Contribution of mixing in the ABL to new particle formation based on observations

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

SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions, transport and chemistry in the ABL in and above a vegetation canopy using tower measurements from the SMEAR II at Hyytiälä, Finland and available soundings data from neighbouring meteorological stations. Using the sounding data for upper boundary condition and nudging the model to tower measurements in the surface layer we were able to get a reasonable description of turbulence and other quantities through the ABL. As a first application of the model, we present vertical profiles of organic compounds and discuss their relation to newly formed particles

Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the simulated vertical profile of particle number concentration does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by the biosphere. <br><br> The simulation of aerosol concentration within the atmospheric boundary layer during nucleation event days shows a highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated the suitability of our turbulent mixing scheme in reproducing the most important characteristics of particle dynamics within the boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles in the lowest part of the atmospheric boundary layer

Notes et informations

Lauros J., Servière D. Notes et informations. In: Échos d'Orient, tome 16, n°102, 1913. pp. 461-468

Notes et informations

Lauros J., Servière D. Notes et informations. In: Échos d'Orient, tome 16, n°102, 1913. pp. 461-468

SOSA - A new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL - Part 1: Model description and initial evaluation

Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions, transport and chemistry in the ABL in and above a vegetation canopy using tower measurements from the SMEAR II at Hyytïal̈a, Finland and available soundings data from neighbouring meteorological stations. Using the sounding data for upper boundary condition and nudging the model to tower measurements in the surface layer we were able to get a reasonable description of turbulence and other quantities through the ABL. As a first application of the model, we present vertical profiles of organic compounds and discuss their relation to newly formed particles. © 2011 Author(s)