Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 6 2005 10.5194/acpd-5-11413-2005 http://www.atmos-chem-phys-discuss.net/5/11413/2005/ http://www.atmos-chem-phys-discuss.net/5/11413/2005/acpd-5-11413-2005.html http://www.atmos-chem-phys-discuss.net/5/11413/2005/acpd-5-11413-2005.pdf 11413 11487 2005-11-10 Conceptual study on nucleation burst evolution in the convective boundary layer – Part I: Modelling approach O. Hellmuth olaf@tropos.de Modelling Department, Institute for Tropospheric Research, Permoser Str. 15, 04318 Leipzig, Germany A high-order modelling approach to interprete 'continental-type' particle formation bursts in the anthropogenically influenced convective boundary layer (CBL) is proposed. The model considers third-order closure for planetary boundary layer turbulence, sulfur and ammonia chemistry and aerosol dynamics. In part I of the present paper, previous observations of ultrafine particle evolution are reviewed, model equations are derived, the model setup for a conceptual study on binary and ternary homogeneous nucleation is defined, and shortcomings of process parameterization are discussed. In subsequent parts of the paper simulation results obtained within the framework of a conceptual study on the CBL evolution and new particle formation (NPF) will be presented and compared with observational findings.