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- Climate signals in stable carbon and hydrogen isotopes of lignin methoxy
groups from southern German beech trees Abstract: Climate signals in stable carbon and hydrogen isotopes of lignin methoxy groups from southern German beech trees Anna Wieland, Markus Greule, Philipp Roemer, Jan Esper, and Frank Keppler Clim. Past, 18, 1849–1866, https://doi.org/10.5194/cp-18-1849-2022, 2022 We examined annually resolved stable carbon and hydrogen isotope ratios of wood lignin methoxy groups of beech trees growing in temperate, low elevation environments. Here, carbon isotope ratios reveal highest correlations with regional summer temperatures while hydrogen isotope ratios correlate more strongly with large-scale temperature changes. By combining the dual isotope ratios of wood lignin methoxy groups, a proxy for regional- to subcontinental-scale temperature patterns can be applied. PubDate: Mon, 15 Aug 2022 11:21:20 +020 DOI: 10.5194/cp-18-1849-2022 2022
- Compilation of Southern Ocean sea-ice records covering the last
glacial-interglacial cycle (12–130 ka) Abstract: Compilation of Southern Ocean sea-ice records covering the last glacial-interglacial cycle (12–130 ka) Matthew Chadwick, Xavier Crosta, Oliver Esper, Lena Thöle, and Karen E. Kohfeld Clim. Past, 18, 1815–1829, https://doi.org/10.5194/cp-18-1815-2022, 2022 Algae preserved in seafloor sediments have allowed us to reconstruct how Antarctic sea ice has varied between cold and warm time periods in the last 130 000 years. The patterns and timings of sea-ice increase and decrease vary between different parts of the Southern Ocean. Sea ice is most sensitive to changing climate at the external edges of Southern Ocean gyres (large areas of rotating ocean currents). PubDate: Wed, 10 Aug 2022 16:18:07 +020 DOI: 10.5194/cp-18-1815-2022 2022
- The ST22 chronology for the Skytrain Ice Rise ice core – Part 1: A
stratigraphic chronology of the last 2000 years Abstract: The ST22 chronology for the Skytrain Ice Rise ice core – Part 1: A stratigraphic chronology of the last 2000 years Helene M. Hoffmann, Mackenzie M. Grieman, Amy C. F. King, Jenna A. Epifanio, Kaden Martin, Diana Vladimirova, Helena V. Pryer, Emily Doyle, Axel Schmidt, Jack D. Humby, Isobel F. Rowell, Christoph Nehrbass-Ahles, Elizabeth R. Thomas, Robert Mulvaney, and Eric W. Wolff Clim. Past, 18, 1831–1847, https://doi.org/10.5194/cp-18-1831-2022, 2022 The WACSWAIN project (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) investigates the fate of the West Antarctic Ice Sheet during the last warm period on Earth (115 000–130 000 years before present). Within this framework an ice core was recently drilled at Skytrain Ice Rise. In this study we present a stratigraphic chronology of that ice core based on absolute age markers and annual layer counting for the last 2000 years. PubDate: Wed, 10 Aug 2022 16:18:07 +020 DOI: 10.5194/cp-18-1831-2022 2022
- Bottom water oxygenation changes in the southwestern Indian Ocean as an
indicator for enhanced respired carbon storage since the last glacial inception Abstract: Bottom water oxygenation changes in the southwestern Indian Ocean as an indicator for enhanced respired carbon storage since the last glacial inception Helen Eri Amsler, Lena Mareike Thöle, Ingrid Stimac, Walter Geibert, Minoru Ikehara, Gerhard Kuhn, Oliver Esper, and Samuel Laurent Jaccard Clim. Past, 18, 1797–1813, https://doi.org/10.5194/cp-18-1797-2022, 2022 We present sedimentary redox-sensitive trace metal records from five sediment cores retrieved from the SW Indian Ocean. These records are indicative of oxygen-depleted conditions during cold periods and enhanced oxygenation during interstadials. Our results thus suggest that deep-ocean oxygenation changes were mainly controlled by ocean ventilation and that a generally more sluggish circulation contributed to sequestering remineralized carbon away from the atmosphere during glacial periods. PubDate: Tue, 09 Aug 2022 16:18:07 +020 DOI: 10.5194/cp-18-1797-2022 2022
- Quantifying the contribution of forcing and three prominent modes of
variability on historical climate Abstract: Quantifying the contribution of forcing and three prominent modes of variability on historical climate Andrew P. Schurer, Gabriele C. Hegerl, Hugues Goosse, Massimo A. Bollasina, Matthew H. England, Michael J. Mineter, Doug M. Smith, and Simon F. B. Tett Clim. Past Discuss., https//doi.org/10.5194/cp-2022-55,2022 Preprint under review for CP (discussion: open, 0 comments) We adopt an existing data assimilation technique to constrain a model simulation to follow three important modes of variability, the North Atlantic Oscillation, El-Niño Southern Oscillation and the Southern Annular Model. How it compares to the observed climate is evaluated, with improvements over simulations without data-assimilation found over many regions, in particular the tropics, north Atlantic and Europe and discrepancies with global cooling following volcanic eruptions are reconciled. PubDate: Tue, 09 Aug 2022 16:18:07 +020 DOI: 10.5194/cp-2022-552022
- Changes in productivity and intermediate circulation in the northern
Indian Ocean since the last deglaciation: new insights from benthic foraminiferal Cd ∕ Ca records and benthic assemblage analyses Abstract: Changes in productivity and intermediate circulation in the northern Indian Ocean since the last deglaciation: new insights from benthic foraminiferal Cd ∕ Ca records and benthic assemblage analyses Ruifang Ma, Sophie Sépulcre, Laetitia Licari, Frédéric Haurine, Franck Bassinot, Zhaojie Yu, and Christophe Colin Clim. Past, 18, 1757–1774, https://doi.org/10.5194/cp-18-1757-2022, 2022 We provide high-resolution Cd / Ca records of benthic foraminifera on two cores from the northern Indian Ocean since the last deglaciation. We reconstructed intermediate Cdw records based on Cd / Ca. Combined with benthic foraminiferal assemblages, we show that intermediate Cdw during the last deglaciation was mainly influenced by the ventilation of intermediate–bottom water masses. Thereafter during the Holocene surface productivity is the main forcing factor related to monsoon precipitation. PubDate: Wed, 03 Aug 2022 16:51:51 +020 DOI: 10.5194/cp-18-1757-2022 2022
- Extreme historical droughts and floods in the Hanjiang River Basin, China,
since 1426 Abstract: Extreme historical droughts and floods in the Hanjiang River Basin, China, since 1426 Xiaodan Zhang, Guoyu Ren, Yuda Yang, He Bing, Zhixin Hao, and Panfeng Zhang Clim. Past, 18, 1775–1796, https://doi.org/10.5194/cp-18-1775-2022, 2022 Applying yearly drought and flood records from historical documents and precipitation data in the period of instrumental measurements, this study constructs a time series of extreme droughts and floods in the Hanjiang River Basin from 1426–2017 and analyzes the temporal and spatial characteristics of the extreme drought and flood event variations. PubDate: Wed, 03 Aug 2022 16:51:51 +020 DOI: 10.5194/cp-18-1775-2022 2022
- Antarctic sea ice over the past 130 000 years – Part 1: a review of
what proxy records tell us Abstract: Antarctic sea ice over the past 130 000 years – Part 1: a review of what proxy records tell us Xavier Crosta, Karen E. Kohfeld, Helen C. Bostock, Matthew Chadwick, Alice Du Vivier, Oliver Esper, Johan Etourneau, Jacob Jones, Amy Leventer, Juliane Müller, Rachael H. Rhodes, Claire S. Allen, Pooja Ghadi, Nele Lamping, Carina B. Lange, Kelly-Anne Lawler, David Lund, Alice Marzocchi, Katrin J. Meissner, Laurie Menviel, Abhilash Nair, Molly Patterson, Jennifer Pike, Joseph G. Prebble, Christina Riesselman, Henrik Sadatzki, Louise C. Sime, Sunil K. Shukla, Lena Thöle, Maria-Elena Vorrath, Wenshen Xiao, and Jiao Yang Clim. Past, 18, 1729–1756, https://doi.org/10.5194/cp-18-1729-2022, 2022 Despite its importance in the global climate, our knowledge of Antarctic sea-ice changes throughout the last glacial–interglacial cycle is extremely limited. As part of the Cycles of Sea Ice Dynamics in the Earth system (C-SIDE) Working Group, we review marine- and ice-core-based sea-ice proxies to provide insights into their applicability and limitations. By compiling published records, we provide information on Antarctic sea-ice dynamics over the past 130 000 years. PubDate: Tue, 02 Aug 2022 16:51:51 +020 DOI: 10.5194/cp-18-1729-2022 2022
- Climate changes during the Lateglacial in South Europe: new insights based
on pollen and brGDGTs of Lake Matese in Italy Abstract: Climate changes during the Lateglacial in South Europe: new insights based on pollen and brGDGTs of Lake Matese in Italy Mary Robles, Odile Peyron, Guillemette Ménot, Elisabetta Brugiapaglia, Sabine Wulf, Oona Appelt, Marion Blache, Boris Vannière, Lucas Dugerdil, Bruno Paura, Salomé Ansanay-Alex, Amy Cromartie, Laurent Charlet, Stephane Guédron, Jacques-Louis de Beaulieu, and Sébastien Joannin Clim. Past Discuss., https//doi.org/10.5194/cp-2022-54,2022 Preprint under review for CP (discussion: open, 0 comments) Quantitative climate reconstructions based on pollen and brGDGTs reveal, for the Lateglacial, a warm Bølling–Allerød and a marked cold Younger Dryas in Italy, showing no latitudinal differences in terms of temperatures across Italy. In terms of precipitation, no latitudinal differences are recorded during the Bølling–Allerød whereas the latitudes 40–42° N appear as a key junction point between wetter conditions in Southern Italy and drier conditions in Northern Italy during the Younger Dryas. PubDate: Thu, 28 Jul 2022 16:07:21 +020 DOI: 10.5194/cp-2022-542022
- Regional validation of the use of diatoms in ice cores from the Antarctic
Peninsula as a Southern Hemisphere westerly wind proxy Abstract: Regional validation of the use of diatoms in ice cores from the Antarctic Peninsula as a Southern Hemisphere westerly wind proxy Dieter R. Tetzner, Elizabeth R. Thomas, Claire S. Allen, and Mackenzie M. Grieman Clim. Past, 18, 1709–1727, https://doi.org/10.5194/cp-18-1709-2022, 2022 Changes in the Southern Hemisphere westerly winds are drivers of recent environmental changes in West Antarctica. However, our understanding of this relationship is limited by short and sparse observational records. Here we present the first regional wind study based on the novel use of diatoms preserved in Antarctic ice cores. Our results demonstrate that diatom abundance is the optimal record for reconstructing wind strength variability over the Southern Hemisphere westerly wind belt. PubDate: Thu, 21 Jul 2022 10:48:34 +020 DOI: 10.5194/cp-18-1709-2022 2022
- Subdaily meteorological measurements of temperature, direction of the
movement of the clouds, and cloud cover in the Late Maunder Minimum by Louis Morin in Paris Abstract: Subdaily meteorological measurements of temperature, direction of the movement of the clouds, and cloud cover in the Late Maunder Minimum by Louis Morin in Paris Thomas Pliemon, Ulrich Foelsche, Christian Rohr, and Christian Pfister Clim. Past, 18, 1685–1707, https://doi.org/10.5194/cp-18-1685-2022, 2022 We have digitized and analyzed meteorological variables (temperature, direction of the movement of the clouds, and cloud cover), which were noted by Louis Morin in the period 1665–1713 in Paris. This time period is characterized by cold winters and autumns and moderate springs and summers. A low frequency of westerlies in the winter months leads to a cooling. Morin's measurements seem to be trustworthy. Only cloud cover in quantitative terms should be taken with caution. PubDate: Thu, 21 Jul 2022 10:48:34 +020 DOI: 10.5194/cp-18-1685-2022 2022
- Greenhouse gases modulate the strength of millennial-scale subtropical
rainfall, consistent with future predictions Abstract: Greenhouse gases modulate the strength of millennial-scale subtropical rainfall, consistent with future predictions Fei Guo, Steven Clemens, Yuming Liu, Ting Wang, Huimin Fan, Xingxing Liu, and Youbin Sun Clim. Past, 18, 1675–1684, https://doi.org/10.5194/cp-18-1675-2022, 2022 Our high-resolution loess Ca/Ti record displays millennial monsoon oscillations that persist over the last 650 kyr. Wavelet results indicate the ice volume and GHG co-modulation at the 100 kyr band and GHG and local insolation forcing at the precession band for the magnitude of millennial monsoon variability of loess Ca/Ti. The inferred mechanism calls on dynamic linkages to variability in AMOC. At the precession band, combined effects of GHG and insolation lead to increased extreme rainfall. PubDate: Wed, 20 Jul 2022 10:48:34 +020 DOI: 10.5194/cp-18-1675-2022 2022
- Seasonal aridity in the Indo-Pacific Warm Pool during the Late Glacial
driven by El Niño-like conditions Abstract: Seasonal aridity in the Indo-Pacific Warm Pool during the Late Glacial driven by El Niño-like conditions Petter L. Hällberg, Frederik Schenk, Kweku A. Yamoah, Xueyuen Kuang, and Rienk H. Smittenberg Clim. Past, 18, 1655–1674, https://doi.org/10.5194/cp-18-1655-2022, 2022 Using climate model simulations, we find that SE Asian tropical climate was strongly seasonal under Late Glacial conditions. During Northern Hemisphere winters, it was highly arid in this region that is today humid year-round. The seasonal aridity was driven by orbital forcing and stronger East Asian winter monsoon. A breakdown of deep convection caused a reorganized Walker Circulation and a mean state resembling El Niño conditions. PubDate: Mon, 18 Jul 2022 18:08:07 +020 DOI: 10.5194/cp-18-1655-2022 2022
- Investigating stable oxygen and carbon isotopic variability in speleothem
records over the last millennium using multiple isotope-enabled climate models Abstract: Investigating stable oxygen and carbon isotopic variability in speleothem records over the last millennium using multiple isotope-enabled climate models Janica C. Bühler, Josefine Axelsson, Franziska A. Lechleitner, Jens Fohlmeister, Allegra N. LeGrande, Madhavan Midhun, Jesper Sjolte, Martin Werner, Kei Yoshimura, and Kira Rehfeld Clim. Past, 18, 1625–1654, https://doi.org/10.5194/cp-18-1625-2022, 2022 We collected and standardized the output of five isotope-enabled simulations for the last millennium and assess differences and similarities to records from a global speleothem database. Modeled isotope variations mostly arise from temperature differences. While lower-resolution speleothems do not capture extreme changes to the extent of models, they show higher variability on multi-decadal timescales. As no model excels in all comparisons, we advise a multi-model approach where possible. PubDate: Wed, 13 Jul 2022 18:08:07 +020 DOI: 10.5194/cp-18-1625-2022 2022
- Was there a volcanic-induced long-lasting cooling over the Northern
Hemisphere in the mid-6th–7th century' Abstract: Was there a volcanic-induced long-lasting cooling over the Northern Hemisphere in the mid-6th–7th century' Evelien van Dijk, Johann Jungclaus, Stephan Lorenz, Claudia Timmreck, and Kirstin Krüger Clim. Past, 18, 1601–1623, https://doi.org/10.5194/cp-18-1601-2022, 2022 A double volcanic eruption in 536 and 540 CE caused one of the coldest decades during the last 2000 years. We analyzed new climate model simulations from that period and found a cooling of up to 2°C and a sea-ice extent up to 200 km further south. Complex interactions between sea ice and ocean circulation lead to a reduction in the northward ocean heat transport, which makes the sea ice extend further south; this in turn leads to a surface cooling up to 20 years after the eruptions. PubDate: Tue, 12 Jul 2022 22:59:23 +020 DOI: 10.5194/cp-18-1601-2022 2022
- The role of ice-sheet topography in the Alpine hydro-climate at glacial
times Abstract: The role of ice-sheet topography in the Alpine hydro-climate at glacial times Patricio Velasquez, Martina Messmer, and Christoph C. Raible Clim. Past, 18, 1579–1600, https://doi.org/10.5194/cp-18-1579-2022, 2022 We investigate the sensitivity of the glacial Alpine hydro-climate to northern hemispheric and local ice-sheet changes. We perform sensitivity simulations of up to 2 km horizontal resolution over the Alps for glacial periods. The findings demonstrate that northern hemispheric and local ice-sheet topography are important role in regulating the Alpine hydro-climate and permits a better understanding of the Alpine precipitation patterns at glacial times. PubDate: Mon, 11 Jul 2022 22:59:23 +020 DOI: 10.5194/cp-18-1579-2022 2022
- Stratigraphic templates for ice core records of the past 1.5 Myr
Abstract: Stratigraphic templates for ice core records of the past 1.5 Myr Eric W. Wolff, Hubertus Fischer, Tas van Ommen, and David A. Hodell Clim. Past, 18, 1563–1577, https://doi.org/10.5194/cp-18-1563-2022, 2022 Projects are underway to drill ice cores in Antarctica reaching 1.5 Myr back in time. Dating such cores will be challenging. One method is to match records from the new core against datasets from existing marine sediment cores. Here we explore the options for doing this and assess how well the ice and marine records match over the existing 800 000-year time period. We are able to recommend a strategy for using marine data to place an age scale on the new ice cores. PubDate: Thu, 07 Jul 2022 22:59:23 +020 DOI: 10.5194/cp-18-1563-2022 2022
- On the economic impact of droughts in central Europe: the decade from 1531
to 1540 from the Polish perspective Abstract: On the economic impact of droughts in central Europe: the decade from 1531 to 1540 from the Polish perspective Tomasz Związek, Piotr Guzowski, Radosław Poniat, Maciej T. Radomski, Monika Kozłowska-Szyc, Tomasz Panecki, Sandra Słowińska, Bogusława Kruczkowska, Michał Targowski, and Dagmara Adamska Clim. Past, 18, 1541–1561, https://doi.org/10.5194/cp-18-1541-2022, 2022 We wanted to take an in-depth look at how climate events affected the economy of early modern Poland. We focused on analysing all available sources of a fiscal nature for this period. In addition, we analysed available materials on the export of primary agricultural products. Our results have shown that the economic system in Poland at that time coped effectively with periodic droughts, and it was only the great drought of 1540 that significantly shook the state's economy. PubDate: Tue, 05 Jul 2022 17:46:50 +020 DOI: 10.5194/cp-18-1541-2022 2022
- Development of longitudinal dunes under Pangaean atmospheric circulation
Abstract: Development of longitudinal dunes under Pangaean atmospheric circulation Hiroki Shozaki and Hitoshi Hasegawa Clim. Past, 18, 1529–1539, https://doi.org/10.5194/cp-18-1529-2022, 2022 Atmospheric circulation in the supercontinent of Pangaea is thought to have been significantly different from today. We present the spatial distribution of palaeowind directions recorded in Lower Jurassic aeolian sandstones in the western US. This reveals the development of longitudinal dunes formed by a combination of westerly, northwesterly, and northeasterly palaeowinds. The reconstructed palaeowind pattern at ~19–27°N is consistent with the model-generated surface wind pattern in Pangaea. PubDate: Tue, 05 Jul 2022 17:46:50 +020 DOI: 10.5194/cp-18-1529-2022 2022
- Influence of long-term changes in solar irradiance forcing on the Southern
Annular Mode Abstract: Influence of long-term changes in solar irradiance forcing on the Southern Annular Mode Nicky M. Wright, Claire E. Krause, Steven J. Phipps, Ghyslaine Boschat, and Nerilie J. Abram Clim. Past, 18, 1509–1528, https://doi.org/10.5194/cp-18-1509-2022, 2022 The Southern Annular Mode (SAM) is a major mode of climate variability. Proxy-based SAM reconstructions show changes that last millennium climate simulations do not reproduce. We test the SAM's sensitivity to solar forcing using simulations with a range of solar values and transient last millennium simulations with large-amplitude solar variations. We find that solar forcing can alter the SAM and that strong solar forcing transient simulations better match proxy-based reconstructions. PubDate: Fri, 01 Jul 2022 15:43:36 +020 DOI: 10.5194/cp-18-1509-2022 2022
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