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| Titel |
Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties |
| VerfasserIn |
J. Zábori, R. Krejci, J. Ström, P. Vaattovaara, A. M. L. Ekman, M. E. Salter, E. M. Mårtensson, E. D. Nilsson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 9 ; Nr. 13, no. 9 (2013-05-08), S.4783-4799 |
| Datensatznummer |
250018640
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| Publikation (Nr.) |
 copernicus.org/acp-13-4783-2013.pdf |
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| Zusammenfassung |
| Primary marine aerosols (PMAs) are an important source of cloud
condensation nuclei, and one of the key elements of the remote marine
radiative budget. Changes occurring in the rapidly warming Arctic,
most importantly the decreasing sea ice extent, will alter PMA
production and hence the Arctic climate through a set of feedback
processes. In light of this, laboratory experiments with Arctic Ocean
water during both Arctic winter and summer were conducted and focused
on PMA emissions as a function of season and water properties. Total
particle number concentrations and particle number size distributions
were used to characterize the PMA population. A comprehensive data set
from the Arctic summer and winter showed a decrease in PMA
concentrations for the covered water temperature (Tw)
range between −1°C and
15°C. A sharp decrease in PMA emissions for
a Tw increase from −1°C to
4°C was followed by a lower rate of change in PMA
emissions for Tw up to about 6°C. Near
constant number concentrations for water temperatures between
6°C to 10°C and higher were
recorded. Even though the total particle number concentration changes
for overlapping Tw ranges were consistent between the
summer and winter measurements, the distribution of particle number
concentrations among the different sizes varied between the
seasons. Median particle number concentrations for a dry diameter (Dp<
0.125μm measured during winter conditions were similar
(deviation of up to 3%), or lower (up to 70%) than the ones
measured during summer conditions (for the same water temperature
range). For Dp > 0.125μm, the particle
number concentrations during winter were mostly higher than in summer
(up to 50%). The normalized particle number size distribution as
a function of water temperature was examined for both winter and
summer measurements. An increase in Tw from
−1°C to 10°C during winter
measurements showed a decrease in the peak of relative particle number
concentration at about a Dp of 0.180μm, while
an increase was observed for particles with Dp >
1μm. Summer measurements exhibited a relative shift to
smaller particle sizes for an increase of Tw in the
range 7–11°C. The differences in the shape of the
number size distributions between winter and summer may be caused by
different production of organic material in water, different local
processes modifying the water masses within the fjord (for example sea ice
production in winter and increased glacial meltwater inflow during
summer) and different origin of the dominant sea water mass. Further
research is needed regarding the contribution of these factors to the
PMA production. |
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