The effect of atmospheric waves on aerosol nucleation and size distribution

Abstract

Atmospheric waves can enhance the aerosol particle nucleation rate up to 5 orders of magnitude because of the strongly nonlinear effect of temporal fluctuations in temperature and vapor pressures on the nucleation rate. The wave amplitude is the most important wave characteristic controlling the mean nucleation rate and net particle number concentration. A simple parameterization of the enhancement in nucleation rate can be given at certain mean conditions. The enhancement is from 1 to 5 orders of magnitude if the temperature amplitude is 5 K. Since nucleation causes a wave periodicity in the aerosol number only for particles below 3nm diameter, which is typically the lower cut for particle counters, it will be difficult to directly observe the effect of wave or eddy variability on the number of near‐nanometer size particles. In larger particles the waves will cause an increase in the mean number concentration. It is also difficult to observe a difference between the influence of nucleation on the number concentration and variations simply caused by vertical gradients in number concentration or fluxes of these particles.