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| Titel |
Aerosol hygroscopicity parameter derived from the light scattering enhancement factor measurements in the North China Plain |
| VerfasserIn |
J. Chen, C. S. Zhao, N. Ma, P. Yan |
| 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 ; 14, no. 15 ; Nr. 14, no. 15 (2014-08-13), S.8105-8118 |
| Datensatznummer |
250118943
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| Publikation (Nr.) |
 copernicus.org/acp-14-8105-2014.pdf |
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| Zusammenfassung |
| The relative humidity (RH) dependence of aerosol light scattering is an
essential parameter for accurate estimation of the direct radiative forcing
induced by aerosol particles. Because of insufficient information on aerosol
hygroscopicity in climate models, a more detailed parameterization of
hygroscopic growth factors and resulting optical properties with respect to
location, time, sources, aerosol chemistry and meteorology are urgently
required. In this paper, a retrieval method to calculate the aerosol
hygroscopicity parameter, κ, is proposed based on the in situ
measured aerosol light scattering enhancement factor, namely f(RH), and
particle number size distribution (PNSD) obtained from the HaChi (Haze in
China) campaign. Measurements show that f(RH) increases sharply with
increasing RH, and that the time variance of f(RH) is much greater at higher
RH. A sensitivity analysis reveals that the f(RH) is more sensitive to the
aerosol hygroscopicity than PNSD. f(RH) for polluted cases is distinctly
higher than that for clean periods at a specific RH. The derived equivalent
κ, combined with the PNSD measurements, is applied in the prediction
of the cloud condensation nuclei (CCN) number concentration. The predicted CCN number concentration with
the derived equivalent κ agrees well with the measured ones,
especially at high supersaturations. The proposed calculation algorithm of
κ with the f(RH) measurements is demonstrated to be reasonable and
can be widely applied. |
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