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| Titel |
The impact of aerosol hygroscopic growth on the single-scattering albedo and its application on the NO2 photolysis rate coefficient |
| VerfasserIn |
J. C. Tao, C. S. Zhao, N. Ma, P. F. Liu |
| 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. 22 ; Nr. 14, no. 22 (2014-11-17), S.12055-12067 |
| Datensatznummer |
250119164
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| Publikation (Nr.) |
 copernicus.org/acp-14-12055-2014.pdf |
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| Zusammenfassung |
| Hygroscopic growth of aerosol particles can significantly affect their
single-scattering albedo (ω), and consequently alters the aerosol
effect on tropospheric photochemistry. In this study, the impact of aerosol
hygroscopic growth on ω and its application to the NO2 photolysis
rate coefficient (JNO2) are investigated for a typical aerosol
particle population in the North China Plain (NCP). The variations of aerosol
optical properties with relative humidity (RH) are calculated using a
Mie theory aerosol optical model, on the basis of field measurements of
number–size distribution and hygroscopic growth factor (at RH values above
90%) from the 2009 HaChi (Haze in China) project. Results demonstrate that
ambient ω has pronouncedly different diurnal patterns from ω
measured at dry state, and is highly sensitive to the ambient RHs. Ambient
ω in the NCP can be described by a dry state ω value of 0.863,
increasing with the RH following a characteristic RH dependence curve. A
Monte Carlo simulation shows that the uncertainty of ω from the
propagation of uncertainties in the input parameters decreases from 0.03 (at
dry state) to 0.015 (RHs > 90%). The impact of hygroscopic
growth on ω is further applied in the calculation of the radiative
transfer process. Hygroscopic growth of the studied aerosol particle
population generally inhibits the photolysis of NO2 at the ground level,
whereas accelerates it above the moist planetary boundary layer. Compared
with dry state, the calculated JNO2 at RH of 98% at the
height of 1 km increases by 30.4%, because of the enhancement of
ultraviolet radiation by the humidified scattering-dominant aerosol
particles. The increase of JNO2 due to the aerosol hygroscopic
growth above the upper boundary layer may affect the tropospheric
photochemical processes and this needs to be taken into account in the
atmospheric chemical models. |
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