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- Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in
South Africa
Abstract: Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa
Jenny Maccali, Anna Nele Meckler, Stein-Erik Lauritzen, Torill Brekken, Helen Aase Rokkan, Alvaro Fernandez, Yves Krüger, Jane Adigun, Stéphane Affolter, and Markus Leuenberger
Clim. Past, 19, 1847–1862, https://doi.org/10.5194/cp-19-1847-2023, 2023
The southern coast of South Africa hosts some key archeological sites for the study of early human evolution. Here we present a short but high-resolution record of past changes in the hydroclimate and temperature on the southern coast of South Africa based on the study of a speleothem collected from Bloukrantz Cave. Overall, the paleoclimate indicators suggest stable temperature from 48.3 to 45.2 ka, whereas precipitation was variable, with marked short drier episodes.
PubDate: Mon, 25 Sep 2023 16:45:23 +020
DOI: 10.5194/cp-19-1847-2023 2023
- Upper-ocean temperature characteristics in the subantarctic southeastern
Pacific based on biomarker reconstructions
Abstract: Upper-ocean temperature characteristics in the subantarctic southeastern Pacific based on biomarker reconstructions
Julia Rieke Hagemann, Lester Lembke-Jene, Frank Lamy, Maria-Elena Vorrath, Jérôme Kaiser, Juliane Müller, Helge W. Arz, Jens Hefter, Andrea Jaeschke, Nicoletta Ruggieri, and Ralf Tiedemann
Clim. Past, 19, 1825–1845, https://doi.org/10.5194/cp-19-1825-2023, 2023
Alkenones and glycerol dialkyl glycerol tetraether lipids (GDGTs) are common biomarkers for past water temperatures. In high latitudes, determining temperature reliably is challenging. We analyzed 33 Southern Ocean sediment surface samples and evaluated widely used global calibrations for both biomarkers. For GDGT-based temperatures, previously used calibrations best reflect temperatures>5° C; (sub)polar temperature bias necessitates a new calibration which better aligns with modern values.
PubDate: Thu, 21 Sep 2023 16:45:23 +020
DOI: 10.5194/cp-19-1825-2023 2023
- Antarctic Tipping points triggered by the mid-Pliocene warm climate
Abstract: Antarctic Tipping points triggered by the mid-Pliocene warm climate
Javier Blasco, Ilaria Tabone, Daniel Moreno-Parada, Alexander Robinson, Jorge Alvarez-Solas, Frank Pattyn, and Marisa Montoya
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-76,2023
Preprint under review for CP (discussion: open, 0 comments)
In this study, we assess Antarctic tipping points which may had been crossed during the mid-pliocene warm period. For this we use data from the PlioMIP2 ensemble. Additionally, we investigate various sources of uncertainty, like ice dynamics and bedrock configuration. Our research significantly enhances our comprehension of Antarctica's response to a warming climate, shedding light on potential future tipping points that may be surpassed.
PubDate: Wed, 20 Sep 2023 19:27:43 +020
DOI: 10.5194/cp-2023-762023
- Multi-annual variability of a new proxy-constrained modeled AMOC from
1450–1780 CE
Abstract: Multi-annual variability of a new proxy-constrained modeled AMOC from 1450–1780 CE
Eric Samakinwa, Christoph C. Raible, Ralf Hand, Andrew R. Friedman, and Stefan Brönnimann
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-67,2023
Preprint under review for CP (discussion: open, 0 comments)
In this study, we nudged a stand-alone ocean model MPI-OM to proxy-reconstructed SST. Based on these model simulations, we introduce new estimates of the AMOC variations during the period 1450–1780 through a 10-member ensemble simulation with a novel nudging technique. Our approach reaffirms the known mechanisms of AMOC variability and also improves existing knowledge of the interplay between the AMOC and the NAO during the AMOC's weak and strong phases.
PubDate: Mon, 18 Sep 2023 19:27:43 +020
DOI: 10.5194/cp-2023-672023
- Polar amplification of orbital-scale climate variability in the early
Eocene greenhouse world
Abstract: Polar amplification of orbital-scale climate variability in the early Eocene greenhouse world
Chris D. Fokkema, Tobias Agterhuis, Danielle Gerritsma, Myrthe de Goeij, Xiaoqing Liu, Pauline de Regt, Addison Rice, Laurens Vennema, Claudia Agnini, Peter K. Bijl, Joost Frieling, Matthew Huber, Francien Peterse, and Appy Sluijs
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-70,2023
Preprint under review for CP (discussion: open, 0 comments)
Polar amplification (PA) is a key uncertainty in climate projections. The factors that dominantly control PA are difficult to separate. Here we provide an estimate for the non-ice-related PA by reconstructing tropical ocean temperature variability from the ice-free early Eocene, which we compare to deep-ocean-derived high latitude temperature variability across short-lived warming periods. We find a PA factor of 1.7–2.3 on 20-kyr timescales, which matches previous multi-million-year estimates.
PubDate: Mon, 18 Sep 2023 19:27:43 +020
DOI: 10.5194/cp-2023-702023
- Atmosphere–cryosphere interactions during the last phase of the Last
Glacial Maximum (21 ka) in the European Alps
Abstract: Atmosphere–cryosphere interactions during the last phase of the Last Glacial Maximum (21 ka) in the European Alps
Costanza Del Gobbo, Renato R. Colucci, Giovanni Monegato, Manja Žebre, and Filippo Giorgi
Clim. Past, 19, 1805–1823, https://doi.org/10.5194/cp-19-1805-2023, 2023
We studied atmosphere–cryosphere interaction during the last phase of the Last Glacial Maximum in the Alpine region, using a high-resolution regional climate model. We analysed the climate south and north of the Alps, using a detailed map of the Alpine equilibrium line altitude (ELA) to study the mechanism that sustained the Alpine glaciers at 21 ka. The Genoa low and a mild Mediterranean Sea led to frequent snowfall in the southern Alps, thus preserving the glaciers and lowering the ELA.
PubDate: Fri, 15 Sep 2023 00:07:26 +020
DOI: 10.5194/cp-19-1805-2023 2023
- Tracing seasonal signals in dry/wet status for regions with simultaneous
rain and heat from Eastern and Central Asia since the Last Glacial Maximum
Abstract: Tracing seasonal signals in dry/wet status for regions with simultaneous rain and heat from Eastern and Central Asia since the Last Glacial Maximum
Simin Peng, Yu Li, Zhansen Zhang, Mingjun Gao, Xiaowen Chen, Junjie Duan, and Yaxin Xue
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-71,2023
Preprint under review for CP (discussion: open, 0 comments)
The synchronization of rain and heat is an important hypothesis, which contains the summer precipitation regime and the winter precipitation regime. In this paper, EA and part of CA with the summer precipitation regime are selected to study dry/wet status in multi-time scales since the LGM. This study found that although climate difference in EA and CA universally exists, climate linkages in EA and part of CA with the summer precipitation regime can be uncovered.
PubDate: Fri, 15 Sep 2023 00:07:26 +020
DOI: 10.5194/cp-2023-712023
- 600 years of wine must quality and April to August temperatures in Western
Europe 1420–2019
Abstract: 600 years of wine must quality and April to August temperatures in Western Europe 1420–2019
Christian Pfister, Stefan Brönnimann, Andres Altwegg, Rudolf Brázdil, Laurent Litzenburger, Daniele Lorusso, and Thomas Pliemon
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-66,2023
Preprint under review for CP (discussion: open, 1 comment)
This study examines the sugar content of wine must as an indicator of warm season temperatures since 1420. Winegrowers in Western Europe recorded it early on, as it mattered for the wine price. Their estimates agree well with measured sugar content, warm season temperatures and the frequency of large-scale weather events. Wine quality data go further back than grape harvest dates and complement them, notably in hot summers. After the warming since 1990, only good qualities were obtained.
PubDate: Fri, 15 Sep 2023 00:07:26 +020
DOI: 10.5194/cp-2023-662023
- Do phenomenological dynamical paleoclimate models have physical similarity
with Nature' Seemingly, not all of them do
Abstract: Do phenomenological dynamical paleoclimate models have physical similarity with Nature' Seemingly, not all of them do
Mikhail Y. Verbitsky and Michel Crucifix
Clim. Past, 19, 1793–1803, https://doi.org/10.5194/cp-19-1793-2023, 2023
Are phenomenological dynamical paleoclimate models physically similar to Nature' We demonstrated that though they may be very accurate in reproducing empirical time series, this is not sufficient to claim physical similarity with Nature until similarity parameters are considered. We suggest that the diagnostics of physical similarity should become a standard procedure before a phenomenological model can be utilized for interpretations of historical records or future predictions.
PubDate: Wed, 13 Sep 2023 00:01:42 +020
DOI: 10.5194/cp-19-1793-2023 2023
- Duration and ice thickness of a Late Holocene outlet glacier advance near
Narsarsuaq, southern Greenland
Abstract: Duration and ice thickness of a Late Holocene outlet glacier advance near Narsarsuaq, southern Greenland
Peter J. K. Puleo and Yarrow Axford
Clim. Past, 19, 1777–1791, https://doi.org/10.5194/cp-19-1777-2023, 2023
We used two lake sediment records at different elevations and landscape evidence to find that a southern Greenland outlet glacier advanced ~ 3700 years ago and then retreated ~ 1600 years ago. This retreat is unlike other nearby outlet glaciers, possibly because of the complex local ice structure or greater sensitivity to snowfall. We also find that the advanced ice surface had an elevation of ~ 670 m a.s.l. (~ 250 m higher than today) from ~ 3700 to 1600 years ago.
PubDate: Fri, 08 Sep 2023 18:32:39 +020
DOI: 10.5194/cp-19-1777-2023 2023
- Carbon isotope chemostratigraphy, geochemistry, and biostratigraphy of the
Paleocene–Eocene Thermal Maximum, deepwater Wilcox Group, Gulf of Mexico
(USA)
Abstract: Carbon isotope chemostratigraphy, geochemistry, and biostratigraphy of the Paleocene–Eocene Thermal Maximum, deepwater Wilcox Group, Gulf of Mexico (USA)
Glenn R. Sharman, Eugene Szymanski, Rebecca A. Hackworth, Alicia C. M. Kahn, Lawrence A. Febo, Jordan Oefinger, and Gunnar M. Gregory
Clim. Past, 19, 1743–1775, https://doi.org/10.5194/cp-19-1743-2023, 2023
This study examines deepwater deposits within the Gulf of Mexico (USA) that record an episode of pronounced global warming that occurred ∼56 million years ago. We show that the supply of sand and silt into the basin shut off after a delay of about 30 000 years, followed by an influx of clay derived from deep erosion of central North America. Our results are consistent with other studies that indicate rapid sea-level rise, ocean acidification, and decreased oxygen during this warming event
PubDate: Tue, 05 Sep 2023 19:49:44 +020
DOI: 10.5194/cp-19-1743-2023 2023
- Sea-level and monsoonal control on the Maldives carbonate platform (Indian
Ocean) over the last 1.3 million years
Abstract: Sea-level and monsoonal control on the Maldives carbonate platform (Indian Ocean) over the last 1.3 million years
Montserrat Alonso-Garcia, Jesus Reolid, Francisco J. Jimenez-Espejo, Or M. Bialik, Carlos A. Alvarez Zarikian, Juan C. Laya, Igor Carrasquiera, Luigi Jovane, John J. G. Reijmer, Christian Betzler, and Gregor P. Eberli
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-68,2023
Preprint under review for CP (discussion: open, 0 comments)
This article presents a record of carbonate production in the Maldives atolls (Indian Ocean) by coral reefs and other calcareous organisms. During the last 1.3 Million years the carbonate production was controlled by sea-level variations but also by the oceanographic and atmospheric conditions linked to the Indian monsoon. A clear shift towards a more successful carbonate production is observed at about 900.000 years and about 430.000 years, probably setting up the modern reef environments.
PubDate: Tue, 05 Sep 2023 19:49:44 +020
DOI: 10.5194/cp-2023-682023
- Weathering trends in the Norian through geochemical and rock magnetic
analyses from the Pignola-Abriola Section (Lagonegro Basin, Italy)
Abstract: Weathering trends in the Norian through geochemical and rock magnetic analyses from the Pignola-Abriola Section (Lagonegro Basin, Italy)
Matteo Maron, Tetsuji Onoue, Sara Satolli, Katsuhito Soda, Honami Sato, Giovanni Muttoni, and Manuel Rigo
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-61,2023
Preprint under review for CP (discussion: open, 0 comments)
For a better knowledge of the climate perturbation occurred in the lattermost part of the Triassic Period (Norian-Rhaetian), we investigated the geochemical and rock magnetic properties of the limestones of the Pignola-Abriola section (Lagonegro Basin, Italy). Our investigation revealed at least a major episode of enhanced weathering occurring in the late Norian (~217–211 Ma), possibly related to the Cimmerian orogen and/or the northward motion of Pangea across the equatorial humid belt.
PubDate: Thu, 31 Aug 2023 22:25:48 +020
DOI: 10.5194/cp-2023-612023
- Late Aptian paleoclimate reconstruction of the Brazilian equatorial
margin: inferences from palynology
Abstract: Late Aptian paleoclimate reconstruction of the Brazilian equatorial margin: inferences from palynology
Michelle Cardoso da Silva Giannerini, Marcelo de Araujo Carvalho, Cecília Cunha Lana, Gustavo Santiago, Natália de Paula Sá, and Gabriel da Cunha Correia
Clim. Past, 19, 1715–1742, https://doi.org/10.5194/cp-19-1715-2023, 2023
This study analyzed ancient climate patterns using plant fossils called palynomorphs. We identified 69 different palynomorphs from different plant groups (e.g., ferns, gymnosperms, angiosperms) and used statistical methods to support our findings. We found a trend towards increased humidity, likely influenced by a weather phenomenon called the Intertropical Convergence Zone.
PubDate: Fri, 25 Aug 2023 14:39:05 +020
DOI: 10.5194/cp-19-1715-2023 2023
- A Comparison of South Pacific Antarctic Sea Ice and Atmospheric
Circulation Reconstructions Since 1900
Abstract: A Comparison of South Pacific Antarctic Sea Ice and Atmospheric Circulation Reconstructions Since 1900
Ryan Fogt, Quentin Dalaiden, and Gemma O'Connor
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-63,2023
Preprint under review for CP (discussion: open, 0 comments)
Antarctic sea ice is rapidly changing, with record lows set in 2017, 2022, and 2023 following decades of increase. To place these changes in a longer historical context, reconstructions have been created, however they are quite different prior to observations. Here we find that the differences are more strongly tied to the implied connection of each reconstruction with the atmospheric circulation, rather than differences in seasonality or geographic representation.
PubDate: Thu, 24 Aug 2023 18:06:48 +020
DOI: 10.5194/cp-2023-632023
- An age scale for new climate records from Sherman Island, West Antarctica
Abstract: An age scale for new climate records from Sherman Island, West Antarctica
Isobel Rowell, Carlos Martin, Robert Mulvaney, Helena Pryer, Dieter Tetzner, Emily Doyle, Hara Madhav Talasila, Jilu Li, and Eric Wolff
Clim. Past, 19, 1699–1714, https://doi.org/10.5194/cp-19-1699-2023, 2023
We present an age scale for a new type of ice core from a vulnerable region in West Antarctic, which is lacking in longer-term (greater than a few centuries) ice core records. The Sherman Island core extends to greater than 1 kyr. We provide modelling evidence for the potential of a 10 kyr long core. We show that this new type of ice core can be robustly dated and that climate records from this core will be a significant addition to existing regional climate records.
PubDate: Thu, 17 Aug 2023 18:14:13 +020
DOI: 10.5194/cp-19-1699-2023 2023
- Assessing environmental change associated with early Eocene hyperthermals
in the Atlantic Coastal Plain, USA
Abstract: Assessing environmental change associated with early Eocene hyperthermals in the Atlantic Coastal Plain, USA
William Rush, Jean Self-Trail, Yang Zhang, Appy Sluijs, Henk Brinkhuis, James Zachos, James G. Ogg, and Marci Robinson
Clim. Past, 19, 1677–1698, https://doi.org/10.5194/cp-19-1677-2023, 2023
The Eocene contains several brief warming periods referred to as hyperthermals. Studying these events and how they varied between locations can help provide insight into our future warmer world. This study provides a characterization of two of these events in the mid-Atlantic region of the USA. The records of climate that we measured demonstrate significant changes during this time period, but the type and timing of these changes highlight the complexity of climatic changes.
PubDate: Thu, 17 Aug 2023 18:14:13 +020
DOI: 10.5194/cp-19-1677-2023 2023
- Technical Note: A best-practice approach to calculating the Southern
Annular Mode index
Abstract: Technical Note: A best-practice approach to calculating the Southern Annular Mode index
Laura Velasquez-Jimenez and Nerilie J. Abram
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-64,2023
Preprint under review for CP (discussion: open, 0 comments)
The Southern Annular Mode (SAM) influences climate in the Southern hemisphere. We investigate the effects of calculation method and data used to calculate the SAM index, and how it influences the relationship between the SAM and climate. We propose a method to calculate a dimensional SAM index that facilitate consistency between studies, including when using different data resolutions, avoiding distortion of SAM impacts and allow more reliable results of past and future SAM trends.
PubDate: Thu, 17 Aug 2023 18:14:13 +020
DOI: 10.5194/cp-2023-642023
- Continuous synchronization of the Greenland ice-core and U-Th timescales
using probabilistic inversion
Abstract: Continuous synchronization of the Greenland ice-core and U-Th timescales using probabilistic inversion
Francesco Muschitiello and Marco Antonio Aquino-Lopez
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-65,2023
Preprint under review for CP (discussion: open, 0 comments)
The first continuously measured transfer function that quantifies the age difference between the Greenland Ice-Core Chronology 2005 (GICC05) and the U-Th timescale is presented. The transfer function was generated using a novel probabilistic algorithm for the synchronization of proxy signals. The results greatly improve the accuracy and precision of previous synchronization estimates and reveal that the annual-layer counting error of GICC05 is less systematic than previously assumed.
PubDate: Wed, 16 Aug 2023 18:14:13 +020
DOI: 10.5194/cp-2023-652023
- Surface mass balance and climate of the Last Glacial Maximum northern
hemisphere ice sheets: simulations with CESM2.1
Abstract: Surface mass balance and climate of the Last Glacial Maximum northern hemisphere ice sheets: simulations with CESM2.1
Sarah Louise Bradley, Raymond Sellevold, Michele Petrini, Miren Vizcaino, Sotiria Georgiou, Jiang Zhu, Bette L. Otto-Bliesner, and Marcus Lofverstrom
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-62,2023
Preprint under review for CP (discussion: open, 0 comments)
The Last Glacial Maximum was the most recent period with large ice sheets in the Europe and North America. We provide a detailed analysis of surface mass and energy components for two time periods the bracket the LGM: 26 ka and 21 ka. We use an earth system model which has been adopted for modern ice sheets. We find that all northern hemisphere ice sheets have a positive surface mass balance apart from the British and Irish ice sheet and the North American ice sheet complex.
PubDate: Tue, 15 Aug 2023 15:44:04 +020
DOI: 10.5194/cp-2023-622023
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