scholarly journals A refined TALDICE-1a age scale from 55 to 112 ka before present for the Talos Dome ice core based on high-resolution methane measurements

2011 ◽  
Vol 7 (3) ◽  
pp. 1001-1009 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
M. Bigler ◽  
H. Fischer ◽  
T. F. Stocker
Keyword(s):  
High Resolution ◽  
Ross Sea ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Ice Age ◽  
Before Present ◽  
Bottom Part ◽  
Analysis Technique ◽  
The Impact

Abstract. A precise synchronization of different climate records is indispensable for a correct dynamical interpretation of paleoclimatic data. A chronology for the TALDICE ice core from the Ross Sea sector of East Antarctica has recently been presented based on methane synchronization with Greenland and the EDC ice cores and δ18Oice synchronization with EDC in the bottom part (TALDICE-1). Using new high-resolution methane data obtained with a continuous flow analysis technique, we present a refined age scale for the age interval from 55–112 thousand years (ka) before present, where TALDICE is synchronized with EDC. New and more precise tie points reduce the uncertainties of the age scale from up to 1900 yr in TALDICE-1 to below 1100 yr over most of the refined interval and shift the Talos Dome dating to significantly younger ages during the onset of Marine Isotope Stage 3. Thus, discussions of climate dynamics at sub-millennial time scales are now possible back to 110 ka, in particular during the inception of the last ice age. Calcium data of EDC and TALDICE are compared to show the impact of the refinement to the synchronization of the two ice cores not only for the gas but also for the ice age scale.

scholarly journals A refined TALDICE-1a age scale from 55 to 112 ka before present for the Talos Dome ice core based on high-resolution methane measurements

2011 ◽  
Vol 7 (2) ◽  
pp. 1175-1193 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
M. Bigler ◽  
H. Fischer ◽  
T. F. Stocker
Keyword(s):  
High Resolution ◽  
Ross Sea ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Ice Age ◽  
Before Present ◽  
Bottom Part ◽  
Analysis Technique ◽  
The Impact

Abstract. A precise synchronization of different climate records is indispensable for a correct dynamical interpretation of paleoclimatic data. A chronology for the TALDICE ice core from the Ross Sea sector of East Antarctica has recently been presented based on methane synchronization with Greenland and the EDC ice cores and δ18Oice synchronization with EDC in the bottom part (TALDICE-1). By the use of new high-resolution methane data, obtained with a continuous flow analysis technique, we present a refined age scale for the age interval from 55–112 ka before present where TALDICE is synchronized with EDC. New and more precise tie points reduce the uncertainties of the age scale from up to 2000 yr in TALDICE-1 to below 1000 yr over most of the refined interval. Thus, discussions of climate dynamics at sub-millennial time scales are now possible back to 110 ka, in particular during the inception of the last ice age. Calcium data of EDC and TALDICE are compared to show the impact of the refinement to the synchronization of the two ice cores not only for the gas but also for the ice age scale.

Tephra in the Greenland Ice cores: Insights into Icelandic volcano-climate impacts

2021 ◽  
Author(s):  
Imogen Gabriel ◽  
Gill Plunkett ◽  
Peter Abbott ◽  
Bergrún Óladóttir ◽  
Joseph McConnell ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Climate Impacts ◽  
Geochemical Analysis ◽  
Volcanic Events ◽  
Societal Impacts ◽  
The Impact ◽  
Ice Core Records

<p>Volcanic eruptions are considered as one of the primary natural drivers for changes in the global climate system and understanding the impact of past eruptions on the climate is integral to adopt appropriate responses towards future volcanic eruptions.</p><p>The Greenland ice core records are dominated by Icelandic eruptions, with several volcanic systems (Katla, Hekla, Bárðarbunga-Veiðivötn and Grimsvötn) being highly active throughout the Holocene. A notable period of increased Icelandic volcanic activity occurred between 500-1250 AD and coincided with climatic changes in the North Atlantic region which may have facilitated the Viking settlement of Greenland and Iceland. However, a number of these volcanic events are poorly constrained (duration and magnitude). Consequently, the Greenland ice cores offer the opportunity to reliably reconstruct past Icelandic volcanism (duration, magnitude and frequency) due to their high-resolution, the proximity of Iceland to Greenland and subsequent increased likelihood of volcanic fallout deposits (tephra particles and sulphur aerosols) being preserved. However, both the high frequency of eruptions between 500-1250 AD and the geochemical similarity of Iceland’s volcanic centres present challenges in making the required robust geochemical correlations between the source volcano and the ice core records and ultimately reliably assessing the climatic-societal impacts of these eruptions.</p><p>To address this, we use two Greenland ice core records (TUNU2013 and B19) and undertake geochemical analysis on tephra from the volcanic events in the selected time window which have been detected and sampled using novel techniques (insoluble particle peaks and sulphur acidity peaks). Further geochemical analysis of proximal material enables robust correlations to be made between the events in the ice core records and their volcanic centres. The high-resolution of these polar archives provides a precise age for the event and when utilised alongside other proxies (i.e. sulphur aerosols), both the duration and magnitude of these eruptions can be constrained, and the climatic-societal impacts of these eruptions reliably assessed.</p>

scholarly journals The Ross Sea Dipole – temperature, snow accumulation and sea ice variability in the Ross Sea region, Antarctica, over the past 2700 years

2018 ◽  
Vol 14 (2) ◽  
pp. 193-214 ◽  
Author(s):  
Nancy A. N. Bertler ◽  
Howard Conway ◽  
Dorthe Dahl-Jensen ◽  
Daniel B. Emanuelsson ◽  
Mai Winstrup ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Ice Core ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Ice Age ◽  
West Antarctica ◽  
Isotopic Enrichment ◽  
The Past ◽  
Western Ross Sea

Abstract. High-resolution, well-dated climate archives provide an opportunity to investigate the dynamic interactions of climate patterns relevant for future projections. Here, we present data from a new, annually dated ice core record from the eastern Ross Sea, named the Roosevelt Island Climate Evolution (RICE) ice core. Comparison of this record with climate reanalysis data for the 1979–2012 interval shows that RICE reliably captures temperature and snow precipitation variability in the region. Trends over the past 2700 years in RICE are shown to be distinct from those in West Antarctica and the western Ross Sea captured by other ice cores. For most of this interval, the eastern Ross Sea was warming (or showing isotopic enrichment for other reasons), with increased snow accumulation and perhaps decreased sea ice concentration. However, West Antarctica cooled and the western Ross Sea showed no significant isotope temperature trend. This pattern here is referred to as the Ross Sea Dipole. Notably, during the Little Ice Age, West Antarctica and the western Ross Sea experienced colder than average temperatures, while the eastern Ross Sea underwent a period of warming or increased isotopic enrichment. From the 17th century onwards, this dipole relationship changed. All three regions show current warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea but increasing in the western Ross Sea. We interpret this pattern as reflecting an increase in sea ice in the eastern Ross Sea with perhaps the establishment of a modern Roosevelt Island polynya as a local moisture source for RICE.

scholarly journals Fabric measurement along the NEEM ice core, Greenland, and comparison with GRIP and NGRIP ice cores

2014 ◽  
Vol 8 (1) ◽  
pp. 307-335 ◽  
Author(s):  
M. Montagnat ◽  
N. Azuma ◽  
D. Dahl-Jensen ◽  
J. Eichler ◽  
S. Fujita ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Deformation Pattern ◽  
Bottom Part ◽  
Single Maximum ◽  
Shear Component ◽  
Climatic Transition ◽  
The Difference ◽  
The Impact ◽  
Good Agreement

Abstract. Fabric (distribution of crystallographic orientations) profile along the full NEEM ice core, Greenland, is presented in this work. Data were measured in the field by an Automatic Ice Texture Analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum at about 2300 m, which is typical of a deformation pattern mostly driven by uniaxial compression and simple shearing. A sharp increase in the fabric strengthening is observed at the Holocene to Wisconsin climatic transition. A similar strengthening, toward an anisotropic single maximum-type fabric, has been observed in several ice cores from Greenland and Antarctica, and can be attributed to a positive feedback between changes in ice viscosity at the climatic transition, and the impact of a shear component of stress. Centimeter scale abrupt texture (fabric and microstructure) variations are observed in the bottom part of the core. Their positions are in good agreement with the folding hypothesis used for a climatic reconstruction by Dahl-Jensen et al. (2013). Comparison is made to two others ice cores drilled along the same ridge; the GRIP ice core drilled at the summit of the ice sheet, and the NorthGRIP ice core, drilled 325 km to the NNW of the summit along the ridge, and 365 km upstream from NEEM. The fabric profile clearly reflects the increase in shear deformation when moving NW along the ridge from GRIP to NorthGRIP and NEEM. The difference in fabric profiles between NEEM and NorthGRIP also evidences a stronger lateral extension associated with a sharper ridge at NorthGRIP.

Forty years later: High resolution continuous flow analysis of the Dye3 ice core

2021 ◽  
Author(s):  
Helle Astrid Kjær ◽  
Margaret Harlan ◽  
Paul Vallelonga ◽  
Anders Svensson ◽  
Thomas Blunier ◽  
...  
Keyword(s):  
High Resolution ◽  
Forest Fires ◽  
Continuous Flow ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
The Core ◽  
Continuous Flow Analysis

<div><span><span>The Dye-3 ice core was drilled to bedrock at the Southern part of the central Greenland ice sheet (65°11'N, 43°50'W) in 1979-1981. The southern location is characterized by high accumulation rates compared to more central locations of the ice sheet. Since its drilling, numerous analyses of the core have been performed, and the ice has since been in freezer storage both in the USA and in Denmark.</span></span></div><div><span>In October and November 2019, the remaining ice, two mostly complete sections covering the depths of 1753–1820m and 1865–1918m of the Dye-3 core, were melted during a continuous flow analysis (CFA) campaign at the Physics of Ice, Climate, and Earth (PICE) group at the University of Copenhagen. The data represents both Holocene, Younger Dryas and Glacial sections (GS 5 to 12).</span></div><div> </div><div><span><span>The measured data consist chemistry and impurities contained in the ice, isotopes, as well as analysis of methane and other atmospheric gases. </span></span></div><div><span><span>The chemistry measurements include NH</span></span><span><span><sub>4</sub></span></span><span><span><sup>+</sup></span></span><span><span>, Ca</span></span><span><span><sup>2+</sup></span></span><span><span>, and Na</span></span><span><span><sup>+</sup></span></span><span><span> ions, which besides being influenced by transport, provide information about forest fires, wind-blown dust, and sea ice, respectively, as well as acidity, which aids in the identification of volcanic events contained in the core. The quantity and grain size distribution of insoluble particles was analyzed by means of an Abakus laser particle counter.</span></span></div><div> </div><div><span>We compare the new high-resolution CFA record of dye3 with previous analysis and thus evaluate the progress made over 40 years. Further we compare overlapping time periods with other central Greenland ice cores and discuss spatial patterns in relation to the presented climate proxies.</span></div>

Twentieth-Century Surface Temperature Trends in the Western Ross Sea, Antarctica: Evidence from a High-Resolution Ice Core

2012 ◽  
Vol 25 (10) ◽  
pp. 3629-3636 ◽  
Author(s):  
Kate E. Sinclair ◽  
Nancy A. N. Bertler ◽  
Tas D. van Ommen
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Ross Sea ◽  
Ice Core ◽  
Ice Cores ◽  
Southern Annular Mode ◽  
Temperature Record ◽  
Positive Trend ◽  
Sea Ice Extent ◽  
Western Ross Sea

Abstract A 125-yr ice core record of climate from the Whitehall Glacier ice divide provides exceptionally high-resolution stable isotope data from the northwest margin of the Ross Sea, Antarctica. This is the only proxy data available to extend the instrumental record of temperature in this region, where little is known about climate variability over the past two centuries. Using ECMWF Interim Re-Analysis (ERA-Interim) data, this study develops a precipitation-weighted δ18O-temperature transfer function of 0.62‰ °C−1, which is comparable to other proximal ice cores, such as Taylor, Talos, and Law Domes. Reconstructed mean annual temperatures show no significant change between 1882 and 2006. However, a decrease in cold season [April–September (AMJJAS)] temperatures of −1.59° ± 0.84°C decade−1 (at 90% confidence) is observed since 1979. This cooling trend is in contrast to a surface temperature record from Ross Island (Scott Base) where significant spring warming is observed. It is also coincident with a positive trend in the southern annular mode, which is linked to stronger southerly winds and increased sea ice extent and duration in the western Ross Sea.

Setup and first testing of Laser Ablation - ICP-MS measurements for high resolution chemical ice core analyses at University of Cambridge

2020 ◽  
Author(s):  
Helene Hoffmann ◽  
Eric Wolff ◽  
Jason Day ◽  
Mackenzie Grieman ◽  
Jack Humby ◽  
...  
Keyword(s):  
Laser Ablation ◽  
High Resolution ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Depth Resolution ◽  
Calibration Method ◽  
Last Interglacial ◽  
Measurement Sensitivity ◽  
Icp Ms

<p>The ice in the deepest and therefore oldest parts of polar ice cores is highly compressed and therefore annual layers, although potentially preserved, can be thinned to a millimeter level or even below. However, for many palaeoclimate studies these are the most interesting sections. Within the WACSWAIN project we aim to investigate the basal part of an ice core recently drilled to bedrock at the Skytrain ice rise in West Antarctica to obtain unique information on the state of the Filchner-Ronne ice shelf during the last interglacial. To achieve this we have set up a system to perform high resolution laser-ablation ICP-MS measurements using a cryocell stage on selected segments of the deepest parts of the ice cores.</p><p>Here we present first results of system performance including assessment of measurement sensitivity and precision with respect to analyses of the most relevant components, namely sodium, calcium and aluminium. We also report on the development and the performance of a matrix matched calibration method using flash-freezed water samples of known composition to convert relative signal intensities into concentrations. This especially focuses on homogeneity and reproducibility of the in-house produced standard. Finally, the results of laser ablation ICP-MS results are compared to parallel low resolution data from continuous flow analysis of the Skytrain core to evaluate the capabilities of the method in terms of improving depth resolution.</p>

scholarly journals Comparison of analytical methods used for measuring major ions in the EPICA Dome C (Antarctica) ice core

2002 ◽  
Vol 35 ◽  
pp. 299-305 ◽  
Author(s):  
Geneviève C. Littot ◽  
Robert Mulvaney ◽  
Regine Röthlisberger ◽  
Roberto Udisti ◽  
Eric W. Wolff ◽  
...  
Keyword(s):  
High Resolution ◽  
Ion Chromatography ◽  
Major Ions ◽  
Full Range ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
High Resolution Data ◽  
Wide Range

AbstractIn the past, ionic analyses of deep ice cores tended to consist of a few widely spaced measurements that indicated general trends in concentration. the ion-chromatographic methods widely used provide well-validated individual data, but are time-consuming. the development of continuous flow analysis (CFA) methods has allowed very rapid, high-resolution data to be collected in the field for a wide range of ions. In the European Project for Ice Coring in Antarctica (EPICA) deep ice-core drilling at Dome C, many ions have been measured at high resolution, and several have been analyzed by more than one method. the full range of ions has been measured in five different laboratories by ion chromatography (IC), at resolutions of 2.5–10 cm. In the field, CFA was used to measure the ions Na+, Ca2+, nitrate and ammonium. Additionally, a new semi-continuous in situ IC method, fast ion chromatography (FIC), was used to analyze sulphate, nitrate and chloride. Some data are now available to 788 m depth. In this paper we compare the data obtained by the three methods, and show that the rapid methods (CFA and FIC) give an excellent indication of trends in ionic data. Differences between the data from the different methods do occur, and in some cases these are genuine, being due to differences in speciation in the methods. We conclude that the best system for most deep ice-core analysis is a rapid system of CFA and FIC, along with in situ meltwater collection for analysis of other ions by IC, but that material should be kept aside for a regular check on analytical quality and for more detailed analysis of some sections.

scholarly journals An 83 000-year-old ice core from Roosevelt Island, Ross Sea, Antarctica

2020 ◽  
Vol 16 (5) ◽  
pp. 1691-1713 ◽  
Author(s):  
James E. Lee ◽  
Edward J. Brook ◽  
Nancy A. N. Bertler ◽  
Christo Buizert ◽  
Troy Baisden ◽  
...  
Keyword(s):  
Ross Sea ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
Age Difference ◽  
Last Deglaciation ◽  
Ice Streams ◽  
West Antarctic Ice Sheet ◽  
Annual Layer ◽  
West Antarctic

Abstract. In 2013 an ice core was recovered from Roosevelt Island, an ice dome between two submarine troughs carved by paleo-ice-streams in the Ross Sea, Antarctica. The ice core is part of the Roosevelt Island Climate Evolution (RICE) project and provides new information about the past configuration of the West Antarctic Ice Sheet (WAIS) and its retreat during the last deglaciation. In this work we present the RICE17 chronology, which establishes the depth–age relationship for the top 754 m of the 763 m core. RICE17 is a composite chronology combining annual layer interpretations for 0–343 m (Winstrup et al., 2019) with new estimates for gas and ice ages based on synchronization of CH4 and δ18Oatm records to corresponding records from the WAIS Divide ice core and by modeling of the gas age–ice age difference. Novel aspects of this work include the following: (1) an automated algorithm for multiproxy stratigraphic synchronization of high-resolution gas records; (2) synchronization using centennial-scale variations in methane for pre-anthropogenic time periods (60–720 m, 1971 CE to 30 ka), a strategy applicable for future ice cores; and (3) the observation of a continuous climate record back to ∼65 ka providing evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.

scholarly journals An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

2018 ◽  
Author(s):  
James E. Lee ◽  
Edward J. Brook ◽  
Nancy A. N. Bertler ◽  
Christo Buizert ◽  
Troy Baisden ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Ross Sea ◽  
Molecular Nitrogen ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
Ice Streams ◽  
West Antarctic Ice Sheet ◽  
Annual Layer ◽  
West Antarctic

Abstract. In 2013, an ice core was recovered from Roosevelt Island in the Ross Sea, Antarctica, as part of the Roosevelt Island Climate Evolution (RICE) project. Roosevelt Island is located between two submarine troughs carved by paleo-ice-streams. The RICE ice core provides new important information about the past configuration of the West Antarctic Ice Sheet and its retreat during the most recent deglaciation. In this work, we present the RICE17 chronology and discuss preliminary observations from the new records of methane, the isotopic composition of atmospheric molecular oxygen (δ18O-Oatm), the isotopic composition of atmospheric molecular nitrogen (δ15N-N2) and total air content (TAC). RICE17 is a composite chronology combining annual layer interpretations, gas synchronization, and firn modeling strategies in different sections of the core. An automated matching algorithm is developed for synchronizing the high-resolution section of the RICE gas records (60–720 m, 1971 CE to 30 ka) to corresponding records from the WAIS Divide ice core, while deeper sections are manually matched. Ice age for the top 343 m (2635 yr BP, before 1950 C.E.) is derived from annual layer interpretations and described in the accompanying paper by Winstrup et al. (2017). For deeper sections, the RICE17 ice age scale is based on the gas age constraints and the ice age-gas age offset estimated by a firn densification model. Novel aspects of this work include: 1) stratigraphic matching of centennial-scale variations in methane for pre-anthropogenic time periods, a strategy which will be applicable for developing precise chronologies for future ice cores, 2) the observation of centennial-scale variability in methane throughout the Holocene which suggests that similar variations during the late preindustrial period need not be anthropogenic, and 3) the observation of continuous climate records dating back to ∼ 65 ka which provide evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.

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