Continuous Flow Analysis of Total Organic Carbon in Polar Ice Cores

Abstract. Water isotopes in ice cores are used as a climate proxy for local temperature and regional atmospheric circulation as well as evaporative conditions in moisture source regions. Traditional measurements of water isotopes have been achieved using magnetic sector isotope ratio mass spectrometry (IRMS). However, a number of recent studies have shown that laser absorption spectrometry (LAS) performs as well or better than IRMS. The new LAS technology has been combined with continuous-flow analysis (CFA) to improve data density and sample throughput in numerous prior ice coring projects. Here, we present a comparable semi-automated LAS-CFA system for measuring high-resolution water isotopes of ice cores. We outline new methods for partitioning both system precision and mixing length into liquid and vapor components – useful measures for defining and improving the overall performance of the system. Critically, these methods take into account the uncertainty of depth registration that is not present in IRMS nor fully accounted for in other CFA studies. These analyses are achieved using samples from a South Pole firn core, a Greenland ice core, and the West Antarctic Ice Sheet (WAIS) Divide ice core. The measurement system utilizes a 16-position carousel contained in a freezer to consecutively deliver ∼  1 m  ×  1.3 cm2 ice sticks to a temperature-controlled melt head, where the ice is converted to a continuous liquid stream and eventually vaporized using a concentric nebulizer for isotopic analysis. An integrated delivery system for water isotope standards is used for calibration to the Vienna Standard Mean Ocean Water (VSMOW) scale, and depth registration is achieved using a precise overhead laser distance device with an uncertainty of ±0.2  mm. As an added check on the system, we perform inter-lab LAS comparisons using WAIS Divide ice samples, a corroboratory step not taken in prior CFA studies. The overall results are important for substantiating data obtained from LAS-CFA systems, including optimizing liquid and vapor mixing lengths, determining melt rates for ice cores with different accumulation and thinning histories, and removing system-wide mixing effects that are convolved with the natural diffusional signal that results primarily from water molecule diffusion in the firn column.

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Continuous Flow Analysis Method for Determination of Dissolved Reactive Phosphorus in Ice Cores

Environmental Science & Technology ◽

10.1021/es402274z ◽

2013 ◽

Vol 47 (21) ◽

pp. 12325-12332 ◽

Cited By ~ 9

Author(s):

Helle Astrid Kjær ◽

Paul Vallelonga ◽

Anders Svensson ◽

Magnus Elleskov L. Kristensen ◽

Catalin Tibuleac ◽

...

Keyword(s):

Continuous Flow ◽

Flow Analysis ◽

Ice Cores ◽

Analysis Method ◽

Continuous Flow Analysis ◽

Dissolved Reactive Phosphorus ◽

Reactive Phosphorus

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Improved Methodologies for Continuous Flow Analysis of Stable Water Isotopes in Ice Cores

10.5194/amt-2016-118 ◽

2016 ◽

Cited By ~ 2

Author(s):

Tyler R. Jones ◽

James W. C. White ◽

Eric J. Steig ◽

Bruce H. Vaughn ◽

Valerie Morris ◽

...

Keyword(s):

Continuous Flow ◽

Ice Core ◽

Flow Analysis ◽

Ice Cores ◽

Isotope Ratio Mass Spectrometry ◽

Isotopic Analysis ◽

Water Isotopes ◽

Mixing Length ◽

Stable Water Isotopes ◽

Continuous Flow Analysis

Abstract. Water isotopes in ice cores are used as a climate proxy for local temperature and regional atmospheric circulation as well as evaporative conditions in moisture source regions. Traditional measurements of water isotopes have been achieved using magnetic sector isotope ratio mass spectrometry (IRMS). However, a number of recent studies have shown that laser absorption spectrometers (LAS) perform as well or better than IRMS. The new LAS technology has been combined with continuous flow analysis (CFA) to improve data density and sample throughput in numerous prior ice coring projects. Here, we present a comparable semi-automated LAS-CFA system for measuring high-resolution water isotopes of ice cores. We outline new methods for partitioning both system uncertainty and system mixing length into liquid and vapor components – useful measures for defining and improving the overall performance of the system. Critically, our methods take into account the uncertainty of depth registration that is not present in IRMS nor fully accounted for in other CFA studies. We also explain a method for introducing consecutive sections of isotopically distinct ice at the melt head to define the system-wide mixing length. These analyses are achieved using samples from a South Pole firn core, a Greenland ice core, and the WAIS Divide ice core. The measurement system utilizes a 16-position carousel contained in a freezer to consecutively deliver ~ 1 m × 1.3 cm2 ice sticks to a temperature controlled melt head, where the ice is converted to a continuous liquid stream, and eventually vaporized using a concentric nebulizer for isotopic analysis. An integrated delivery system for water isotope standards is used for calibration to the VSMOW-SLAP scale and depth registration is achieved using a precise overhead laser distance device with an uncertainty of ±0.2 mm. As an added check on our system, we perform inter-lab LAS comparisons using WAIS Divide ice samples, a corroboratory step not taken in prior CFA studies. The overall results are important for substantiating data obtained from LAS-CFA systems, including optimizing liquid and vapor mixing lengths, determining melt rates for ice cores with different accumulation and thinning histories, and removing system-wide mixing effects that are convolved with the natural diffusional signal that results primarily from water molecule diffusion in the firn column.

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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><span><span>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.</span></span></div><div><span>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).</span></div><div>&#160;</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.&#160;</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>&#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.</span></span></div><div>&#160;</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>

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Optimization of High-Resolution Continuous Flow Analysis for Transient Climate Signals in Ice Cores

Environmental Science & Technology ◽

10.1021/es200118j ◽

2011 ◽

Vol 45 (10) ◽

pp. 4483-4489 ◽

Cited By ~ 56

Author(s):

Matthias Bigler ◽

Anders Svensson ◽

Ernesto Kettner ◽

Paul Vallelonga ◽

Maibritt E. Nielsen ◽

...

Keyword(s):

High Resolution ◽

Continuous Flow ◽

Flow Analysis ◽

Ice Cores ◽

Continuous Flow Analysis ◽

Climate Signals

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Continuous Flow Analysis of Labile Iron in Ice-Cores

Environmental Science & Technology ◽

10.1021/es3047087 ◽

2013 ◽

Vol 47 (9) ◽

pp. 4416-4425 ◽

Cited By ~ 4

Author(s):

William T. Hiscock ◽

Hubertus Fischer ◽

Matthias Bigler ◽

Gideon Gfeller ◽

Daiana Leuenberger ◽

...

Keyword(s):

Continuous Flow ◽

Flow Analysis ◽

Ice Cores ◽

Continuous Flow Analysis ◽

Labile Iron

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High-resolution continuous flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-12081-2014 ◽

2014 ◽

Vol 7 (12) ◽

pp. 12081-12124 ◽

Cited By ~ 1

Author(s):

B. D. Emanuelsson ◽

W. T. Baisden ◽

N. A. N. Bertler ◽

E. D. Keller ◽

V. Gkinis

Keyword(s):

Response Time ◽

Laser Spectroscopy ◽

Temporal Resolution ◽

Continuous Flow ◽

Ice Core ◽

Flow Analysis ◽

Ice Cores ◽

Flow Measurements ◽

Continuous Flow Analysis ◽

Δ18o And Δd

Abstract. Here we present an experimental setup for water stable isotopes (δ18O and δD) continuous flow measurements. It is the first continuous flow laser spectroscopy system that is using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research – LGR) in combination with an evaporation unit to continuously analyze sample from an ice core. A Water Vapor Isotopic Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to: (1) increase the temporal resolution by reducing the response time (2) enable measurements on several water standards, and (3) to reduce the influence from memory effects. While this setup was designed for the Continuous Flow Analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. The modified setup provides a shorter response time (~54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the modified setup has a reduced memory effect. Stability tests comparing the modified WVISS and WVISS setups were performed and Allan deviations (σAllan) were calculated to determine precision at different averaging times. For the 2013 modified setup the precision after integration times of 103 s are 0.060 and 0.070‰ for δ18O and δD, respectively. For the WVISS setup the corresponding σAllan values are 0.030, 0.060 and 0.043‰ for δ18O, δD and δ17O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042‰ after 103 s for δ18O, δD and δ17O, respectively. Both the modified setups and WVISS setup are influenced by instrumental drift with δ18O being more drift sensitive than δD. The σAllan values for δ18O of 0.30 and 0.18‰ for the modified (2013) and WVISS setup, respectively after averaging times of 104 s (2.78 h). The Isotopic Water Analyzer (IWA)-modified WVISS setup used during the 2013 Roosevelt Island Climate Evolution (RICE) ice core processing campaign achieved high precision measurements, in particular for δD, with high temporal resolution for the upper part of the core, where a seasonally resolved isotopic signal is preserved.

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