Particle formation at a continental background site: comparison of model results with observations

[摘要] At Hohenpeissenberg(47° 48' N, 11° 07' E, 988 m asl), a rural site 200--300~m higher than the surrounding terrain, sulphuricacid concentrations, particle size distributions, and other trace gas concentrations were measured over a two and a half yearperiod. Measured particle number concentrations and inferred particlesurface area concentrations were compared with box-model simulations for 12 carefully selected data setscollected during the HAFEX experiment (Birmili et al., 2003). The 12 caseswere selected after meteorological and aerosol dynamical criteria in order to justify the use of a box-model. The aerosol modelincluded a binary sulphuric acid water nucleation scheme. Calculated nucleation rates were corrected with a factor to matchmeasured and calculated particle number concentrations. For the investigated 12 data sets,the correction factors were smallest for measurements made under stable thermal stratification and low wind conditions, i.e.conditions that are frequently encountered during winter. Correction factors were largest for measurements made under strongconvective conditions.

Our comparison of measured and simulated particle size distributions suggests that the particle formation process maybestrongly influenced by mixing processes driven by thermal convection and/or wind sheer.

[学科分类] 大气科学