the Antarctic Circumpolar Current (ACC) and a set of complex frontal systems. Together with the Antarctic ice masses, this system has formed one of the most important global climate regulators. The timing of the onset of the ACC system, its development towards modern-day strength and the consequences for the latitudinal SST gradient around the southern Atlantic Ocean are still uncertain. Here we present new TEX86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms)-derived SST records from two sites located east of Drake Passage (south-western South Atlantic) to assist in better understanding two critical time intervals of prominent climate transitions during the Cenozoic: the late Eocene-early Oligocene (Ocean Drilling Program, ODP, Site 696) and Middle-Late Miocene (IODP Site U1536) transitions. Our results show temperate conditions (20-11g€¯g) during the first time interval, with a weaker latitudinal SST gradient (g1/4g€¯8g€¯g) across the Atlantic sector of the Southern Ocean compared to present day. We ascribe the similarity in SSTs between Sites 696 and 511 in the late Eocene-early Oligocene South Atlantic to a persistent, strong subpolar gyre circulation connecting the sites, which can only exist in the absence of a strong throughflow across the Drake Passage. Surprisingly, the southern South Atlantic record Site 696 shows comparable SSTs (g1/4g€¯12-14g€¯g) during both the earliest Oligocene oxygen isotope step (EOIS, g1/4g€¯33.65g€¯Ma) and the Miocene Climatic Optimum (MCO, g1/4g€¯16.5g€¯Ma). Apparently, maximum Oligocene Antarctic ice volume could coexist with warm ice-proximal surface ocean conditions, while at similar ocean temperatures, the Middle Miocene Antarctic ice sheet was likely reduced. Only a few Middle-Late Miocene (discontinuous) high-latitude records exist due to ice advances causing unconformities. Our low-resolution Site U1536 record of southern South Atlantic SSTs cooled to g1/4g€¯5g€¯g during the Middle Miocene Climate Transition (MMCT, 14g€¯Ma), making it the coldest oceanic region in the poorly recorded Antarctic realm and likely the main location for deep-water formation. The already-cold south-western South Atlantic conditions at the MMCT with relatively moderate additional cooling during the Late Miocene contrasts with the profound cooling in the lower latitudes and other sectors of the Southern Ocean due to northward expansion of the Southern Ocean frontal systems. This work used International Ocean Discovery Program (IODP) archived samples and data. We thank the great scientists and crew on Expedition 382, who also helped with data interpretation and discussions of results from Site U1536. We thank Mariska Hoorweg for technical support at the Utrecht University GeoLab. Frida S. Hoem and Peter K. Bijl acknowledge funding from the ERC starting grant 802835 “OceanNice”. Carlota Escutia and Adrián López-Quirós acknowledge funding provided by the Spanish Ministry of Science and Innovation (grants CTM2014-60451-C2-1/2-P and CTM2017-89711-C2-1/2-P, co-funded by the European Union through FEDER funds) and JUAN DE LA CIERVA-TRAINING AID 2021 (FJC2021-047046-I, MCIN/AEI/10.13039/501100011033 and NextGenerationEU/PRTR). Suzanna van de Lagemaat acknowledges funding by NWO Vici (grant no. 865.17.001) awarded to Douwe van Hinsbergen. This research has been supported by the Dutch Research Council (NWO) Polar Programme (grant no. ALW.2016.001).
Climate of the Past ... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsHAL Descartes; Mémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYFull-Text: https://hal.science/hal-04283114/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsHAL Descartes; Mémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYFull-Text: https://hal.science/hal-04283114/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint , Other literature type , Article 2023 FrancePublisher:Copernicus GmbH Funded by:FCT | LA 1, UKRI | Live Automated Materials ...FCT| LA 1 ,UKRI| Live Automated Materials Plan (LAMP)P. Meister; A. Alexandre; H. Bailey; P. Barker; B. K. Biskaborn; E. Broadman; R. Cartier; R. Cartier; B. Chapligin; M. Couapel; J. R. Dean; B. Diekmann; B. Diekmann; P. Harding; P. Harding; A. C. G. Henderson; A. Hernandez; U. Herzschuh; U. Herzschuh; U. Herzschuh; S. S. Kostrova; J. Lacey; M. J. Leng; M. J. Leng; A. Lücke; A. W. Mackay; E. K. Magyari; B. Narancic; B. Narancic; C. Porchier; G. Rosqvist; A. Shemesh; C. Sonzogni; G. E. A. Swann; F. Sylvestre; H. Meyer;Oxygen isotopes in biogenic silica (δ18OBSi) from lake sediments allow for quantitative reconstruction of past hydroclimate and proxy–model comparison in terrestrial environments. The signals of individual records have been attributed to different factors, such as air temperature (Tair), atmospheric circulation patterns, hydrological changes and lake evaporation. While every lake will have its own set of drivers of d18O, here we explore the extent to which regional or even global signals emerge from a series of palaeoenvironmental records. For this purpose, we have identified and compiled 71 down–core records published to date and complemented these datasets with additional lake basin parameters (e.g. lake water residence time and catchment size) to best characterize the signal properties. Records feature widely different temporal coverage and resolution ranging from decadal–scale records covering the last 150 years to records with multi–millennial scale resolution spanning glacial–interglacial cycles. Best coverage in number of records (N = 37) and datapoints (N = 2112) is available for northern hemispheric (NH) extra–tropic regions throughout the Holocene (corresponding to Marine Isotope Stage 1; MIS 1). To address the different variabilities and temporal offsets, records were brought to a common temporal resolution by binning and subsequently filtered for hydrologically open lakes with lake water residence times 45° N) lakes, we find common δ18OBSi patterns during both the Holocene and the Common Era and maxima and minima corresponding to known climate episodes such as the Holocene Thermal Maximum (HTM), Neoglacial Cooling, Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). These patterns are in line with long–term Tair changes supported by previously published climate reconstructions from other archives as well as Holocene summer insolation changes. In conclusion, oxygen isotope records from NH extratopic lake sediments feature a common climate signal at centennial (for CE) and millennial (for Holocene) time scales despite stemming from different lakes in different geographic locations and constitute a valuable proxy for past climate reconstructions. International audience
https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefMémoires en Sciences de l'Information et de la Communication; HAL AMU; HAL-IRDPreprint . 2023License: CC BYFull-Text: https://hal.science/hal-04304267/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routeshybrid 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!more_vert https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/cp-202...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefMémoires en Sciences de l'Information et de la Communication; HAL AMU; HAL-IRDPreprint . 2023License: CC BYFull-Text: https://hal.science/hal-04304267/documentadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-96&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Preprint , Other literature type , Article 2023 FrancePublisher:Copernicus GmbH L. Su; L. Su; J. Ren; M.-A. Sicre; Y. Bai; R. Zhao; R. Zhao; X. Han; Z. Li; H. Jin; H. Jin; A. S. Astakhov; X. Shi; J. Chen; J. Chen;Decreasing sea ice extent caused by climate change is affecting the carbon cycle of the Arctic Ocean. In this study, surface sediments across the western Arctic Ocean are investigated to characterize sources of sedimentary organic carbon (OC). Bulk organic parameters (total organic carbon, total nitrogen, δ13Corg, and δ15N) and molecular organic biomarkers (e.g., sterols and highly branched isoprenoids - HBIs) are combined to distinguish between sympagic, pelagic, and terrestrial OC sources. Their downcore profiles generated at the Chukchi Sea R1 core site (74∘ N) are then used to evaluate changes in the relative contribution of these components of sedimentary OC over the last 200 years with decreasing sea ice. Our data evidence that, from the 1820s to the 1930s, prevailing high sea ice cover inhibited in situ primary production, resulting in prominent land-derived material in sediments. Then, from the 1930s to the 1980s, primary production started increasing with the gradual decline of summer sea ice. The ratio of sympagic and pelagic OC began to rise to account for the larger portion of sedimentary OC. Since the 1980s, accelerated sea ice loss led to enhanced primary production, stabilizing over the last decades due to freshwater-induced surface ocean stratification in summer. International audience
https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsMémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert https://doi.org/10.5... arrow_drop_down https://doi.org/10.5194/egusph...Preprint . 2023 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsMémoires en Sciences de l'Information et de la Communication; HAL-CEA; HAL-IRDArticle . 2023License: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2023-64&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 FrancePublisher:Copernicus GmbH Julia Rieke Hagemann; Lester Lembke-Jene; Frank Lamy; Maria-Elena Vorrath; Jérôme Kaiser; Juliane Müller; Helge W. Arz; Jens Hefter; Andrea Jaeschke; Nicoletta Ruggieri; Ralf Tiedemann;As remnants of living organisms, alkenones and isoprenoid glycerol dialkyl glycerol tetraether lipids (isoGDGTs) are widely used biomarkers for determining ocean water temperatures from the past. The organisms that these proxy carriers stem from are influenced by a number of environmental parameters, such as water depth, nutrient availability, light conditions, or seasonality, which all may significantly bias the calibration to ambient water temperatures. Reliable temperature determinations thus remain challenging, especially in higher latitudes and for undersampled regions. We analyzed 33 sediment surface samples from the southern Chilean continental margin and the Drake Passage for alkenones and isoGDGTs and compared the results with gridded instrumental reference data from the World Ocean Atlas 2005 (WOA05) and previously published data from an extended study area covering the central and western South Pacific towards the Aotearoa / New Zealand continental margin. We show that for alkenone-derived sea surface temperatures (SSTs), the widely used global core-top calibration of Müller et al. (1998) yields the smallest deviation of the WOA05-based SSTs. On the contrary, the calibration of Sikes et al. (1997), determined for higher latitudes and summer SSTs, overestimates modern WOA05-based SSTs in both the annual mean and summer. Our alkenone SSTs show a slight seasonal shift of ∼ 1 ∘C at the southern Chilean margin and up to ∼ 2 ∘C in the Drake Passage towards austral summer SSTs. Samples in the central South Pacific, on the other hand, reflect an annual mean signal. We show that for isoGDGT-based temperatures, the subsurface calibration of Kim et al. (2012a) best reflects temperatures from the WOA05 in areas north of the Subantarctic Front (SAF). Temperatures south of the SAF are, in contrast, significantly overestimated by up to 14 ∘C, irrespective of the applied calibration. In addition, we used the GDGT [2]/[3] ratios, which give an indication of the production depth of the isoGDGTs and/or potential influences from land. Our samples reflect a subsurface (0–200 m water depth) rather than a surface (0–50 m water depth) signal in the entire study area and show a correlation with the monthly dust distribution in the South Pacific, indicating terrigenous influences. The overestimation of isoGDGT surface and subsurface temperatures south of the SAF highlights the need for a reassessment of existing calibrations in the polar Southern Ocean. Therefore, we suggest a modified Southern Ocean tetraether index (TEX86)-based calibration for surface and subsurface temperatures, which shows a lower temperature sensitivity and yields principally lower absolute temperatures, which align more closely with WOA05-derived values and also OH–isoGDGT-derived temperatures.
Climate of the Past ... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/egusph...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!more_vert Climate of the Past ... arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus Publicationshttps://doi.org/10.5194/egusph...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/egusphere-2022-1456&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 Switzerland, France, DenmarkPublisher:Copernicus GmbH A. P. M. Servettaz; A. P. M. Servettaz; A. J. Orsi; A. J. Orsi; M. A. J. Curran; M. A. J. Curran; A. D. Moy; A. D. Moy; A. Landais; J. R. McConnell; T. J. Popp; E. Le Meur; X. Faïn; J. Chappellaz; J. Chappellaz;The temperature of the Earth is one of the most important climate parameters. Proxy records of past climate changes, in particular temperature, represent a fundamental tool for exploring internal climate processes and natural climate forcings. Despite the excellent information provided by ice core records in Antarctica, the temperature variability of the past 2000 years is difficult to evaluate from the low-accumulation sites in the Antarctic continent interior. Here we present the results from the Aurora Basin North (ABN) ice core (71∘ S, 111∘ E, 2690 m a.s.l.) in the lower part of the East Antarctic plateau, where accumulation is substantially higher than other ice core drilling sites on the plateau, and provide unprecedented insight into East Antarctic past temperature variability. We reconstructed the temperature of the last 2000 years using two independent methods: the widely used water stable isotopes (δ18O) and by inverse modelling of borehole temperature and past temperature gradients estimated from the inert gas stable isotopes (δ40Ar and δ15N). This second reconstruction is based on three independent measurement types: borehole temperature, firn thickness, and firn temperature gradient. The δ18O temperature reconstruction supports stable temperature conditions within 1 ∘C over the past 2000 years, in agreement with other ice core δ18O records in the region. However, the gas and borehole temperature reconstruction suggests that surface conditions 2 ∘C cooler than average prevailed in the 1000–1400 CE period and supports a 20th century warming of 1 ∘C. A precipitation hiatus during cold periods could explain why water isotope temperature reconstruction underestimates the temperature changes. Both reconstructions arguably record climate in their own way, with a focus on atmospheric and hydrologic cycles for water isotopes, as opposed to surface temperature for gas isotopes and boreholes. This study demonstrates the importance of using a variety of sources for comprehensive paleoclimate reconstructions. International audience
Mémoires en Sciences... arrow_drop_down Copenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-91&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesgold 3 citations 3 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert Mémoires en Sciences... arrow_drop_down Copenhagen University Research Information SystemArticle . 2023Data sources: Copenhagen University Research Information Systemhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsInfoscience - EPFL scientific publicationsArticleData sources: Infoscience - EPFL scientific publicationsadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-91&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article , Other literature type , Preprint 2022 France, Portugal, NorwayPublisher:Copernicus GmbH Funded by:EC | ACCLIMATE, EC | ICE2ICEEC| ACCLIMATE ,EC| ICE2ICEC. Waelbroeck; J. Tjiputra; C. Guo; K. H. Nisancioglu; E. Jansen; E. Jansen; N. Vázquez Riveiros; S. Toucanne; F. Eynaud; L. Rossignol; F. Dewilde; E. Marchès; S. Lebreiro; S. Nave;handle: 10400.9/4144 , 11250/3074362
Abstract. We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry in order to interpret the observed Cibicides δ13C changes at the stadial–interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides δ13C observed at the end of HS4 between ∼2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high-latitude glacial North Atlantic. Our model results show that this Cibicides δ13C signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep-water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from ∼40 % at 2000 m to ∼80 % at 4000 m. Below ∼4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials compared to during interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies. International audience
HAL-CEA; HAL-IRD arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of Ifremerhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsBergen Open Research Archive - UiB; Norwegian Open Research ArchivesArticle . 2023 . Peer-reviewedLicense: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-83&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!visibility 17visibility views 17 download downloads 6 Powered bymore_vert HAL-CEA; HAL-IRD arrow_drop_down ArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of IfremerArchiMer - Institutional Archive of IfremerOther literature type . 2023Data sources: ArchiMer - Institutional Archive of Ifremerhttps://doi.org/10.5194/cp-202...Preprint . 2022 . Peer-reviewedLicense: CC BYData sources: CrossrefCopernicus Publications; Climate of the Past (CP)Other literature type . 2023Data sources: Copernicus PublicationsBergen Open Research Archive - UiB; Norwegian Open Research ArchivesArticle . 2023 . Peer-reviewedLicense: CC BYadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.5194/cp-2022-83&type=result"></script>'); --> </script>
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