Wave-cloud dynamics in the atmospheric boundary layer

We study the impact of gravity waves in the stratocumulus-topped boundary layer (STBL) using large-eddy simulation with moisture physics. The gravity waves are excited via an imposed vertical momentum forcing which mimics the form of a plane wave packet. In the limit of a dry and uniformly stratified setup, the forcing recovers the classical internal wave dispersion relation.



Key parameters of interest are the amplitude, period, and locality of the gravity wave forcing; baseline values of these characteristics are estimated from previous satellite measurements. The resulting sweep is quantified in terms of cloud breakup propensity relative to our novel radiative-convective equilibrium STBL framework. Nondimensional analysis revealed a critical amplitude for initiating breakup and, after normalizing by wave energy, shorter frequency and multiperiod forcings led to sustained patchy cloud decks. Lastly, we explore the connection between the change in the liquid water path and the generation of turbulent kinetic energy due to buoyancy and shear.