scholarly journals Antarctic Anion Glaciochemistry (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 354-354
Author(s):  
Michael M. Herron
Keyword(s):  
Fossil Fuel ◽  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
Scale Height ◽  
Solar Modulation ◽  
Fossil Fuel Combustion ◽  
Marine Aerosol ◽  
Major Anions

Snow and ice-core samples from a number of sites in Antarctica and Greenland have been analyzed for the major anions Cl−, NO3−, and SO42- by ion chromatography. Reproducibility on adjacent core or pit samples is ±10% at the 95% confidence level. Chloride is of marine origin except following some major volcanic eruptions. Chloride concentrations decrease exponentially with increasing site elevation with a scale height of about 1.5 km. For sites of comparable elevation, Antarctic Cl− concentrations are only slightly higher than in Greenland. Sulfate concentrations, corrected for the marine aerosol contribution, show an inverse dependence on snow accumulation rate. For sites of comparable accumulation rate, Greenland concentrations exceed those in Antarctica by a factor of 2 to 3. Nitrate concentrations also decrease with increasing accumulation rate and for comparable sites Greenland NO3− concentrations are a factor of 2 higher than in Antarctica. There is no evidence of solar modulation or supernova perturbation of Greenland NO3− concentrations. The Byrd deep core is shown to have distinct seasonal variations in Cl− and SO42- that may be used for dating. In addition, the Byrd core contains volcanic signals similar to those found in Greenland. Recent Greenland snow contains about 4 times as much SO42- and 2 to 3 times as much NO3− as is found in older ice due to modern fossil fuel combustion.

scholarly journals Antarctic Anion Glaciochemistry (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 354
Author(s):  
Michael M. Herron
Keyword(s):  
Fossil Fuel ◽  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
Scale Height ◽  
Solar Modulation ◽  
Fossil Fuel Combustion ◽  
Marine Aerosol ◽  
Major Anions

Snow and ice-core samples from a number of sites in Antarctica and Greenland have been analyzed for the major anions Cl−, NO3 −, and SO4 2- by ion chromatography. Reproducibility on adjacent core or pit samples is ±10% at the 95% confidence level. Chloride is of marine origin except following some major volcanic eruptions. Chloride concentrations decrease exponentially with increasing site elevation with a scale height of about 1.5 km. For sites of comparable elevation, Antarctic Cl− concentrations are only slightly higher than in Greenland. Sulfate concentrations, corrected for the marine aerosol contribution, show an inverse dependence on snow accumulation rate. For sites of comparable accumulation rate, Greenland concentrations exceed those in Antarctica by a factor of 2 to 3. Nitrate concentrations also decrease with increasing accumulation rate and for comparable sites Greenland NO3 − concentrations are a factor of 2 higher than in Antarctica. There is no evidence of solar modulation or supernova perturbation of Greenland NO3 − concentrations. The Byrd deep core is shown to have distinct seasonal variations in Cl− and SO4 2- that may be used for dating. In addition, the Byrd core contains volcanic signals similar to those found in Greenland. Recent Greenland snow contains about 4 times as much SO4 2- and 2 to 3 times as much NO3 − as is found in older ice due to modern fossil fuel combustion.

scholarly journals A 2700-year annual timescale and accumulation history for an ice core from Roosevelt Island, West Antarctica

2017 ◽  
Author(s):  
Mai Winstrup ◽  
Paul Vallelonga ◽  
Helle A. Kjær ◽  
Tyler J. Fudge ◽  
James E. Lee ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Early Period ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
Atmospheric Methane ◽  
Accumulation Rates ◽  
West Antarctica ◽  
Ross Ice Shelf ◽  
Accumulation History

Abstract. We present a 2700-year annually resolved timescale for the Roosevelt Island Climate Evolution (RICE) ice core, and reconstruct a past snow accumulation history for the coastal sector of the Ross Ice Shelf in West Antarctica. The timescale was constructed by identifying annual layers in multiple ice-core impurity records, employing both manual and automated counting approaches, and constitutes the top part of the Roosevelt Island Ice Core Chronology 2017 (RICE17). The maritime setting of Roosevelt Island results in high sulfate influx from sea salts and marine biogenic emissions, which prohibits a routine detection of volcanic eruptions in the ice-core records. This led to the use of non-traditional chronological techniques for validating the timescale: RICE was synchronized to the WAIS Divide ice core, on the WD2014 timescale, using volcanic attribution based on direct measurements of ice-core acidity, as well as records of globally-synchronous, centennial-scale variability in atmospheric methane concentrations. The RICE accumulation history suggests stable values of 0.25 m water equivalent (w.e.) per year until around 1260 CE. Uncertainties in the correction for ice flow thinning of annual layers with depth do not allow a firm conclusion about long-term trends in accumulation rates during this early period but from 1260 CE to the present, accumulation rate trends have been consistently negative. The decrease in accumulation rates has been increasingly rapid over the last centuries, with the decrease since 1950 CE being more than 7 times greater than the average over the last 300 years. The current accumulation rate of 0.22 ± 0.06 m w.e. yr−1 (average since 1950 CE, ±1σ) is 1.49 standard deviations (86th percentile) below the mean of 50-year average accumulation rates observed over the last 2700 years.

scholarly journals Sulphuric and Nitric Acid Concentrations and Spikes Along A 200 m Deep Ice Core at D 57 (Terre Adélie, Antarctica)

1985 ◽  
Vol 7 ◽  
pp. 70-75 ◽  
Author(s):  
Françoise Zanolini ◽  
Robert J. Delmas ◽  
Michel Legrand
Keyword(s):  
Nitric Acid ◽  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
The Other ◽  
Background Concentration ◽  
Volcanic Events ◽  
Mineral Acids ◽  
Terre Adélie

D 57 station in Terre Adélie lies between the coast and the central Antarctic plateau. A 200 m ice core was recovered in summer 1980–81 at this location and analyzed by an electroconductometric method to detect exceptional acid levels linked to fallout from major volcanic eruptions. Several signals were indeed found. The corresponding ice-core sections were then analyzed for mineral acids (H2SO4 and HNO3). We detected several large volcanic events, in particular two eruptions identified as Tarabora (1815) and Galunggung (1822). The background concentration of sulphate was found to be relatively low (about 0.5 μeq 1−1). On the other hand nitrate values were higher than at coastal or central Antarctic locations (except for the Sauth Pole). Two spikes were found in the nitrate profile at depths of 140 and 148 m. It is thought that they could be either linked to the 1604 and 1572 supernovae Kepler and Tycho or correspond to epochs of particularly high solar activities. With the aid of these sulphate and nitrate exceptional events, a dating of the D 57 ice core can now be proposed which corresponds to a mean snow accumulation rate of 22 cm of ice equivalent per year over the last four centuries.

scholarly journals 200 years of isotope and chemical records in a firn core from Hercules Névé, northern Victoria Land, Antarctica

1999 ◽  
Vol 29 ◽  
pp. 106-112 ◽  
Author(s):  
B. Stenni ◽  
R. Caprioli ◽  
L. Cimino ◽  
C. Cremisini ◽  
O. Flora ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
The Core ◽  
Victoria Land ◽  
Chemical Profiles ◽  
The 19Th Century ◽  
Calculated Average ◽  
Firn Core

AbstractA 42.2 m firn core was collected at the Hercules Névé plateau (100 km inland and 2960 m a.s.L), northern Victoria Land, during the 1994-95 Italian Antarctic Expedition. Chemical (Cl–, NO3–, SO42–’; δ18O δ18O δ18O; m-2a-1) and isotope (5180) analyses were performed to evaluate the snow-accumulation rate at this site. Tritium measurements were performed in the upper part of the core to narrow down the dating of the core.High nssSO42- concentrations seem to be related to some explosive volcanic eruptions, such as Tambora (AD 1815) and the preceding event called "Unknown" (AD 1809), Coseguina (AD 1835), Makjan (AD 1861), Krakatoa (AD 1883) and Tarawera (AD 1886).A comparison between the seasonal variations observed in the isotope and chemical profiles was carried out in order to reduce the dating uncertainty, using the tritium and the volcanic markers as time constraints. A deposition period of 222 years was determined.The 3 year smoothed «5180 profile shows more negative values from the bottom of the core (dated AD 1770) throughout the 19th century, suggesting "cooler" conditions, in agreement with other East Antarctic ice-core records! Subsequently, a general increase in δ180-values is observed.The calculated average snow-accumulation rates between the above-mentioned time markers are 111-129 kg m-2a-1.

scholarly journals Sulphuric and Nitric Acid Concentrations and Spikes Along A 200 m Deep Ice Core at D 57 (Terre Adélie, Antarctica)

1985 ◽  
Vol 7 ◽  
pp. 70-75 ◽  
Author(s):  
Françoise Zanolini ◽  
Robert J. Delmas ◽  
Michel Legrand
Keyword(s):  
Nitric Acid ◽  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Snow Accumulation ◽  
The Other ◽  
Background Concentration ◽  
Volcanic Events ◽  
Mineral Acids ◽  
Terre Adélie

D 57 station in Terre Adélie lies between the coast and the central Antarctic plateau. A 200 m ice core was recovered in summer 1980–81 at this location and analyzed by an electroconductometric method to detect exceptional acid levels linked to fallout from major volcanic eruptions. Several signals were indeed found. The corresponding ice-core sections were then analyzed for mineral acids (H2SO4 and HNO3). We detected several large volcanic events, in particular two eruptions identified as Tarabora (1815) and Galunggung (1822). The background concentration of sulphate was found to be relatively low (about 0.5 μeq 1−1). On the other hand nitrate values were higher than at coastal or central Antarctic locations (except for the Sauth Pole). Two spikes were found in the nitrate profile at depths of 140 and 148 m. It is thought that they could be either linked to the 1604 and 1572 supernovae Kepler and Tycho or correspond to epochs of particularly high solar activities. With the aid of these sulphate and nitrate exceptional events, a dating of the D 57 ice core can now be proposed which corresponds to a mean snow accumulation rate of 22 cm of ice equivalent per year over the last four centuries.

scholarly journals Reconstruction of recent climate change in Alaska from the Aurora Peak ice core, central Alaska

2015 ◽  
Vol 11 (2) ◽  
pp. 217-226 ◽  
Author(s):  
A. Tsushima ◽  
S. Matoba ◽  
T. Shiraiwa ◽  
S. Okamoto ◽  
H. Sasaki ◽  
...  
Keyword(s):  
Climate Change ◽  
Accumulation Rate ◽  
Ice Core ◽  
Chemical Species ◽  
Volcanic Eruptions ◽  
Gulf Of Alaska ◽  
Temporal Variations ◽  
Storm Activity ◽  
Alaska Range ◽  
Recent Climate

Abstract. A 180.17 m ice core was drilled at Aurora Peak in the central part of the Alaska Range, Alaska, in 2008 to allow reconstruction of centennial-scale climate change in the northern North Pacific. The 10 m depth temperature in the borehole was −2.2 °C, which corresponded to the annual mean air temperature at the drilling site. In this ice core, there were many melt–refreeze layers due to high temperature and/or strong insolation during summer seasons. We analyzed stable hydrogen isotopes (δD) and chemical species in the ice core. The ice core age was determined by annual counts of δD and seasonal cycles of Na+, and we used reference horizons of tritium peaks in 1963 and 1964, major volcanic eruptions of Mount Spurr in 1992 and Mount Katmai in 1912, and a large forest fire in 2004 as age controls. Here, we show that the chronology of the Aurora Peak ice core from 95.61 m to the top corresponds to the period from 1900 to the summer season of 2008, with a dating error of ± 3 years. We estimated that the mean accumulation rate from 1997 to 2007 (except for 2004) was 2.04 m w.eq. yr-1. Our results suggest that temporal variations in δD and annual accumulation rates are strongly related to shifts in the Pacific Decadal Oscillation index (PDOI). The remarkable increase in annual precipitation since the 1970s has likely been the result of enhanced storm activity associated with shifts in the PDOI during winter in the Gulf of Alaska.

A continuous 250-year record of volcanic activity from Princess Elizabeth Land, East Antarctica

2002 ◽  
Vol 14 (1) ◽  
pp. 55-60 ◽  
Author(s):  
M.J. Zhang ◽  
Z.Q. Li ◽  
C.D. Xiao ◽  
D.H. Qin ◽  
H.A. Yang ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Major Ions ◽  
Accumulation Rate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
East Antarctica ◽  
Mean Annual Temperature ◽  
High Definition ◽  
Concentration Data ◽  
High Accumulation

A 51.85 m ice core collected from site LGB65 (accumulation rate 127 kg m−2 a−1, mean annual temperature −33.1°C) in Princess Elizabeth Land, East Antarctica, during the 1996–97 Chinese First Antarctic Inland Expedition has been analysed for chemical composition and oxygen isotope ratio. Based on the high definition of seasonal variations of major ions, the ice core was dated with errors within ± 3 years. The continuous sulphate analysis of the ice core provides an annually resolved proxy history of southern hemisphere volcanism in the past 250 years. High nssSO42−, concentrations seem to be well correlated to some explosive volcanic eruptions, such as Tambora (AD 1815), Coseguina (AD 1835), Krakatoa (AD 1883) and Tarawera (AD 1886). In comparison with other volcanic records, it seems that nssSO42− concentration data provide a better proxy for detecting volcanic activity than nssSO42− fluxes in low and intermediate accumulation regions, however, in high accumulation regions, small and moderate events may be more identifiable using of nssSO42− flux data.

scholarly journals Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study

2021 ◽  
Author(s):  
Zhuang Jiang ◽  
Becky Alexander ◽  
Joel Savarino ◽  
Joseph Erbland ◽  
Lei Geng
Keyword(s):  
Seasonal Variations ◽  
Accumulation Rate ◽  
Ice Core ◽  
Snow Accumulation ◽  
Photic Zone ◽  
Seasonal Differences ◽  
Formation Pathway ◽  
Column Model ◽  
Annual Scale ◽  
Δ15n Variability

Abstract. Atmospheric information embedded in ice-core nitrate is disturbed by post-depositional processing. Here we used a layered snow photochemical column model to explicitly investigate the effects of post-depositional processing on snow nitrate and its isotopes (δ15N and Δ17O) at Summit, Greenland where post-depositional processing was thought to be minimal due to the high snow accumulation rate. We found significant redistribution of nitrate in the upper snowpack through photolysis and up to 21 % of nitrate was lost and/or redistributed after deposition. The model indicates post-depositional processing can reproduce much of the observed δ15N seasonality, while seasonal variations in δ15N of primary nitrate is needed to reconcile the timing of the lowest seasonal δ15N. In contrast, post-depositional processing can only induce less than 2.1 ‰ seasonal Δ17O change, much smaller than the observation (9 ‰) that is ultimately determined by seasonal differences in nitrate formation pathway. Despite significant redistribution of snow nitrate in the photic zone and the associated effects on δ15N seasonality, the net annual effect of post-depositional processing is relatively small, suggesting preservation of atmospheric signals at the annual scale under the present Summit conditions. But at longer timescales when large changes in snow accumulation rate occurs this post-depositional processing could become a major driver of the δ15N variability in ice core nitrate.

scholarly journals Persistent draining of the stratospheric 10Be reservoir after the Samalas volcanic eruption (1257 CE)

2020 ◽  
Author(s):  
Mélanie Baroni ◽  
Edouard Bard ◽  
Jean-Robert Petit ◽  
Sophie Viseur ◽  
Aster Team
Keyword(s):  
Ice Core ◽  
Volcanic Eruptions ◽  
Solar Modulation ◽  
Last Millennium ◽  
Climatic Impact ◽  
Air Masses ◽  
Sulphate Aerosols ◽  
Long Time ◽  
Modelling Studies ◽  
Volcanic Aerosols

<p>More than 2,000 analyses of beryllium‐10 (<sup>10</sup>Be) and sulphate concentrations were performed at a nominal subannual resolution on an ice core covering the last millennium as well as on shorter records from three sites in Antarctica (Dome C, South Pole, and Vostok) to better understand the increase in <sup>10</sup>Be deposition during stratospheric volcanic eruptions.</p><p>A significant increase in <sup>10</sup>Be concentration is observed in 14 of the 26 volcanic events studied. The slope and intercept of the linear regression between <sup>10</sup>Be and sulphate concentrations provide different and complementary information. Slope is an indicator of the efficiency of the draining of <sup>10</sup>Be atoms by volcanic aerosols depending on the amount of sulphur dioxide (SO<sub>2</sub>) released and on the altitude it reaches in the stratosphere. The intercept provides an appreciation of the <sup>10</sup>Be production in the stratospheric reservoir, ultimately depending on solar modulation (Baroni et al., 2019, JGR).</p><p>Among all the identified events, the Samalas event (1257 CE) stands out as the biggest eruption of the last millennium with the lowest positive slope. It released (158 ± 12) Tg of SO<sub>2</sub> up to an altitude of 43 km in the stratosphere (Lavigne et al., 2013, PNAS ; Vidal et al., 2016, Sci. Rep.). We hypothesize that the persistence of volcanic aerosols in the stratosphere after the Samalas eruption has drained the stratospheric <sup>10</sup>Be reservoir for a decade.</p><p>The persistence of Samalas sulphate aerosols might be due to the increase of SO<sub>2</sub> lifetime because of: (i) the exhaustion of the OH reservoir required for sulphate formation (e.g. (Bekki, 1995, GRL; Bekki et al., 1996, GRL; Savarino et al., 2003, JGR); and/or, (ii) the evaporation followed by photolysis of gaseous sulphuric acid back to SO<sub>2</sub> at altitudes higher than 30 km (Delaygue et al., 2015, Tellus; Rinsland et al., 1995, GRL). In addition, the lifetime of air masses increases to 5 years above 30 km altitude compared with 1 year for aerosols and air masses in the lower stratosphere (Delaygue et al., 2015, Tellus). When this high-altitude SO<sub>2</sub> finally returns below the 30 km limit, it could be oxidized back to sulphate and forms new sulphate aerosols. These processes could imply that the <sup>10</sup>Be reservoir is washed out over a long time period following the end of the eruption of Samalas.</p><p>This would run counter to modelling studies that predict the formation of large particle sizes and their rapid fall out due to the large amount of SO<sub>2</sub>, which would limit the climatic impact of Samalas-type eruptions (Pinto et al., 1989, JGR; Timmreck et al., 2010, 2009, GRL).</p>

scholarly journals A Glaciochemical Survey of the Summit Region, Greenland

1990 ◽  
Vol 14 ◽  
pp. 186-190 ◽  
Author(s):  
P.A. Mayewski ◽  
M.J. Spencer ◽  
M.S. Twickler ◽  
S. Whitlow
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Chemical Species ◽  
Deep Drilling ◽  
Major Cations ◽  
Signal Characteristics ◽  
Sampling Program ◽  
Major Anions ◽  
Major Chemical ◽  
Summit Region

Spatial representativeness and an understanding of controls on chemical species distribution are essential requirements of any significant ice core investigation. Snowpit studies provide an essential tool in this process. In preparation for the central Greenland deep drilling effort a series of snowpits was sampled in detail for oxygen isotopes, major anions, major cations, total acidity and radionuclides. The results of this sampling program are used to define: (1) the chemical composition of the snow in the region, (2) the input timing and spatial distribution of major chemical species, (3) the potential dependence of species concentration on accumulation rate, and (4) the signal characteristics identifiable in the region over the last few years.

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