UAH

Jang-Tai Lin

The Effect of Inertial and Turbulence Oscillations in the Stable Boundary Layer and Their Role in Horizontal Dispersion

This research is to examine the role of inertial oscillations in affecting horizontal dispersion of pollutants and the parameter space and cause of the turbulent oscillations in the nocturnal boundary layer.

A coupled meoscale model and Lagrangian particle model are used to investigate the horizontal dispersion of pollutants. The coupled models show that the amplitude and the effective time of inertial oscillations are the main cause of nocturnal accelerating dispersion. An analytical model is introduced to investigate the role of inertial oscillations in influencing the horizontal dispersion. It was able to reproduce the magnitude and phase of the inertial oscillations reasonably well by the semi-empirical approach and shows that the nocturnal accelerating dispersion due to the inertial oscillations plays the key role in controlling the horizontal dispersion which is in agreement with the numerical results.

In the study of turbulent bursting events in the nocturnal boundary layer a simple one-dimensional nocturnal boundary later model is developed to examine the parameter space and cause of the oscillation. It shows that the roots of the oscillations are in a nonlinear interaction between the surface and the atmosphere. The magnitude of geostrophic wind and the heat capacity of the soil were found to play important roles in causing the breakdown of the nocturnal boundary layer.