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| Titel |
Development and evaluation of the aerosol dynamics and gas phase chemistry model ADCHEM |
| VerfasserIn |
P. Roldin, E. Swietlicki, G. Schurgers, A. Arneth, K. E. J. Lehtinen, M. Boy, M. Kulmala  |
| 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 ; 11, no. 12 ; Nr. 11, no. 12 (2011-06-22), S.5867-5896 |
| Datensatznummer |
250009863
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| Publikation (Nr.) |
 copernicus.org/acp-11-5867-2011.pdf |
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| Zusammenfassung |
| The aim of this work was to develop a model suited for detailed studies of
aerosol dynamics, gas and particle phase chemistry within urban plumes, from
local scale (1 × 1 km2) to regional scale. This article describes and
evaluates the trajectory model for Aerosol Dynamics, gas and particle phase
CHEMistry and radiative transfer (ADCHEM). The model treats both vertical
and horizontal dispersion perpendicular to an air mass trajectory (2-space
dimensions). The Lagrangian approach enables a more detailed representation
of the aerosol dynamics, gas and particle phase chemistry and a finer
spatial and temporal resolution compared to that of available regional
3D-CTMs. These features make it among others well suited for urban plume
studies. The aerosol dynamics model includes Brownian coagulation, dry
deposition, wet deposition, in-cloud processing, condensation, evaporation,
primary particle emissions and homogeneous nucleation. The organic mass
partitioning was either modeled with a 2-dimensional volatility basis set
(2D-VBS) or with the traditional two-product model approach. In ADCHEM these
models consider the diffusion limited and particle size dependent
condensation and evaporation of 110 and 40 different organic compounds
respectively. The gas phase chemistry model calculates the gas phase
concentrations of 61 different species, using 130 different chemical
reactions. Daily isoprene and monoterpene emissions from European forests
were simulated separately with the vegetation model LPJ-GUESS, and included
as input to ADCHEM. ADCHEM was used to simulate the ageing of the urban
plumes from the city of Malmö in southern Sweden (280 000 inhabitants).
Several sensitivity tests were performed concerning the number of size bins,
size structure method, aerosol dynamic processes, vertical and horizontal
mixing, coupled or uncoupled condensation and the secondary organic aerosol
formation. The simulations show that the full-stationary size structure
gives accurate results with little numerical diffusion when more than 50
size bins are used between 1.5 and 2500 nm, while the moving-center method
is preferable when only a few size bins are selected. The particle number
size distribution in the center of the urban plume from Malmö was mainly
affected by dry deposition, coagulation and vertical dilution. The modeled
PM2.5 mass was dominated by organic material, nitrate, sulfate and ammonium.
If the condensation of HNO3 and NH3 was treated as a coupled
process (pH independent) the model gave lower nitrate PM2.5 mass than if
considering uncoupled condensation. Although the time of ageing from that
SOA precursors are emitted until condensable products are formed is
substantially different with the 2D-VBS and two product model, the models
gave similar total organic mass concentrations. |
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