Ratios of Mg2+/Na+ in snowpack and an ice core at Austfonna ice cap, Svalbard, as an indicator of seasonal melting

AbstractSnowpack and ice-core samples were collected from the dome of Austfonna ice cap, Svalbard, in the spring of both 1998 and 1999. The samples were analyzed for anions, cations, pH, liquid electrical conductivity and oxygen isotopes. Concentrations of chemical components in snowpack with a history of melting were much lower than those in unmelted snowpack. There was a clear difference between Mg2+/Na+ ratios previously in melted snowpack (0.03 ± 0.02) and in unmelted snowpack (0.11 ± 0.02). We propose that the Mg2+/Na+ ratio can be used as an indicator of whether or not firn or bubbly ice in the Austfonna ice core has experienced melt percolation. The Mg2+/Na+ ratio indicates that firn or bubbly ice prior to AD 1920 was much less affected by melt percolation than firn or bubbly ice formed after 1920.

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Climate Change: What’s the Big Deal?

Paying for Pollution ◽

10.1093/oso/9780190694197.003.0002 ◽

2019 ◽

pp. 7-22

Author(s):

Gilbert E. Metcalf

Keyword(s):

Climate Change ◽

Greenhouse Gases ◽

Sea Level Rise ◽

Sea Level ◽

Ice Core ◽

Core Samples ◽

History Of ◽

The Cost ◽

Climate Damages

Droughts, floods, soaring temperatures, sea-level rise, and melting ice are just some of the damages brought about by climate change. Chapter 1 details the cost of our failure to cut our emissions, from crop-destroying droughts to devastating floods. It also documents the inexorable build-up of greenhouse gases in the atmosphere as demonstrated by the Keeling curve and observations from Antarctic ice core samples. The chapter then provides a brief history of the science linking the build-up of atmospheric greenhouse gases and climate damages.

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Glaciochemical reconnaissance of a new ice core from Severnaya Zemlya, Eurasian Arctic

Journal of Glaciology ◽

10.3189/172756505781829629 ◽

2005 ◽

Vol 51 (172) ◽

pp. 64-74 ◽

Cited By ~ 21

Author(s):

Karin Weiler ◽

Hubertus Fischer ◽

Diedrich Fritzsche ◽

Urs Ruth ◽

Frank Wilhelms ◽

...

Keyword(s):

Electrical Conductivity ◽

Ice Core ◽

Arctic Basin ◽

Anthropogenic Pollution ◽

The Arctic ◽

Ice Cap ◽

Siberian Arctic ◽

Nitrate Concentrations ◽

Severnaya Zemlya ◽

Combustion Processes

AbstractA deep ice core has been drilled on Akademii Nauk ice cap, Severnaya Zemlya, Eurasian Arctic. High-resolution chemical analysis has been carried out for the upper 53 m of this ice core to study its potential as an atmospheric aerosol archive, despite strong meltwater percolation. These records show that a seasonal atmospheric signal cannot be deduced. However, strong year-to-year variations have allowed the core to be dated, and a mean annual net mass balance of 0.46 m w.e. a-1 was deduced. The chemical signature of an extraordinarily high peak in electrical conductivity at 26 m depth pointed clearly to the eruption of Bezymianny, Kamchatka, in 1956. However, in general, peaks in the electrical conductivity are not necessarily related to deposition of volcanogenic sulphur aerosol. In contrast, maximum sulphate and nitrate concentrations in the ice could be related to maximum SO2 and NOx anthropogenic emissions in the 1970s, probably caused by the nickel- and copper-producing industries in Norilsk and on the Kola peninsula or by industrial combustion processes occurring in the Siberian Arctic. In addition, during recent decades sulphate and nitrate concentrations declined by 80% and 60%, respectively, reflecting a decrease in anthropogenic pollution of the Arctic basin.

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A comparison of radio-echo sounding data and electrical conductivity of the GRIP ice core

Journal of Glaciology ◽

10.3189/172756500781833070 ◽

2000 ◽

Vol 46 (154) ◽

pp. 369-374 ◽

Cited By ~ 50

Author(s):

Ludwig Hempel ◽

Franz Thyssen ◽

Niels Gundestrup ◽

Henrik B. Clausen ◽

Heinz Miller

Keyword(s):

Electrical Conductivity ◽

Electromagnetic Wave ◽

Wave Velocity ◽

Ice Core ◽

Volcanic Eruptions ◽

Ice Cap ◽

Radio Echo Sounding ◽

Arctic Ice ◽

Core Project ◽

Echo Sounding

AbstractThe depth of reflecting layers in Arctic ice sheets has been determined by electromagnetic echo sounding, using a varying distance between transmitter and receiver to determine the radar wave velocity. The depth of the radar reflecting layers is compared with a profile of electrical conductivity measurements (ECMs) from the Greenland Ice Core Project (GRIP) ice core, in order to determine the velocity of the radar waves in the ice cap. By using several reflecting layers, it is possible to isolate the firn correction of the wave velocity and to estimate the accuracy of the calculated electromagnetic wave velocity. The measured firn correction is compared with the correction calculated from the density profile, and a comparison between the depth profiles of ECM and radar based on the corrected electromagnetic wave velocity is presented. This profile shows that acid layers, which originate from major volcanic eruptions, show up as reflecting radar horizons.

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10,000 years of melt history of the 2015 Renland ice core, EastGreenland

10.5194/tc-2018-280 ◽

2019 ◽

Cited By ~ 2

Author(s):

Tetsuro Taranczewski ◽

Johannes Freitag ◽

Olaf Eisen ◽

Bo Vinther ◽

Sonja Wahl ◽

...

Keyword(s):

Ice Core ◽

Greenland Ice Sheet ◽

Ice Age ◽

Strong Increase ◽

Past Century ◽

Additional Information ◽

The Past ◽

Ice Cap ◽

History Of ◽

Paleoclimate Records

Abstract. An ice core drilled in 2015 on the Renland ice cap at the eastern margin of Greenland has been inspected with regard to its melt content. The thickness of a melt layer reflects the temperature level at the time of melt generation. Hence the melt layers are an indicator of past regional summer temperatures in East Greenland, a region where paleoclimate records are sparse. Melt layers have been identified almost along the whole core, resulting in a melt record reaching back 10,000 years. By gathering additional information about melt rates as well as high-resolution densities in two shallow cores, we developed an approach to correct the annual melt content for the ice volume that gets lost by the thinning process. The result is a melt record with decadal- to centennial- scale resolution for the last two millennia, and the most accurate Holocene climate record for Eastern Greenland so far. The observed changes of annual melt rates show a warm early Holocene, with melt rates higher than in the recent past century, and minimum melting during the Little Ice Age. Current melt rates show a strong increase for the early 20th century as well as for the time since the end of the past century, with the recent 2012 extreme melting of the Greenland Ice Sheet being the strongest melt event in the past 500 years.

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Pollen Analysis of Ice Core Samples from the Devon Island Ice Cap

10.4095/104620 ◽

1975 ◽

Cited By ~ 4

Author(s):

S Lichti-Federovich

Keyword(s):

Pollen Analysis ◽

Ice Core ◽

Devon Island ◽

Core Samples ◽

Ice Cap

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Post-coring entrapment of modern air in polar ice cores collected near the firn-ice transition: evidence from CFC-12 measurements in Antarctic firn air and shallow ice cores

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-1631-2010 ◽

2010 ◽

Vol 10 (1) ◽

pp. 1631-1657 ◽

Cited By ~ 1

Author(s):

M. Aydin ◽

S. A. Montzka ◽

M. O. Battle ◽

M. B. Williams ◽

W. De Bruyn ◽

...

Keyword(s):

Ice Core ◽

Ice Cores ◽

Trace Gas ◽

Gas Composition ◽

Physical Processes ◽

Polar Ice ◽

Air Samples ◽

Mixing Ratios ◽

Core Samples ◽

History Of

Abstract. In this study, we report the first measurements of CFC-12 (CCl2F2) in air extracted from shallow ice cores along with firn air CFC-12 measurements from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for presence of modern air entrapped in shallow ice core samples. We propose that this is due to closure of open pores after drilling, entrapping modern air and resulting in elevated CFC-12 mixing ratios. Our measurements reveal the presence of open porosity below the depth at which firn air samples can be collected and demonstrate how the composition of bubble air in shallow ice cores can be altered during the post-drilling period through purely physical processes. These results have implications for investigations involving trace gas composition of bubbles in shallow ice cores.

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A 275 year ice-core record from Akademii Nauk ice cap, Severnaya Zemlya, Russian Arctic

Annals of Glaciology ◽

10.3189/172756405781812862 ◽

2005 ◽

Vol 42 ◽

pp. 361-366 ◽

Cited By ~ 26

Author(s):

Diedrich Fritzsche ◽

Rainer Schütt ◽

Hanno Meyer ◽

Heinz Miller ◽

Frank Wilhelms ◽

...

Keyword(s):

Electrical Conductivity ◽

Ice Core ◽

Russian Arctic ◽

Stable Water Isotopes ◽

Additional Time ◽

High Resolution Data ◽

Ice Cap ◽

Core Section ◽

Ice Core Record ◽

Severnaya Zemlya

AbstractBetween 1999 and 2001, a 724 m long ice core was drilled on Akademii Nauk, the largest glacier on Severnaya Zemlya, Russian Arctic. The drilling site is located near the summit. The core is characterized by high melt-layer content. The melt layers are caused by melting and even by rain during the summer. We present high-resolution data of density, electrical conductivity (dielectrical profiling), stable water isotopes and melt-layer content for the upper 136m (120 m w.e.) of the ice core. The dating by isotopic cycles and electrical conductivity peak identification suggests that this core section covers approximately the past 275 years. Singularities of volcanogenic and anthropogenic origin provide well-defined additional time markers. Long-term temperatures inferred from 12 year running mean averages of δ18O reach their lowest level in the entire record around 1790. Thereafter the δ18O values indicate a continuously increasing mean temperature on the Akademii Nauk ice cap until 1935, interrupted only by minor cooling episodes. The 20th century is found to be the warmest period in this record.

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Post-coring entrapment of modern air in some shallow ice cores collected near the firn-ice transition: evidence from CFC-12 measurements in Antarctic firn air and ice cores

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-5135-2010 ◽

2010 ◽

Vol 10 (11) ◽

pp. 5135-5144 ◽

Cited By ~ 17

Author(s):

M. Aydin ◽

S. A. Montzka ◽

M. O. Battle ◽

M. B. Williams ◽

W. J. De Bruyn ◽

...

Keyword(s):

Ice Core ◽

Ice Cores ◽

Trace Gas ◽

Gas Composition ◽

Accumulation Rates ◽

Physical Processes ◽

Air Samples ◽

Mixing Ratios ◽

Core Samples ◽

History Of

Abstract. In this study, we report measurements of CFC-12 (CCl2F2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the ice core and firn air data provide evidence for the presence of modern air entrapped in the shallow ice core samples that likely contained open pores at the time of collection. We propose that this is due to closure of the open pores after drilling, entrapping modern air and resulting in elevated CFC-12 mixing ratios. Our results reveal that open porosity can exist below the maximum depth at which firn air samples can be collected, particularly at sites with lower accumulation rates. CFC-12 measurements demonstrate that post-drilling closure of open pores can lead to a change in the composition of bubble air in shallow ice cores through purely physical processes. The results have implications for investigations involving trace gas composition of bubbles in shallow ice cores collected near the firn-ice transition.

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