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

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.

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

10.5194/egusphere-egu21-11820 ◽

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>The Dye-3 ice core was drilled to bedrock at the Southern part of the central Greenland ice sheet (65&#176;11'N, 43&#176;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.</div><div>In October and November 2019, the remaining ice, two mostly complete sections covering the depths of 1753&#8211;1820m and 1865&#8211;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).</div><div>&#160;</div><div>The measured data consist chemistry and impurities contained in the ice, isotopes, as well as analysis of methane and other atmospheric gases.&#160;</div><div>The chemistry measurements include NH4+, Ca2+, and Na+&#160;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.</div><div>&#160;</div><div>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.</div>

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Continuous and High-Resolution Ice-Core Analysis (Abstract)

Annals of Glaciology ◽

10.3189/s026030550000450x ◽

1988 ◽

Vol 10 ◽

pp. 204-204

Author(s):

C.U. Hammer

Keyword(s):

High Resolution ◽

Seasonal Changes ◽

Ice Core ◽

Ice Cores ◽

Core Analysis ◽

High Resolution Measurement ◽

Resolution Measurement ◽

Core Components ◽

Solid Liquid

The aim of this paper is to evaluate and exemplify the potential of continuous and high-resolution ice-core analysis in atmospheric-climatic research.At present only a few ice-core components of current interest can be measured continuously with high resolution along the cores. In this paper, the techniques of in-situ or “in the laboratory” continuous high-resolution measurement of solid-liquid electrical conductivity, pH, dust and anions will be presented and discussed. In particular, results from individual precipitation samples, seasonal changes, rare events, and the comparison of results from various Antarctic and Greenland ice cores will be discussed.

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Continuous (CFA) CH4 record of the Elbrus ice core, Caucasus (preliminary results)

10.5194/egusphere-egu2020-20586 ◽

2020 ◽

Author(s):

Diana Vladimirova ◽

Xavier Faïn ◽

Patrick Ginot ◽

Stanislav Kutuzov ◽

Vladimir Mikhalenko

Keyword(s):

High Resolution ◽

Optical Feedback ◽

Ice Core ◽

Flow Analysis ◽

Preliminary Results ◽

Mixing Ratios ◽

Enhanced Absorption ◽

Ice Core Record ◽

In Situ Production

Methane (CH4) is the third most powerful greenhouse gas. However, its warming potential is two orders of magnitude higher than of carbon dioxide and its residence time in the atmosphere is only 9.1 &#177; 0.9 years. It makes CH4 a good indicator of rapid climate variations both under natural conditions and due to the anthropogenic influence.The Elbrus ice core was drilled in 2009 on the Western Plato (43&#176;20&#8217;53.9&#8217;&#8217;N, 42&#176;25&#8217;36.0&#8217;&#8217;E) at elevation 5115 m a.s.l. It is 182 m long and is dated back to 280 &#177; 400 CE (Common Era). The CH4 mixing ratios were analyzed using a continuous flow analysis (CFA) system paired with optical-feedback cavity-enhanced absorption spectroscopy. The measurements campaign was organized at Institut des G&#233;osciences de l'Environnement (IGE), Grenoble, France. This is a first high-resolution mid-latitude CH4 record. The record aims to better constrain the past evolution of mid-latitude methane sources.Here we present preliminary results of the methane concentration measurements of the Elbrus ice core in high-resolution (CFA CH4 record). We observe in situ production (max level 2900 ppb) and a baseline. We inspect a potential origin of the multiple spikes in the high-resolution record. Supposedly, either an in-situ production in the dust-rich layers occurred or a gas dissolution in the melt layers took place. However, the possibility of in-situ production during continuous gas extraction has to be further studied. The identified melt layers can serve as an indicator of interrupted stable water isotopic signal and may be supportive in the regional temperature reconstructions based on the Elbrus ice core record. A cleaned off the spikes record is inspected for the natural variability of the CH4 baseline concentration related to the short-term climate and methane emissions variability.

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

10.5194/egusphere-egu2020-19625 ◽

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

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.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.

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Continuous and High-Resolution Ice-Core Analysis (Abstract)

Annals of Glaciology ◽

10.1017/s026030550000450x ◽

1988 ◽

Vol 10 ◽

pp. 204

Author(s):

C.U. Hammer

Keyword(s):

High Resolution ◽

Seasonal Changes ◽

Ice Core ◽

Ice Cores ◽

Core Analysis ◽

High Resolution Measurement ◽

Resolution Measurement ◽

Core Components ◽

Solid Liquid

The aim of this paper is to evaluate and exemplify the potential of continuous and high-resolution ice-core analysis in atmospheric-climatic research. At present only a few ice-core components of current interest can be measured continuously with high resolution along the cores. In this paper, the techniques of in-situ or “in the laboratory” continuous high-resolution measurement of solid-liquid electrical conductivity, pH, dust and anions will be presented and discussed. In particular, results from individual precipitation samples, seasonal changes, rare events, and the comparison of results from various Antarctic and Greenland ice cores will be discussed.

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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

Climate of the Past Discussions ◽

10.5194/cpd-7-1175-2011 ◽

2011 ◽

Vol 7 (2) ◽

pp. 1175-1193 ◽

Cited By ~ 1

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.

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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

Climate of the Past ◽

10.5194/cp-7-1001-2011 ◽

2011 ◽

Vol 7 (3) ◽

pp. 1001-1009 ◽

Cited By ~ 21

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.

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High resolution aerosol concentration data from the Greenland NorthGRIP and NEEM deep ice cores

10.5194/essd-2021-324 ◽

2021 ◽

Author(s):

Tobias Erhardt ◽

Matthias Bigler ◽

Urs Federer ◽

Gideo Gfeller ◽

Daiana Leuenberger ◽

...

Keyword(s):

High Resolution ◽

Continuous Flow ◽

Ice Core ◽

Historical Context ◽

Flow Analysis ◽

Ice Cores ◽

Deposition Flux ◽

Concentration Data ◽

Continuous Flow Analysis ◽

North Greenland

Abstract. Records of chemical impurities from ice cores enable us to reconstruct the past deposition of aerosols onto the polar ice sheets and alpine glaciers. Through that, they allow us to gain insight into changes of the source, transport and deposition processes that ultimately determine the deposition flux at the coreing location. However, the low concentrations of the aerosol species in the ice and the resulting high risk of contamination poses a formidable analytical challenge, especially if long, continuous and highly resolved records are needed. Continuous Flow Analysis, CFA, the continuous melting, decontamination and analysis of ice-core samples has mostly overcome this issue and has quickly become the de-facto standard to obtain high-resolution aerosol records from ice cores after its inception at the University of Bern in the mid 90s. Here we present continuous records of calcium (Ca2+), sodium (Na+), ammonium (NH4+), nitrate (NO3−1) and electrolytic conductivity at 1 mm depth resolution from the NGRIP (North Greenland Ice Core Project) and NEEM (North Greenland Eemian Ice Drilling) ice cores produced by the Bern Continuous Flow Analysis group in the years 2000 to 2011. Both of the records have previously been used in a number of studies but have never been published in the full 1 mm resolution. Alongside the 1 mm datasets we provide decadal averages, a detailed description of the methods, relevant references, an assessment of the quality of the data and its usable resolution. Along the way we will also give some historical context on the development of the Bern CFA system.

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Reconstructing Antarctic snow accumulation using nitrogen isotopes of nitrate

10.5194/egusphere-egu21-672 ◽

2021 ◽

Author(s):

Pete D. Akers ◽

Joël Savarino ◽

Nicolas Caillon ◽

Mark Curran ◽

Tas Van Ommen

Keyword(s):

Nitrogen Isotopes ◽

Full Range ◽

Ice Core ◽

Ice Cores ◽

Snow Accumulation ◽

East Antarctica ◽

Accumulation Rates ◽

Sea Levels ◽

Antarctic Snow ◽

Parallel Reconstruction

Precise Antarctic snow accumulation estimates are needed to understand past and future changes in global sea levels, but standard reconstructions using water isotopes suffer from competing isotopic effects external to accumulation. We present here an alternative accumulation proxy based on the post-depositional photolytic fractionation of nitrogen isotopes (d15N) in nitrate. On the high plateau of East Antarctica, sunlight penetrating the uppermost snow layers converts snow-borne nitrate into nitrogen oxide gas that can be lost to the atmosphere. This nitrate loss favors 14NO3- over 15NO3-, and thus the d15N of nitrate remaining in the snow will steadily increase until the nitrate is eventually buried beneath the reach of light. Because the duration of time until burial is dependent upon the rate of net snow accumulation, sites with lower accumulation rates have a longer burial wait and thus higher d15N values. A linear relationship (r2 = 0.86) between d15N and net accumulation-1 is calculated from over 120 samples representing 105 sites spanning East Antarctica. These sites largely encompass the full range of snow accumulation rates observed in East Antarctica, from 25 kg m-2 yr-1 at deep interior sites to >400 kg m-2 yr-1 at near coastal sites. We apply this relationship as a transfer function to an Aurora Basin ice core to produce a 700-year record of accumulation changes. Our nitrate-based estimate compares very well with a parallel reconstruction for Aurora Basin that uses volcanic horizons and ice-penetrating radar. Continued improvements to our database may enable precise independent estimates of millennial-scale accumulation changes using deep ice cores such as EPICA Dome C and Beyond EPICA-Oldest Ice.

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Calculating uncertainty for the RICE ice core continuous flow analysis water isotope record

Atmospheric Measurement Techniques ◽

10.5194/amt-11-4725-2018 ◽

2018 ◽

Vol 11 (8) ◽

pp. 4725-4736 ◽

Cited By ~ 2

Author(s):

Elizabeth D. Keller ◽

W. Troy Baisden ◽

Nancy A. N. Bertler ◽

B. Daniel Emanuelsson ◽

Silvia Canessa ◽

...

Keyword(s):

High Resolution ◽

Continuous Flow ◽

Ice Core ◽

Flow Analysis ◽

Calibration Error ◽

Data Set ◽

Total Uncertainty ◽

Continuous Flow Analysis ◽

Uncertainty Estimates ◽

Water Isotope

Abstract. We describe a systematic approach to the calibration and uncertainty estimation of a high-resolution continuous flow analysis (CFA) water isotope (δ2H, δ18O) record from the Roosevelt Island Climate Evolution (RICE) Antarctic ice core. Our method establishes robust uncertainty estimates for CFA δ2H and δ18O measurements, comparable to those reported for discrete sample δ2H and δ18O analysis. Data were calibrated using a time-weighted two-point linear calibration with two standards measured both before and after continuously melting 3 or 4 m of ice core. The error at each data point was calculated as the quadrature sum of three factors: Allan variance error, scatter over our averaging interval (error of the variance) and calibration error (error of the mean). Final mean total uncertainty for the entire record is δ2H=0.74 ‰ and δ18O=0.21 ‰. Uncertainties vary through the data set and were exacerbated by a range of factors, which typically could not be isolated due to the requirements of the multi-instrument CFA campaign. These factors likely occurred in combination and included ice quality, ice breaks, upstream equipment failure, contamination with drill fluid and leaks or valve degradation. We demonstrate that our methodology for documenting uncertainty was effective across periods of uneven system performance and delivered a significant achievement in the precision of high-resolution CFA water isotope measurements.

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