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| Titel |
Past atmospheric krypton and xenon over the last 24,000 years from trapped air in polar ice cores: A potential constraint on mean ocean temperature |
| VerfasserIn |
Kenji Kawamura, Jeffrey P. Severinghaus, Daniel Baggenstos, Anaïs Orsi, Christo Buizert, Shuji Aoki, Takakiyo Nakazawa |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105936
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| Publikation (Nr.) |
 EGU/EGU2015-8951.pdf |
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| Zusammenfassung |
| Prior work has shown that atmospheric concentrations of Kr and Xe respond mainly to mean
ocean temperature variations, due to their strongly temperature-dependent solubility in liquid
water and due to the fact that no significant sources or sinks exist in the ocean-atmosphere
system (Headly and Severinghaus, 2007 JGR; Ritz et al., 2011 QSR). Because roughly 80%
of the ocean’s volume is colder than 4Ë C, and cold water holds more gas than warm
water, the atmospheric noble gases Kr and Xe mainly record changes in deep ocean
temperature. Records from the WAIS Divide, GISP2 and Dome Fuji ice cores show a large
increase in the Kr/N2 and Xe/N2 over the time interval 19 ka to 15 ka, equivalent to
~1.5 Ë C deep ocean warming (from the WAIS data and a box model). This time
interval is contemporaneous with Heinrich Stadial 1, a time of strong retreat of
southern hemisphere mountain glaciers, rapid warming of southern mid-latitude
surface waters, and weak northern hemisphere monsoons, all consistent with a
south-shifted ITCZ and weak Atlantic Meridional Overturning Circulation (the “bipolar
see-saw” in its warm-south mode). These new data are consistent with the idea that
the initial rise in CO2 at the last Termination was caused by a strong increase in
the rate at which the deep ocean is exposed to the atmosphere around Antarctica
(known as “ventilation”) and the concomitant release of CO2 to the atmosphere. The
WAIS Divide data also suggest a slow-down of ocean warming between 15 ka and
13 ka, and then the second strong warming by about one degree until ~11.5 ka,
roughly coincident with Antarctic Cold Reversal and Younger Dryas, respectively. |
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