scholarly journals On the occurrence of annual layers in Dome Fuji ice core early Holocene ice

2015 ◽  
Vol 11 (2) ◽  
pp. 805-830
Author(s):  
A. Svensson ◽  
S. Fujita ◽  
M. Bigler ◽  
M. Braun ◽  
R. Dallmayr ◽  
...  
Keyword(s):  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Early Holocene ◽  
High Temporal Resolution ◽  
High Accumulation ◽  
Antarctic Plateau ◽  
Annual Layer ◽  
Dronning Maud Land ◽  
Seasonal Signal

Abstract. Whereas ice cores from high accumulation sites in coastal Antarctica clearly demonstrate annual layering, it is debated whether a seasonal signal is also preserved in ice cores from lower accumulation sites further inland and particularly on the East Antarctic Plateau. In this study, we examine five metres of early Holocene ice from the Dome Fuji (DF) ice core in high temporal resolution by continuous flow analysis. The ice was continuously analyzed for concentrations of dust, sodium, ammonium, liquid conductivity, and water isotopic composition. Furthermore, a dielectric profiling was performed on the solid ice. In most of the analyzed ice, the multi-parameter impurity dataset appears to resolve the seasonal variability although the identification of annual layers is not always unambiguous. A layer counting based on the same principles as those previously applied to the Greenland NGRIP and the Antarctic EPICA Dronning Maud Land (EDML) ice cores leads to a mean annual layer thickness for the DF ice of 3.0 ± 0.3 cm that compares well to existing estimates. The measured DF section is linked to the EDML ice core through a characteristic pattern of three significant acidity peaks that are present in both cores. The corresponding section of the EDML ice core has recently been dated by annual layer counting and the number of years identified independently in the two cores agree within error estimates. We therefore conclude that, to first order, the annual signal is preserved in this section of the DF core. This case study demonstrates the feasibility of determining annually deposited strata on the central Eastern Antarctic Plateau. It also opens the possibility of resolving annual layers in the Eemian section of the DF ice core where the accumulation is estimated to have been greater than in the Holocene.

scholarly journals On the occurrence of annual layers in Dome Fuji ice core early Holocene ice

2015 ◽  
Vol 11 (9) ◽  
pp. 1127-1137 ◽  
Author(s):  
A. Svensson ◽  
S. Fujita ◽  
M. Bigler ◽  
M. Braun ◽  
R. Dallmayr ◽  
...  
Keyword(s):  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Early Holocene ◽  
High Temporal Resolution ◽  
High Accumulation ◽  
Data Set ◽  
Antarctic Plateau ◽  
Annual Layer

Abstract. Whereas ice cores from high-accumulation sites in coastal Antarctica clearly demonstrate annual layering, it is debated whether a seasonal signal is also preserved in ice cores from lower-accumulation sites further inland and particularly on the East Antarctic Plateau. In this study, we examine 5 m of early Holocene ice from the Dome Fuji (DF) ice core at a high temporal resolution by continuous flow analysis. The ice was continuously analysed for concentrations of dust, sodium, ammonium, liquid conductivity, and water isotopic composition. Furthermore, a dielectric profiling was performed on the solid ice. In most of the analysed ice, the multi-parameter impurity data set appears to resolve the seasonal variability although the identification of annual layers is not always unambiguous. The study thus provides information on the snow accumulation process in central East Antarctica. A layer counting based on the same principles as those previously applied to the NGRIP (North Greenland Ice core Project) and the Antarctic EPICA (European Project for Ice Coring in Antarctica) Dronning Maud Land (EDML) ice cores leads to a mean annual layer thickness for the DF ice of 3.0 ± 0.3 cm that compares well to existing estimates. The measured DF section is linked to the EDML ice core through a characteristic pattern of three significant acidity peaks that are present in both cores. The corresponding section of the EDML ice core has recently been dated by annual layer counting and the number of years identified independently in the two cores agree within error estimates. We therefore conclude that, to first order, the annual signal is preserved in this section of the DF core. This case study demonstrates the feasibility of determining annually deposited strata on the central East Antarctic Plateau. It also opens the possibility of resolving annual layers in the Eemian section of Antarctic ice cores where the accumulation is estimated to have been greater than in the Holocene.

scholarly journals New LA-ICP-MS cryocell and calibration technique for sub-millimeter analysis of ice cores

2015 ◽  
Vol 61 (226) ◽  
pp. 233-242 ◽  
Author(s):  
Sharon B. Sneed ◽  
Paul A. Mayewski ◽  
W.G. Sayre ◽  
Michael J. Handley ◽  
Andrei V. Kurbatov ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Chemical Constituents ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Calibration Technique ◽  
Inductively Coupled ◽  
Annual Layer ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

AbstractIce cores provide a robust reconstruction of past climate. However, development of timescales by annual-layer counting, essential to detailed climate reconstruction and interpretation, on ice cores collected at low-accumulation sites or in regions of compressed ice, is problematic due to closely spaced layers. Ice-core analysis by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) provides sub-millimeter-scale sampling resolution (on the order of 100 μm in this study) and the low detection limits (ng L−1) necessary to measure the chemical constituents preserved in ice cores. We present a newly developed cryocell that can hold a 1 m long section of ice core, and an alternative strategy for calibration. Using ice-core samples from central Greenland, we demonstrate the repeatability of multiple ablation passes, highlight the improved sampling resolution, verify the calibration technique and identify annual layers in the chemical profile in a deep section of an ice core where annual layers have not previously been identified using chemistry. In addition, using sections of cores from the Swiss/Italian Alps we illustrate the relationship between Ca, Na and Fe and particle concentration and conductivity, and validate the LA-ICP-MS Ca profile through a direct comparison with continuous flow analysis results.

scholarly journals Annual-layer determinations and 167 year records of past climate of H72 ice core in east Dronning Maud Land, Antarctica

2002 ◽  
Vol 35 ◽  
pp. 471-479 ◽  
Author(s):  
Fumihiko Nishio ◽  
Teruo Furukawa ◽  
Gen Hashida ◽  
Makoto Igarashi ◽  
Takao Kameda ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Ice Cores ◽  
Surface Mass Balance ◽  
Tritium Content ◽  
Surface Mass ◽  
Annual Layer ◽  
Dronning Maud Land ◽  
Annual Resolution ◽  
Continuous Accumulation

AbstractTo determine annual layers for reconstructing the past environment at annual resolution from ice cores, we employed snow-stake data back to 1972, tritium content, solid electrical conductivity measurements (ECM) and stratigraphic properties for the 73m ice core at the H72 site, east Dronning Maud Land, Antarctica. the average annual surface mass balance at H72 is 307 mma–1w.e. during the last 27 years from continuous accumulation data, 317 mma–1 w.e. according to the densification model and 311 mma–1 w.e. according to the average surface mass balance for 167 years based on annual-layer counting. the ECM age is closely coincident with tritium age, and corresponds with the snow-stake record back to AD 1972 from the surface to 15 m depth. the H72 ice core is dated as AD 1831by ECMat 73.16 mdepth.The time series of yearly surface mass balance at H72 shows an almost constant 311 mm a–1 w.e. for the last 167 years. the oxygen-isotope records indicate a significant trend to lower values, with negative gradient of 1.7% (100 years)–1.

Representativeness of decadal-scale climate signals in ice-core aerosol records

2020 ◽  
Author(s):  
Tobias Erhardt ◽  
Camilla Jensen ◽  
Maria Hörhold ◽  
Hubertus Fischer
Keyword(s):  
High Resolution ◽  
Time Scales ◽  
Decadal Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Aerosol Deposition ◽  
High Temporal Resolution ◽  
Annual Layer ◽  
Decadal Scale ◽  
Climate Signals

<p>Records of past aerosol deposition to the polar ice sheets have enabled us to study variability in different parts of the earth system in great temporal detail over past glacial cycles. Furthermore, the high temporal resolution of ice-core aerosol records has been the basis for precise dating of climate records using annual layer counting. Nonetheless, the intermittent character of show deposition and especially the redistribution of snow on the surface of the ice sheet intrinsically affects the preservation of climate signals in the ice. This strongly limits how representative a climate record from a single ice core can be. It has been well established that even though seasonal variability might be preserved in an ice-core aerosol record, the inter annual variability of that record is different from a different core from the same site.</p><p>Until now most of the investigations have focused on inter annual representatives. This is mostly due to limited sample availability as multiple long records are needed for investigations on longer time scales. However, with the prospect of new high-resolution records over the Holocene from the EastGRIP ice core, understanding the representativeness of this record on decadal time scales is an important question. To tackle this problem, we use high-resolution aerosol records from multiple closely spaced ice cores from the EastGRIP deep ice core drill site. The records approximately cover the last millennium and are sub-seasonally resolved enabling the study of interannual to decadal variability over multiple aerosol species. All records are dated using annual layer counting and cross dating to the EastGRIP deep ice core using volcanic match points. In the presented pilot study, we focus on records of sea-salt and dust related aerosol species as well as on episodic aerosol signals from volcanos and wildfires.</p>

scholarly journals An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the 1450s CE eruption of Kuwae, Vanuatu

2012 ◽  
Vol 8 (6) ◽  
pp. 1929-1940 ◽  
Author(s):  
C. T. Plummer ◽  
M. A. J. Curran ◽  
T D. van Ommen ◽  
S. O. Rasmussen ◽  
A. D. Moy ◽  
...  
Keyword(s):  
Climate Models ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
East Antarctica ◽  
External Information ◽  
Climatic Effects ◽  
High Accumulation ◽  
Annual Layer ◽  
Volcanic Events

Abstract. Volcanic eruptions are an important cause of natural climate variability. In order to improve the accuracy of climate models, precise dating and magnitude of the climatic effects of past volcanism are necessary. Here we present a 2000-yr record of Southern Hemisphere volcanism recorded in ice cores from the high accumulation Law Dome site, East Antarctica. The ice cores were analysed for a suite of chemistry signals and are independently dated via annual layer counting, with 11 ambiguous years at 23 BCE, which has presently the lowest error of all published long Antarctic ice cores. Independently dated records are important to avoid circular dating where volcanic signatures are assigned a date from some external information rather than using the date it is found in the ice core. Forty-five volcanic events have been identified using the sulphate chemistry of the Law Dome record. The low dating error and comparison with the NGRIP (North Greenland Ice Core Project) volcanic records (on the GICC05 timescale) suggest Law Dome is the most accurately dated Antarctic volcanic dataset, which will improve the dating of individual volcanic events and potentially allow better correlation between ice core records, leading to improvements in global volcanic forcing datasets. One of the most important volcanic events of the last two millennia is the large 1450s CE event, usually assigned to the eruption of Kuwae, Vanuatu. In this study, we review the evidence surrounding the presently accepted date for this event, and make the case that two separate eruptions have caused confusion in the assignment of this event. Volcanic sulphate deposition estimates are important for modelling the climatic response to eruptions. The largest volcanic sulphate events in our record are dated at 1458 CE (Kuwae?, Vanuatu), 1257 and 422 CE (unidentified).

scholarly journals A new continuous high-resolution detection system for sulphate in ice cores

2007 ◽  
Vol 45 ◽  
pp. 178-182 ◽  
Author(s):  
Matthias Bigler ◽  
Anders Svensson ◽  
Jørgen Peder Steffensen ◽  
Patrik Kaufmann
Keyword(s):  
Detection System ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Barium Sulphate ◽  
High Temporal Resolution ◽  
Continuous Flow Analysis ◽  
Explosive Volcanic Eruptions ◽  
Analysis System

AbstractSulphate (SO42–) is a major ion found in polar ice cores and is related to different aerosol sources and processes. Explosive volcanic eruptions, even far away, can cause distinct sulphate peaks in ice core records. Thus, a robust sulphate detection system which is suitable for fieldwork and which enables the measurement of sulphate at high temporal resolution is of great interest. In this study, we present the adaptation of a new continuous flow analysis system for sulphate that is based on a spectrophotometric method using dimethylsulfonazo III and an inline reactor column containing barium sulphate particles. The method shows a detection limit of ∽70 ng g–1 and a linear range up to at least 3000 ng g–1. It is simple, robust and less prone to interferences compared to the previously used method.

scholarly journals The WAIS-Divide deep ice core WD2014 chronology – Part 2: Methane synchronization (68–31 ka BP) and the gas age-ice age difference

2014 ◽  
Vol 10 (4) ◽  
pp. 3537-3584 ◽  
Author(s):  
C. Buizert ◽  
K. M. Cuffey ◽  
J. P. Severinghaus ◽  
D. Baggenstos ◽  
T. J. Fudge ◽  
...  
Keyword(s):  
Ice Core ◽  
Impurity Content ◽  
Ice Cores ◽  
Ice Age ◽  
Age Difference ◽  
Atmospheric Methane ◽  
High Accumulation ◽  
West Antarctic Ice Sheet ◽  
Annual Layer ◽  
West Antarctic

Abstract. The West Antarctic Ice Sheet (WAIS)-Divide ice core (WAIS-D) is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ∼68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8–31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WAIS-D gas age-ice age difference (Δage) using a combination of firn densification modeling, ice flow modeling, and a dataset of δ15N-N2, a proxy for past firn column thickness. The largest Δage at WAIS-D occurs during the last glacial maximum, and is 525 ± 100 years. Internally consistent solutions can only be found when assuming little-to-no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WAIS-D chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard-Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu speleothem record. The small Δage at WAIS-D provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the bipolar "seesaw".

scholarly journals Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low-accumulation conditions

2017 ◽  
Vol 13 (12) ◽  
pp. 1815-1830 ◽  
Author(s):  
Kévin Fourteau ◽  
Xavier Faïn ◽  
Patricia Martinerie ◽  
Amaëlle Landais ◽  
Alexey A. Ekaykin ◽  
...  
Keyword(s):  
Ice Core ◽  
Flow Analysis ◽  
Atmospheric Composition ◽  
Atmospheric Variability ◽  
High Accumulation ◽  
Antarctic Plateau ◽  
Mixing Ratios ◽  
Gas Trapping ◽  
Continuous Flow Analysis ◽  
Concentration Changes

Abstract. We investigate for the first time the loss and alteration of past atmospheric information from air trapping mechanisms under low-accumulation conditions through continuous CH4 (and CO) measurements. Methane concentration changes were measured over the Dansgaard–Oeschger event 17 (DO-17,  ∼  60 000 yr BP) in the Antarctic Vostok 4G-2 ice core. Measurements were performed using continuous-flow analysis combined with laser spectroscopy. The results highlight many anomalous layers at the centimeter scale that are unevenly distributed along the ice core. The anomalous methane mixing ratios differ from those in the immediate surrounding layers by up to 50 ppbv. This phenomenon can be theoretically reproduced by a simple layered trapping model, creating very localized gas age scale inversions. We propose a method for cleaning the record of anomalous values that aims at minimizing the bias in the overall signal. Once the layered-trapping-induced anomalies are removed from the record, DO-17 appears to be smoother than its equivalent record from the high-accumulation WAIS Divide ice core. This is expected due to the slower sinking and densification speeds of firn layers at lower accumulation. However, the degree of smoothing appears surprisingly similar between modern and DO-17 conditions at Vostok. This suggests that glacial records of trace gases from low-accumulation sites in the East Antarctic plateau can provide a better time resolution of past atmospheric composition changes than previously expected. We also developed a numerical method to extract the gas age distributions in ice layers after the removal of the anomalous layers based on comparison with a weakly smoothed record. It is particularly adapted for the conditions of the East Antarctic plateau, as it helps to characterize smoothing for a large range of very low-temperature and low-accumulation conditions.

scholarly journals The WAIS Divide deep ice core WD2014 chronology – Part 1: Methane synchronization (68–31 ka BP) and the gas age–ice age difference

2015 ◽  
Vol 11 (2) ◽  
pp. 153-173 ◽  
Author(s):  
C. Buizert ◽  
K. M. Cuffey ◽  
J. P. Severinghaus ◽  
D. Baggenstos ◽  
T. J. Fudge ◽  
...  
Keyword(s):  
Ice Core ◽  
Impurity Content ◽  
Ice Cores ◽  
Ice Age ◽  
Age Difference ◽  
Atmospheric Methane ◽  
High Accumulation ◽  
Data Set ◽  
Annual Layer ◽  
West Antarctic

Abstract. The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ∼68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8–31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WD gas age–ice age difference (Δage) using a combination of firn densification modeling, ice-flow modeling, and a data set of δ15N-N2, a proxy for past firn column thickness. The largest Δage at WD occurs during the Last Glacial Maximum, and is 525 ± 120 years. Internally consistent solutions can be found only when assuming little to no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WD chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard–Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu Cave speleothem record. The small Δage at WD provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the "bipolar seesaw".

scholarly journals Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low accumulation conditions

2017 ◽  
Author(s):  
Kévin Fourteau ◽  
Xavier Faïn ◽  
Patricia Martinerie ◽  
Amaëlle Landais ◽  
Alexey A. Ekaykin ◽  
...  
Keyword(s):  
Ice Core ◽  
Flow Analysis ◽  
Atmospheric Composition ◽  
Atmospheric Variability ◽  
High Accumulation ◽  
Antarctic Plateau ◽  
Mixing Ratios ◽  
Gas Trapping ◽  
Continuous Flow Analysis ◽  
Concentration Changes

Abstract. We investigate for the first time through continuous measurements the loss and alteration of past atmospheric information from air trapping mechanisms under low accumulation conditions. Methane concentration changes were measured over the Dansgaard-Oeschger event 17 (D0-17, ~ 60,000 yrBP) in the Antarctic Vostok 4G-2 ice core. Measurements were performed using continuous-flow analysis combined with laser spectroscopy. The results highlight many anomalous layers at the centimeter scale, unevenly distributed along the ice core. The anomalous methane mixing ratios differ from those in the immediate surrounding layers by up to 50 ppbv. This phenomenon can be theoretically reproduced by a simple layered trapping model, creating very localized gas age scale inversions. We propose a method for cleaning the record of anomalous values which aims at minimizing the bias in the overall signal. Once the layered-trapping induced anomalies are removed from the record, the DO-17 appears to be smoother than its equivalent record from the high accumulation WAIS Divide ice core. This is expected due to the slower sinking and densification speeds of firn layers at lower accumulation. However and surprisingly, the degree of smoothing appears similar between modern and DO-17 conditions at Vostok. This suggests that glacial records of trace gases from low accumulation sites in the East Antarctic plateau can provide a better time resolution of past atmospheric composition changes than usually expected. We also developed a method to extract the gas age distributions in ice layers that can be applied even for sites without firn-air measurements. It is particularly adapted for the conditions of the East Antarctic plateau, as it helps to characterize smoothing for a large range of very low temperature and accumulation conditions.

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