ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-7-7535-2007 Contribution of mixing in the ABL to new particle formation based on some observations Lauros J. 1 2 Nilsson E. D. 2 Dal Maso M. 1 Kulmala M. 1 Division of Atmospheric Sciences, Department of Physical Sciences, POB 64, 00014 University of Helsinki, Finland Department of Applied Environmental Science, Stockholm University, 10691 Stockholm, Sweden 30 05 2007 7 3 7535 7567 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/7/7535/2007/acpd-7-7535-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/7/7535/2007/acpd-7-7535-2007.pdf

The connection between new particle formation and micro- and mesoscale meteorology was studied based on measurements at SMEAR II station in Southern Finland. We analyzed turbulent conditions described by sodar measurements and utilized these combined with surface layer measurements and a simple model to estimate the upper boundary layer conditions. Turbulence was significantly stronger on particle formation days and the organic vapor saturation ratio increase due to large eddies was stronger on event than nonevent days. We examined which variables could be the best indicators of new particle formation and concluded that the formation probability depended on the condensation sink and temporal temperature change at the top of the atmospheric boundary layer. Humidity and heat flux may also be good indicators for particle formation.

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