Turbulent flux measurements of the near-surface and residual-layer small particle events

According to recent field studies, almost half of the New Particle Formation (NPF) events occur aloft, in a residual layer, near the top of the boundary layer. Therefore, measurements of the meteorological parameters, precursor gas concentrations, and aerosol loadings conducted at the ground level are often not representative of the conditions where the NPFs take place. This paper presents new measurements obtained during the Turbulent Flux Measurements of the Residual Layer Nucleation Particles, conducted at the Southern Great Plains research site. Vertical turbulent fluxes of 3–10 nm-sized particles were measured using a sonic anemometer and two condensation particle counters with nominal cutoff diameters of 3 nm and10 nm mounted at the top of the 10-m telescoping tower. Aerosol number size distribution (5 to 300 nm) was determined through the ground-based Scanning Mobility Particle Sizers. The size selected (15 to 50 nm) particle hygroscopicity was derived with the Humidified Tandem ...