Dispersion of Droplet Clouds in Turbulence

Pair dispersion in turbulence

We study the statistics of pair dispersion in two-dimensional turbulence. Direct numerical simulations show that the pdf of pair separations is in agreement with the Richardson prediction. The pdf of doubling times follows dimensional scaling and shows a long tail which is the signature of close approaches between particles initially seeded with a large separation. This phenomenon is related to...

Effects of Spectral Dispersion of Cloud Droplet Size Distributions on Radiative Properties of Clouds and Dispersion Forcing

where L is the liquid water content, and ρw is the density of water. In effect, these studies implicitly assume the only effect of aerosols on cloud microphysical properties is to increase N, and re can be parameterized by Eq. (1) for monodisperse droplet size distributions. Eq. (1) has also been used in the parameterization of re. However, available data suggests the spectral shape of the clou...

Towards quantifying droplet clustering in clouds

Droplet positions in atmospheric clouds are random but possibly correlated on some scales. This ‘clustering’ must be quantiŽ ed in order to account for it in theories of cloud evolution and radiative transfer. Tools as varied as droplet concentratio n power spectrum, Fishing test, and fractal correlation analysis have been used to describe the small-scale nature of clouds, and it has been difŽ ...

Turbulence and Dispersion

Wavelet analysis of turbulence in cirrus clouds

Two ̄ights of the UKMeteorological Oce's Hercules aircraft through daytime frontal cirrus around Scotland have been analysed using wavelet analysis on the vertical velocity time-series from the horizontal runs. It is shown that wavelet analysis is a useful tool for analysing the turbulence data in cirrus clouds. It ®nds the largest scales involved in producing turbulence, as does Fourier analy...