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| Titel |
Chemical compositions of past soluble aerosols reconstructed from NEEM (Greenland) and Dome C (Antarctica) ice cores |
| VerfasserIn |
Ikumi Oyabu, Yoshinori Iizuka, Manabu Fukui, Hubertus Fischer, Simon Schüpbach, Gideon Gfeller, Robert Mulvaney, Margareta Hansson |
| 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 |
250101478
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| Publikation (Nr.) |
 EGU/EGU2015-629.pdf |
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| Zusammenfassung |
| Polar ice core preserve past atmospheric aerosols, which is a useful proxy for understanding
the interaction between climate changes and atmospheric aerosols. One useful technique for
reconstructing past soluble aerosols from ice core is the determination of dissolved ion
species. However, since salts and acids melt into ions, chemical compositions of
soluble aerosols in the ice cores have not been cleared. To clarify the temporal
variations in the chemical compositions of past soluble aerosols, this study investigated
chemical compositions of soluble particles preserved in the NEEM (Greenland) and
Dome C (Antarctica) ice cores using new method “ice-sublimation method”. The
ice-sublimation method can extract soluble salts particles as a solid state without
melting.
The ice core samples are selected from the sections from the last termination (the Last
Glacial Maximum (LGM) to Holocene) of Dome C (inland Antarctica) and NEEM ice cores.
Using ice-sublimation method, soluble salts particles were extracted. Chemical components
of extracted particles were analysed by scanning electron microscope and energy dispersive
spectroscopy, and micro-Raman spectroscopy.
The major components of soluble salts particles in the Dome C ice core are CaSO4,
Na2SO4 and NaCl. The CaSO4 and NaCl fractions were high in the first half of
the last termination, whereas the Na2SO4 fraction is high in the latter half of the
last termination. The major components of soluble salts particles in the NEEM
ice core are CaCO3, CaSO4, NaCl and Na2SO4. The fractions of CaCO3, CaSO4
and NaCl were high in LGM, whereas those of NaCl and Na2SO4 were high in
Holocene.
The changes in the salts compositions in Dome C ice core are mainly controlled by
concentration of terrestrial material (Ca2+). In the first half of the last termination, most of
the terrestrial material (CaCO3) reacted with H2SO4 but some of sea-salt (NaCl) was not
reacted with H2SO4 due to high Ca2+ concentration. As a result, the CaSO4 and NaCl
fractions were high in this period. In the latter half of the last termination, reaction of NaCl
with H2SO4 enhanced due to decreased in the Ca2+ concentration. As a result, Na2SO4
fraction increased. The changes in the salts compositions in NEEM ice core are also mainly
controlled by Ca2+ concentration. In the LGM, some of CaCO3 was reacted but
some of CaCO3 and most of NaCl were not reacted with H2SO4 due to too high
Ca2+ concentration. As a result, CaCO3, CaSO4 and NaCl fractions were high
in LGM. In the Holocene, NaCl sulfatization increased due to reduction of Ca2+
concentration. However, some of NaCl was not sulfatized due to different seasonality of
NaCl and H2SO4, and increased in the NH4+ inputs originate from vegetation. |
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