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| Titel |
Long term variability of cosmogenic and terrigenous radionuclides observed in the coastal Antarctica troposphere |
| VerfasserIn |
Christoph Elsässer, Dietmar Wagenbach, Ingeborg Levin, Rolf Weller, Anton Wallner |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040074
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| Zusammenfassung |
| We report on quasi-continuous radionuclides records obtained at the German Antarctic
Neumayer station since 1983 co-registered with ionic aerosol components and accompanied
by continuous observations of various atmospheric species (including radiocarbon and
radon). Emphasis will be on the cosmogenic 7Be and 10Be mainly produced in the lower
stratosphere as contrasted to 210Pb (a long lived decay product of the noble gas 222Rn which
is mainly emitted from continental surfaces). Different to the various chemical aerosol
components, the spatio-temporal source distributions are relatively well known for these
radionuclides (carried by the sub-micron aerosol fraction). Thus, particularly in combination,
they may constitute unique tracers for studying the meridional long range transport to
Antarctica as well as the stratosphere/troposphere air mass exchange. Time series analysis
aimed at establishing the climatology of these Antarctic records (as potentially deployed for
respective atmospheric transport model validation and retrospective ice core studies)
revealed:
regular seasonal cycles of the cosmogenic and terrigenous radionuclides, both,
broadly peaking in the austral summer half year. Particularly based on the
10Be/7Be ratio this finding allowed for simple quantification of the respective
seasonal change in the relative influence of stratospheric or high tropospheric air
masses seen at ground level.
decadal variation of the Be isotopes clearly related to their 11-years production
signal and, for 210Pb a periodicity of around 4 years potentially associated with
the Antarctic Oscillation index.
relatively weak long term trends of both radionuclide categories which are barely
significant over the observational period.
Implications of these formal findings are mainly discussed in view of the transport
properties of (short lived) atmospheric constituents to Antarctica, either from northward
continents or from the lower stratosphere. In backing up this attempt decadal scale runs of a
global 28-box model are presented as well as related Neumayer records (including among
others 222Rn and major chemical aerosol components). |
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