scholarly journals Trace Elements in Antarctic Air and Snowfall

1985 ◽  
Vol 7 ◽  
pp. 12-19 ◽  
Author(s):  
A.L. Dick ◽  
D.A. Peel
Keyword(s):  
Trace Elements ◽  
Time Series Data ◽  
Ice Cores ◽  
Enrichment Factors ◽  
Atmospheric Composition ◽  
Series Data ◽  
Contamination Control ◽  
Polar Ice Sheets ◽  
Firm Basis ◽  
The Antarctic

Measurements of trace elements in snow and ice are frequently used to describe past atmospheric composition although there is no firm basis for assuming a direct connection. Trace-element concentrations have been measured on samples of aerosol and freshly fallen snow collected simultaneously from two sites in the Antarctic Peninsula during summer. Following improvements in contamination control, the reported concentrations and crustal enrichment factors of Cd, Cu, Pb and Zn in the aerosol are lower than any values previously reported from Antarctica. Even tighter controls will be required in the future.For a crustal element (A1) and for the marine cations (Na, Ca and K) a consistent ratio (0.48±0.31) for the concentration in air (pg m−3)/concentration in snow (pg g−1) is obtained for simultaneously collected samples. This supports a simple model of aerosol scavenging proposed by Junge which considers aerosol removal over polar ice sheets to be dominated by in-cloud processes. Averaged data for Cd, Cu, Pb and Zn from samples collected at different times appear to behave similarly. These findings suggest that there is no preferential scavenging by snowfall of either crustal or heavy metal components in contemporary aerosol. If proved more general in Antarctica this may help to simplify the interpretation of time series data from ice cores.

scholarly journals Trace Elements in Antarctic Air and Snowfall

1985 ◽  
Vol 7 ◽  
pp. 12-19 ◽  
Author(s):  
A.L. Dick ◽  
D.A. Peel
Keyword(s):  
Trace Elements ◽  
Time Series Data ◽  
Ice Cores ◽  
Enrichment Factors ◽  
Atmospheric Composition ◽  
Series Data ◽  
Contamination Control ◽  
Polar Ice Sheets ◽  
Firm Basis ◽  
The Antarctic

Measurements of trace elements in snow and ice are frequently used to describe past atmospheric composition although there is no firm basis for assuming a direct connection. Trace-element concentrations have been measured on samples of aerosol and freshly fallen snow collected simultaneously from two sites in the Antarctic Peninsula during summer. Following improvements in contamination control, the reported concentrations and crustal enrichment factors of Cd, Cu, Pb and Zn in the aerosol are lower than any values previously reported from Antarctica. Even tighter controls will be required in the future. For a crustal element (A1) and for the marine cations (Na, Ca and K) a consistent ratio (0.48±0.31) for the concentration in air (pg m−3)/concentration in snow (pg g−1) is obtained for simultaneously collected samples. This supports a simple model of aerosol scavenging proposed by Junge which considers aerosol removal over polar ice sheets to be dominated by in-cloud processes. Averaged data for Cd, Cu, Pb and Zn from samples collected at different times appear to behave similarly. These findings suggest that there is no preferential scavenging by snowfall of either crustal or heavy metal components in contemporary aerosol. If proved more general in Antarctica this may help to simplify the interpretation of time series data from ice cores.

Trace-Acid Ion Content of Shallow Snow and Ice Cores from Mountain Sites in Western Canada

1988 ◽  
Vol 10 ◽  
pp. 57-62 ◽  
Author(s):  
G. Holdsworth ◽  
H.R. Krouse ◽  
E. Peake
Keyword(s):  
British Columbia ◽  
Time Series ◽  
Forest Fires ◽  
Time Series Data ◽  
Accumulation Rate ◽  
Ice Cores ◽  
Historical Record ◽  
Yukon Territory ◽  
Series Data ◽  
Snow And Ice

An historical record of the deposition of common acids is contained in snow and ice cores taken from suitable sites in the accumulation zone of certain glaciers. Spatial and time-series data sets for trace-mineral acids have been obtained from snow-pit samples and ice cores from a number of mountain sites in Alberta, British Columbia, and the Northwest and Yukon Territories. In Alberta, it is possible to use temperate firn sites above 3460 m, although elution occurs during certain summers as indicated by isotopic and ionic data. This would also apply to sites of a similar latitude (52°±2°N) in British Columbia. In the Yukon Territory (≥60.5°N) reliable time series for the acid anions may be obtained from sites at altitudes above 3000 m. Elution provides a natural control for demonstrating that field sampling and subsequent analytical procedures do not introduce significant contamination. The Yukon data are compared with the net annual accumulation rate and with altitude. Recent data from the 5340 m Mt Logan site do not indicate any significant increase in natural background levels of snow acidity. Lightning, which is responsible for numerous forest fires in all provinces, is a possible natural source of nitric acid. Spring-summer peaks in nitrate concentration usually occur. In addition, forest-fire smoke may be a significant contributor to the mountain snow-pack chemistry in some years and must be considered when interpreting the Mt Logan core data. One Yukon profile seems to contain the signature from the 1986 Augustine volcanic eruption.

scholarly journals Observed and simulated time evolution of HCl, ClONO<sub>2</sub>, and HF total column abundances

2011 ◽  
Vol 11 (12) ◽  
pp. 32085-32160 ◽  
Author(s):  
R. Kohlhepp ◽  
R. Ruhnke ◽  
M. P. Chipperfield ◽  
M. De Mazière ◽  
J. Notholt ◽  
...  
Keyword(s):  
Time Series ◽  
Northern Hemisphere ◽  
Time Series Data ◽  
Montreal Protocol ◽  
Irregular Sampling ◽  
Atmospheric Composition ◽  
Series Data ◽  
Anthropogenic Source ◽  
Time Range ◽  
Total Column

Abstract. Time series of total column abundances of hydrogen chloride (HCl), chlorine nitrate (ClONO2), and hydrogen fluoride (HF) were determined from ground-based Fourier transform infrared (FTIR) spectra recorded at 17 sites belonging to the Network for the Detection of Atmospheric Composition Change (NDACC) and located between 80.05° N and 77.82° S. These measurements are compared with calculations from five different models: the two-dimensional Bremen model, the two chemistry-transport models KASIMA and SLIMCAT, and the two chemistry-climate models EMAC and SOCOL. The overall agreement between the measurements and models for the total column abundances and the seasonal cycles is good. Trends of HCl, ClONO2, and HF are calculated from both measurement and model time series data, with a focus on the time range 2000–2009. Their precision is estimated with the bootstrap resampling method. The sensitivity of the trend results with respect to the fitting function, the time of year chosen and time series length is investigated, as well as a bias due to the irregular sampling of the measurements. For the two chlorine species, a decrease is expected during this period because the emission of their prominent anthropogenic source gases (solvents, chlorofluorocarbons (CFCs)) was restricted by the Montreal Protocol 1987 and its amendments and adjustments. As most of the restricted source gases also contain fluorine, the HF total column abundance was also influenced by the above-mentioned regulations in the time period considered. The measurements and model results investigated here agree qualitatively on a decrease of the chlorine species by around −1 % yr−1. The models simulate an increase of HF of around +1 % yr−1. This also agrees well with most of the measurements, but some of the FTIR series in the Northern Hemisphere show a stabilisation or even a decrease in the last few years. In general, for all three gases, the measured trends vary more strongly with latitude and hemisphere than the modelled trends. Relative to the FTIR measurements, the models tend to underestimate the decreasing chlorine trends and to overestimate the fluorine increase in the Northern Hemisphere. At most sites, the models simulate a stronger decrease of ClONO2 than of HCl. In the FTIR measurements, this difference between the trends of HCl and ClONO2 depends strongly on latitude, especially in the Northern Hemisphere.

scholarly journals The Influence On Atmospheric Composition of Volcanic Eruptions as Derived From Ice-Core Analysis

1985 ◽  
Vol 7 ◽  
pp. 125-129 ◽  
Author(s):  
C.U. Hammer
Keyword(s):  
Ice Core ◽  
Ice Sheets ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Atmospheric Composition ◽  
Core Analysis ◽  
Polar Ice ◽  
Ice Caps ◽  
The Past ◽  
Polar Ice Sheets

Polar ice cores offer datable past snow deposits in the form of annual ice layers, which reflect the past atmospheric composition. Trace substances in the cores are related to the past mid-tropospheric impurity load, this being due to the vast extent of the polar ice sheets (or ice caps), their surface elevations and remoteness from most aerosol sources. Volcanic eruptions add to the rather low background impurity load via their eruptive products. This paper concentrates on the widespread influence on atmospheric impurity loads caused by the acid gas products from volcanic eruptions. In particular the following subjects are discussed: acid volcanic signals in ice cores, latitude of eruptions as derived by ice-core analysis, inter-hemispheric dating of the two polar ice sheets by equatorial eruptions, volcanic deposits in ice cores during the last glacial period and climatic implications.

scholarly journals The Influence On Atmospheric Composition of Volcanic Eruptions as Derived From Ice-Core Analysis

1985 ◽  
Vol 7 ◽  
pp. 125-129 ◽  
Author(s):  
C.U. Hammer
Keyword(s):  
Ice Core ◽  
Ice Sheets ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Atmospheric Composition ◽  
Core Analysis ◽  
Polar Ice ◽  
Ice Caps ◽  
The Past ◽  
Polar Ice Sheets

Polar ice cores offer datable past snow deposits in the form of annual ice layers, which reflect the past atmospheric composition. Trace substances in the cores are related to the past mid-tropospheric impurity load, this being due to the vast extent of the polar ice sheets (or ice caps), their surface elevations and remoteness from most aerosol sources. Volcanic eruptions add to the rather low background impurity load via their eruptive products. This paper concentrates on the widespread influence on atmospheric impurity loads caused by the acid gas products from volcanic eruptions. In particular the following subjects are discussed: acid volcanic signals in ice cores, latitude of eruptions as derived by ice-core analysis, inter-hemispheric dating of the two polar ice sheets by equatorial eruptions, volcanic deposits in ice cores during the last glacial period and climatic implications.

scholarly journals On the Origin of Stratified Debris in Ice Cores from the Bottom of the Antarctic Ice Sheet

1979 ◽  
Vol 23 (89) ◽  
pp. 185-192 ◽  
Author(s):  
A. J. Gow ◽  
S. Epstein ◽  
W. Sheehy
Keyword(s):  
Ice Sheet ◽  
Ice Cores ◽  
Gas Content ◽  
Antarctic Ice Sheet ◽  
Glacial Ice ◽  
Major Mechanism ◽  
Basal Ice ◽  
Polar Ice Sheets ◽  
Rock Interface ◽  
The Antarctic

Abstract Cores from the bottom 4.83 m of the Antarctic ice sheet at Byrd Station contain abundant stratified debris ranging from silt-sized particles to cobbles. The nature and disposition of the debris, together with measurements of the physical properties of the inclosing ice, indicate that this zone of dirt-laden ice originated by “freezing-in” at the base of the ice sheet. The transition from air-rich glacial ice to ice practically devoid of air coincided precisely with the first appearance of debris in the ice at 4.83 m above the bed. Stable-isotope studies made in conjunction with gas-content measurements also confirm the idea of incorporation of basal debris by adfreezing of melt water at the ice―rock interface. It is suggested that the absence of air from basal ice may well constitute the most diagnostic test for discriminating between debris incorporated in a melt―refreeze process and debris entrapped by purely mechanical means, e.g. shearing. We conclude from our observations on bottom cores from Byrd Station that “freezing-in” of basal debris is the major mechanism by which sediment is incorporated into polar ice sheets.

scholarly journals Trace-Acid Ion Content of Shallow Snow and Ice Cores from Mountain Sites in Western Canada

1988 ◽  
Vol 10 ◽  
pp. 57-62 ◽  
Author(s):  
G. Holdsworth ◽  
H.R. Krouse ◽  
E. Peake
Keyword(s):  
British Columbia ◽  
Time Series ◽  
Forest Fires ◽  
Time Series Data ◽  
Accumulation Rate ◽  
Ice Cores ◽  
Historical Record ◽  
Yukon Territory ◽  
Series Data ◽  
Snow And Ice

An historical record of the deposition of common acids is contained in snow and ice cores taken from suitable sites in the accumulation zone of certain glaciers. Spatial and time-series data sets for trace-mineral acids have been obtained from snow-pit samples and ice cores from a number of mountain sites in Alberta, British Columbia, and the Northwest and Yukon Territories. In Alberta, it is possible to use temperate firn sites above 3460 m, although elution occurs during certain summers as indicated by isotopic and ionic data. This would also apply to sites of a similar latitude (52°±2°N) in British Columbia. In the Yukon Territory (≥60.5°N) reliable time series for the acid anions may be obtained from sites at altitudes above 3000 m. Elution provides a natural control for demonstrating that field sampling and subsequent analytical procedures do not introduce significant contamination. The Yukon data are compared with the net annual accumulation rate and with altitude. Recent data from the 5340 m Mt Logan site do not indicate any significant increase in natural background levels of snow acidity. Lightning, which is responsible for numerous forest fires in all provinces, is a possible natural source of nitric acid. Spring-summer peaks in nitrate concentration usually occur. In addition, forest-fire smoke may be a significant contributor to the mountain snow-pack chemistry in some years and must be considered when interpreting the Mt Logan core data. One Yukon profile seems to contain the signature from the 1986 Augustine volcanic eruption.

scholarly journals On the Origin of Stratified Debris in Ice Cores from the Bottom of the Antarctic Ice Sheet

1979 ◽  
Vol 23 (89) ◽  
pp. 185-192 ◽  
Author(s):  
A. J. Gow ◽  
S. Epstein ◽  
W. Sheehy
Keyword(s):  
Ice Sheet ◽  
Ice Cores ◽  
Gas Content ◽  
Antarctic Ice Sheet ◽  
Glacial Ice ◽  
Major Mechanism ◽  
Basal Ice ◽  
Polar Ice Sheets ◽  
Rock Interface ◽  
The Antarctic

AbstractCores from the bottom 4.83 m of the Antarctic ice sheet at Byrd Station contain abundant stratified debris ranging from silt-sized particles to cobbles. The nature and disposition of the debris, together with measurements of the physical properties of the inclosing ice, indicate that this zone of dirt-laden ice originated by “freezing-in” at the base of the ice sheet. The transition from air-rich glacial ice to ice practically devoid of air coincided precisely with the first appearance of debris in the ice at 4.83 m above the bed. Stable-isotope studies made in conjunction with gas-content measurements also confirm the idea of incorporation of basal debris by adfreezing of melt water at the ice―rock interface. It is suggested that the absence of air from basal ice may well constitute the most diagnostic test for discriminating between debris incorporated in a melt―refreeze process and debris entrapped by purely mechanical means, e.g. shearing. We conclude from our observations on bottom cores from Byrd Station that “freezing-in” of basal debris is the major mechanism by which sediment is incorporated into polar ice sheets.

scholarly journals Satellite-derived dry-snow line as an indicator of the local climate on the Antarctic Peninsula

2021 ◽  
pp. 1-11
Author(s):  
Chunxia Zhou ◽  
Yong Liu ◽  
Lei Zheng
Keyword(s):  
Antarctic Peninsula ◽  
Climate Models ◽  
Time Series Data ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Climatic Variables ◽  
Series Data ◽  
Local Climate ◽  
Snow Line ◽  
The Antarctic

Abstract Recent regional cooling has impacted the natural systems of the Antarctic Peninsula (AP); however, little is known concerning the changes in the high parts of the glacial systems. Dry-snow line (DSL), situated in the high parts of glaciers, is the uppermost limit of frequent or occasional surface melt. We analyse dry-snow line altitude (DSLA) changes on the AP during 2004–2020 using C-band synthetic aperture radar time series data. We demonstrate that the DSLA in the eastern part of the AP is usually higher than that of the western part. Moreover, using simulated climatic variables from regional climate models, the lowering in altitude of DSL of glaciers in most areas is identified as a response to a decrease in snowmelt and an increase in precipitation. Furthermore, correlation analyses between simulated climatic variables and the DSLA are conducted. These results present the sensitive response of variations in DSLA to meteorological conditions, and the capability of DSLA being a proxy of polar local climate in high-altitude areas with no in situ meteorological observations.

Graphical Exploratory Data Analysis for Categorical Longitudinal and Time Series Data

2013 ◽  
Author(s):  
Stephen J. Tueller ◽  
Richard A. Van Dorn ◽  
Georgiy Bobashev ◽  
Barry Eggleston
Keyword(s):  
Time Series ◽  
Data Analysis ◽  
Exploratory Data Analysis ◽  
Time Series Data ◽  
Series Data ◽  
Exploratory Data
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