Last interglacial hydroclimate in the Italian Prealps reconstructed from speleothem multi-proxy records (Bigonda Cave, NE Italy)

2021 ◽  
Vol 272 ◽  
pp. 107243
Author(s):  
Vanessa E. Johnston ◽  
Andrea Borsato ◽  
Silvia Frisia ◽  
Christoph Spötl ◽  
John C. Hellstrom ◽  
...  
Keyword(s):  
Last Interglacial ◽  
Proxy Records ◽  
Ne Italy

scholarly journals Detection and Characterisation of Eemian Marine Tephra Layers within the Sapropel S5 Sediments of the Aegean and Levantine Seas

Quaternary ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 6
Author(s):  
Christopher Satow ◽  
Katharine M. Grant ◽  
Sabine Wulf ◽  
Hartmut Schulz ◽  
Addison Mallon ◽  
...  
Keyword(s):  
Major Element ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Proxy Records ◽  
Last Interglacial Period ◽  
Levantine Basin ◽  
History Of ◽  
Tephra Layers

The Eemian was the last interglacial period (~130 to 115 ka BP) to precede the current interglacial. In Eastern Mediterranean marine sediments, it is marked by a well-developed and organic-rich “sapropel” layer (S5), which is thought to reflect an intensification and northward migration of the African monsoon rain belt over orbital timescales. However, despite the importance of these sediments, very little proxy-independent stratigraphic information is available to enable rigorous correlation of these sediments across the region. This paper presents the first detailed study of visible and non-visible (cryptotephra) layers found within these sediments at three marine coring sites: ODP Site 967B (Levantine Basin), KL51 (South East of Crete) and LC21 (Southern Aegean Sea). Major element analyses of the glass component were used to distinguish four distinct tephra events of Santorini (e.g., Vourvoulos eruption) and possible Anatolian provenance occurring during the formation of S5. Interpolation of core chronologies provides provisional eruption ages for the uppermost tephra (unknown Santorini, 121.8 ± 2.9 ka) and lowermost tephra (Anatolia or Kos/Yali/Nisyros, 126.4 ± 2.9 ka). These newly characterised tephra deposits have also been set into the regional tephrostratigraphy to illustrate the potential to precisely synchronise marine proxy records with their terrestrial counterparts, and also contribute to the establishment of a more detailed volcanic history of the Eastern Mediterranean.

scholarly journals High-resolution mineral dust and sea ice proxy records from the Talos Dome ice core

2013 ◽  
Vol 9 (6) ◽  
pp. 2789-2807 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
P. R. Kaufmann ◽  
S. Albani ◽  
C. Barbante ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Transport Model ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Last Interglacial ◽  
The Holocene ◽  
Proxy Records

Abstract. In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the Southern Ocean. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.

scholarly journals Greenland Ice Sheet influence on Last Interglacial climate: global sensitivity studies performed with an atmosphere–ocean general circulation model

2016 ◽  
Vol 12 (6) ◽  
pp. 1313-1338 ◽  
Author(s):  
Madlene Pfeiffer ◽  
Gerrit Lohmann
Keyword(s):  
Temperature Change ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Minor Importance ◽  
Last Interglacial ◽  
Proxy Data ◽  
Proxy Records ◽  
Thermal Maximum ◽  
Sensitivity Studies ◽  
The Impact

Abstract. During the Last Interglacial (LIG, ∼130–115 kiloyears (kyr) before present (BP)), the northern high latitudes were characterized by higher temperatures than those of the late Holocene and a lower Greenland Ice Sheet (GIS). However, the impact of a reduced GIS on the global climate has not yet been well constrained. In this study, we quantify the contribution of the GIS to LIG warmth by performing various sensitivity studies based on equilibrium simulations, employing the Community Earth System Models (COSMOS), with a focus on height and extent of the GIS. We present the first study on the effects of a reduction in the GIS on the surface temperature (TS) on a global scale and separate the contribution of astronomical forcing and changes in GIS to LIG warmth. The strong Northern Hemisphere summer warming of approximately 2 °C (with respect to pre-industrial) is mainly caused by increased summer insolation. Reducing the height by  ∼ 1300 m and the extent of the GIS does not have a strong influence during summer, leading to an additional global warming of only +0.24 °C compared to the purely insolation-driven LIG. The effect of a reduction in the GIS is, however, strongest during local winter, with up to +5 °C regional warming and with an increase in global average temperature of +0.48 °C. In order to evaluate the performance of our LIG simulations, we additionally compare the simulated TS anomalies with marine and terrestrial proxy-based LIG temperature anomalies derived from three different proxy data compilations. Our model results are in good agreement with proxy records with respect to the warming pattern but underestimate the magnitude of temperature change when compared to reconstructions, suggesting a potential misinterpretation of the proxy records or deficits in our model. However, we are able to partly reduce the mismatch between model and data by additionally taking into account the potential seasonal bias of the proxy record and/or the uncertainties in the dating of the proxy records for the LIG thermal maximum. The seasonal bias and the uncertainty of the timing are estimated from new transient model simulations covering the whole LIG. The model–data comparison improves for proxies that represent annual mean temperatures when the GIS is reduced and when we take the local thermal maximum during the LIG (130–120 kyr BP) into account. For proxy data that represent summer temperatures, changes in the GIS are of minor importance for sea surface temperatures. However, the annual mean and summer temperature change over Greenland in the reduced GIS simulations seems to be overestimated as compared to the local ice core data, which could be related to the interpretation of the recorder system and/or the assumptions of GIS reduction. Thus, the question regarding the real size of the GIS during the LIG has yet to be answered.

scholarly journals Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading

2016 ◽  
Vol 12 (8) ◽  
pp. 1693-1719 ◽  
Author(s):  
Timothé Bolliet ◽  
Patrick Brockmann ◽  
Valérie Masson-Delmotte ◽  
Franck Bassinot ◽  
Valérie Daux ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Climate Models ◽  
Transfer Functions ◽  
Ice Cores ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Global Database ◽  
Proxy Records ◽  
Online Portal ◽  
Data Browsing

Abstract. Past climate is an important benchmark to assess the ability of climate models to simulate key processes and feedbacks. Numerous proxy records exist for stable isotopes of water and/or carbon, which are also implemented inside the components of a growing number of Earth system model. Model–data comparisons can help to constrain the uncertainties associated with transfer functions. This motivates the need of producing a comprehensive compilation of different proxy sources. We have put together a global database of proxy records of oxygen (δ18O), hydrogen (δD) and carbon (δ13C) stable isotopes from different archives: ocean and lake sediments, corals, ice cores, speleothems and tree-ring cellulose. Source records were obtained from the georeferenced open access PANGAEA and NOAA libraries, complemented by additional data obtained from a literature survey. About 3000 source records were screened for chronological information and temporal resolution of proxy records. Altogether, this database consists of hundreds of dated δ18O, δ13C and δD records in a standardized simple text format, complemented with a metadata Excel catalog. A quality control flag was implemented to describe age markers and inform on chronological uncertainty. This compilation effort highlights the need to homogenize and structure the format of datasets and chronological information as well as enhance the distribution of published datasets that are currently highly fragmented and scattered. We also provide an online portal based on the records included in this database with an intuitive and interactive platform (http://climateproxiesfinder.ipsl.fr/), allowing one to easily select, visualize and download subsets of the homogeneously formatted records that constitute this database, following a choice of search criteria, and to upload new datasets. In the last part, we illustrate the type of application allowed by our database by comparing several key periods highly investigated by the paleoclimate community. For coherency with the Paleoclimate Modelling Intercomparison Project (PMIP), we focus on records spanning the past 200 years, the mid-Holocene (MH, 5.5–6.5 ka; calendar kiloyears before 1950), the Last Glacial Maximum (LGM, 19–23 ka), and those spanning the last interglacial period (LIG, 115–130 ka). Basic statistics have been applied to characterize anomalies between these different periods. Most changes from the MH to present day and from LIG to MH appear statistically insignificant. Significant global differences are reported from LGM to MH with regional discrepancies in signals from different archives and complex patterns.

scholarly journals Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

2016 ◽  
Vol 12 (10) ◽  
pp. 2011-2031 ◽  
Author(s):  
Niklaus Merz ◽  
Andreas Born ◽  
Christoph C. Raible ◽  
Thomas F. Stocker
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Labrador Sea ◽  
Last Interglacial ◽  
Atlantic Sector ◽  
Nordic Seas ◽  
Proxy Records ◽  
Ice Retreat ◽  
Sea Ice Retreat

Abstract. The last interglacial, also known as the Eemian, is characterized by warmer than present conditions at high latitudes. This is implied by various Eemian proxy records as well as by climate model simulations, though the models mostly underestimate the warming with respect to proxies. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics further show large variations between different climate models, and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea ice and sea surface temperatures changes for the Eemian climate, in particular in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and thus a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale spread of the warming resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous heat advection rather than by radiation or condensation processes. In addition, the sea ice perturbations lead to changes in the hydrological cycle. Our results consequently imply that both temperature and snow accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 °C above present day based on the NEEM δ15N record can be reconstructed by the CCSM4 model for the scenario of a substantial sea ice retreat in the Nordic Seas combined with a reduced Greenland ice sheet.

scholarly journals A multi-model assessment of last interglacial temperatures

2013 ◽  
Vol 9 (2) ◽  
pp. 699-717 ◽  
Author(s):  
D. J. Lunt ◽  
A. Abe-Ouchi ◽  
P. Bakker ◽  
A. Berger ◽  
P. Braconnot ◽  
...  
Keyword(s):  
Climate Model ◽  
Numerical Models ◽  
Quantitative Agreement ◽  
Model Assessment ◽  
Last Interglacial ◽  
Model Simulations ◽  
Proxy Records ◽  
Robust Model ◽  
Uncertainty Estimates ◽  
Climate Model Simulations

Abstract. The last interglaciation (~130 to 116 ka) is a time period with a strong astronomically induced seasonal forcing of insolation compared to the present. Proxy records indicate a significantly different climate to that of the modern, in particular Arctic summer warming and higher eustatic sea level. Because the forcings are relatively well constrained, it provides an opportunity to test numerical models which are used for future climate prediction. In this paper we compile a set of climate model simulations of the early last interglaciation (130 to 125 ka), encompassing a range of model complexities. We compare the simulations to each other and to a recently published compilation of last interglacial temperature estimates. We show that the annual mean response of the models is rather small, with no clear signal in many regions. However, the seasonal response is more robust, and there is significant agreement amongst models as to the regions of warming vs cooling. However, the quantitative agreement of the model simulations with data is poor, with the models in general underestimating the magnitude of response seen in the proxies. Taking possible seasonal biases in the proxies into account improves the agreement, but only marginally. However, a lack of uncertainty estimates in the data does not allow us to draw firm conclusions. Instead, this paper points to several ways in which both modelling and data could be improved, to allow a more robust model–data comparison.

scholarly journals Tropical Atlantic Cooling and Freshening in the Middle of the Last Interglacial From Coral Proxy Records

2019 ◽  
Vol 46 (14) ◽  
pp. 8289-8299 ◽  
Author(s):  
William M. Brocas ◽  
Thomas Felis ◽  
Manfred Mudelsee
Keyword(s):  
Tropical Atlantic ◽  
Last Interglacial ◽  
Proxy Records

scholarly journals A multi-model assessment of last interglacial temperatures

2012 ◽  
Vol 8 (4) ◽  
pp. 3657-3691 ◽  
Author(s):  
D. J. Lunt ◽  
A. Abe-Ouchi ◽  
P. Bakker ◽  
A. Berger ◽  
P. Braconnot ◽  
...  
Keyword(s):  
Climate Model ◽  
Numerical Models ◽  
Quantitative Agreement ◽  
Model Complexity ◽  
Model Assessment ◽  
Last Interglacial ◽  
Proxy Records ◽  
Robust Model ◽  
Uncertainty Estimates ◽  
Climate Model Simulations

Abstract. The Last Interglaciation (∼130 to 116 ka) is a time period with a strong astronomically-induced seasonal forcing of insolation compared to modern. Proxy records indicate a significantly different climate to that of the modern, in particular Arctic summer warming and higher eustatic sea level. Because the forcings are relatively well constrained, it provides an opportunity to test numerical models which are used for future climate prediction. In this paper, we compile a set of climate model simulations of the early Last Interglaciation (130 to 125 ka), encompassing a range of model complexity. We compare the models to each other, and to a recently published compilation of Last Interglacial temperature estimates. We show that the annual mean response of the models is rather small, with no clear signal in many regions. However, the seasonal response is more robust, and there is significant agreement amongst models as to the regions of warming vs. cooling. However, the quantitative agreement of the models with data is poor, with the models in general underestimating the magnitude of response seen in the proxies. Taking possible seasonal biases in the proxies into account improves the agreement marginally, but the agreement is still far from perfect. However, a lack of uncertainty estimates in the data does not allow us to draw firm conclusions. Instead, this paper points to several ways in which both modelling and data could be improved, to allow a more robust model-data comparison.

scholarly journals Greenland Ice Sheet influence on Last Interglacial climate: global sensitivity studies performed with an atmosphere–ocean general circulation model

2015 ◽  
Vol 11 (2) ◽  
pp. 933-995 ◽  
Author(s):  
M. Pfeiffer ◽  
G. Lohmann
Keyword(s):  
General Circulation ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
High Latitudes ◽  
Last Interglacial ◽  
Proxy Records ◽  
Sensitivity Studies ◽  
The Impact

Abstract. During the Last Interglacial (LIG, 130–115 kiloyear before present), the northern high latitudes experienced higher temperatures than those of the late Holocene with a notably lower Greenland Ice Sheet (GIS). However, the impact of a reduced GIS on the global climate has not yet been well constrained. In this study, we quantify the contribution of the GIS to LIG warmth by performing various sensitivity studies, employing the Community Earth System Models (COSMOS), with a focus on height and extent of the GIS. In order to asses the effects of insolation changes over time and for a comparison of LIG climate with the current interglacial, we perform transient simulations covering the whole LIG and Holocene. We analyze surface air temperature (SAT) and separate the contribution of different forcings to LIG warmth. The strong Northern Hemisphere warming is mainly caused by increased summer insolation. Reducing the height and extent of the GIS leads to a warming of several degrees Celcius in the northern and southern high latitudes during local winter. In order to evaluate the performance of our LIG simulations, we additionally compare the simulated SAT anomalies with marine and terrestrial proxy-based LIG temperature anomalies. Our model results are in good agreement with proxy records with respect to the pattern, but underestimate the reconstructed temperatures. We are able to reduce the mismatch between model and data by taking into account the potential seasonal bias of the proxy record and the uncertainties in the dating of the proxy records for the LIG thermal maximum. The seasonal bias and the uncertainty of the timing are estimated from our own transient model simulations. We note however that our LIG simulations are not able to reproduce the full magnitude of temperature changes indicated by the proxies, suggesting a potential misinterpretation of the proxy records or deficits of our model.

scholarly journals An interactive tool for navigation within a database of water and carbon stable isotope records from natural archives

2016 ◽  
Author(s):  
T. Bolliet ◽  
P. Brockmann ◽  
V. Masson-Delmotte ◽  
F. Bassinot ◽  
V. Daux ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Climate Models ◽  
Transfer Functions ◽  
Ice Cores ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Global Database ◽  
Proxy Records ◽  
Online Portal ◽  
Stable Isotopes Of Water

Abstract. Past climate is an important benchmark to assess the ability of climate models to simulate key processes and feedbacks. Numerous proxy records exist for stable isotopes of water and/or carbon, which are also implemented inside the components of a growing number of Earth system model. Model-data comparisons can help to constrain the uncertainties associated with transfer functions. This motivates the need of producing a comprehensive compilation of different proxy sources. We have put together a global database of proxy records of oxygen (δ18O), hydrogen (δD) and carbon (δ13C) stable isotopes from different archives: ocean and lake sediments, corals, ice cores, speleothems and tree-ring cellulose. Source records were obtained from the georeferenced open access PANGAEA and NOAA libraries, complemented by additional data obtained from a literature survey. About 3000 source records were screened for chronological information and temporal resolution of proxy records. Altogether, this database consists of hundreds of dated δ18O, δ13C and δD records in a standardized simple text format, complemented with a metadata Excel catalog. For coherency with the Paleoclimate Modelling Intercomparison Project (PMIP), we focus on records spanning the past 200 years, the mid-Holocene (MH, 5.5-6.5 ka; calendar kilo years before 1950), and the Last Glacial Maximum (LGM, 19-23 ka), and those spanning the last interglacial period (LIG, 115-130 ka). For the LGM, a quality control flag was implemented to describe age markers and inform on chronological uncertainty. Basic statistics have been applied to characterize anomalies between these different periods. Most changes from the MH to present day, and LIG to MH appear statistically insignificant. Significant global differences are reported from LGM to MH with regional discrepancies in signals from different archives and complex patterns. This compilation effort highlights the need to homogenize the format of datasets and chronological information, and enhance the distribution of published datasets that are currently highly-fragmented and scattered. We also provide an online portal with an intuitive and interactive platform (http://climateproxiesfinder.ipsl.fr/), allowing one to easily select, visualize and download subsets of the homogeneously-formatted records that conform this database, following a choice of search criteria, and to upload new datasets.

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