Physical properties and alpha-/gamma-HCH concentrations in sea-ice and snow samples obtained during a CCGS Amundsen cruise, eastern Beaufort Sea

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Hauptverfasser: Pućko, Monika, Stern, Gary A, Macdonald, Robie W, Rosenberg, B, Barber, David G
Format: Dataset Open Access
Sprache:en
Veröffentlicht: PANGAEA 2011
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author Pućko, Monika
Stern, Gary A
Macdonald, Robie W
Rosenberg, B
Barber, David G
author_facet Pućko, Monika
Stern, Gary A
Macdonald, Robie W
Rosenberg, B
Barber, David G
collection Datos científicos de ciencias marinas y ambientales
contents The alpha- and gamma-hexachlorocyclohexanes (HCHs) are being scavenged from the atmosphere by falling snow, with the average total scavenging ratios (WT) of 3.8 x 10**4 and 9.6 x 10**3, respectively. After deposition, HCH snow concentrations can decrease by 40% because of snowpack ventilation and increase by 50% because of upward migration of brine from the ice. HCH vertical distribution in sufficiently cold winter sea ice, which maintains brine volume fractions <5%, reflects the ice growth history. Initially, the entrapment of brine (and HCHs) in ice depends on the rates of ice growth and desalination. However, after approximately the first week of ice formation, ice growth rate becomes dominant. Deviations of HCH concentrations from the values predicted by the ice bulk salinity (rate of brine entrapment) can be explained by spatial variability of HCHs in surface water. HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring when snow meltwater percolates into the ice, delivering HCHs to the upper ocean via desalination by flushing. Percolation can lead to an increase in alpha- and gamma-HCH in the sea ice by up to 2%-18% and 4%-32%, respectively.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_818648
institution PANGAEA
language en
publishDate 2011
publisher PANGAEA
record_format pangaea
spellingShingle Physical properties and alpha-/gamma-HCH concentrations in sea-ice and snow samples obtained during a CCGS Amundsen cruise, eastern Beaufort Sea
Pućko, Monika
Stern, Gary A
Macdonald, Robie W
Rosenberg, B
Barber, David G
International Polar Year (2007-2008); IPY
The alpha- and gamma-hexachlorocyclohexanes (HCHs) are being scavenged from the atmosphere by falling snow, with the average total scavenging ratios (WT) of 3.8 x 10**4 and 9.6 x 10**3, respectively. After deposition, HCH snow concentrations can decrease by 40% because of snowpack ventilation and increase by 50% because of upward migration of brine from the ice. HCH vertical distribution in sufficiently cold winter sea ice, which maintains brine volume fractions <5%, reflects the ice growth history. Initially, the entrapment of brine (and HCHs) in ice depends on the rates of ice growth and desalination. However, after approximately the first week of ice formation, ice growth rate becomes dominant. Deviations of HCH concentrations from the values predicted by the ice bulk salinity (rate of brine entrapment) can be explained by spatial variability of HCHs in surface water. HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring when snow meltwater percolates into the ice, delivering HCHs to the upper ocean via desalination by flushing. Percolation can lead to an increase in alpha- and gamma-HCH in the sea ice by up to 2%-18% and 4%-32%, respectively.
title Physical properties and alpha-/gamma-HCH concentrations in sea-ice and snow samples obtained during a CCGS Amundsen cruise, eastern Beaufort Sea
topic International Polar Year (2007-2008); IPY
url https://doi.org/10.1594/PANGAEA.818648