Effect of the atmospheric stability condition on buoyant plume dynamics

Buoyant plumes from various geophysical events significantly contribute to atmospheric pollution, affecting air quality, human health, and ecosystems. Understanding the dispersion dynamics of these plumes is essential for managing their environmental impacts and improving predictive models. Plume behavior is strongly influenced by the stability conditions of the atmospheric boundary layer, which vary between day and night due to diurnal changes in the Earth's surface temperature. During the daytime, solar heating creates an unstable boundary layer, often extending to several kilometers in height, while at night, radiative cooling leads to a stable boundary layer, typically a few hundred meters deep with weaker turbulence. Using large-eddy simulations, this study investigates how these diurnal variations in atmospheric stability affect the dynamics and dispersal behavior of turbulent plumes in crossflows. The results indicate that the plume's energy content and decay are highly influenced by the state of the atmospheric stratification, leading to distinctive patterns of dispersion, entrainment, and spread. By understanding the mechanisms governing the behavior of plumes, this study aims to contribute to better planning, management, and mitigation of their adverse effects.