Dynamics and Chemistry of Marine Stratocumulus—DYCOMS-II

Abstract

The second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field study is described. The field program consisted of nine flights in marine stratocumulus west-southwest of San Diego, California. The objective of the program was to better understand the physics and dynamics of marine stratocumulus. Toward this end special flight strategies, including predominantly nocturnal flights, were employed to optimize estimates of entrainment velocities at cloud-top, large-scale divergence within the boundary layer, drizzle processes in the cloud, cloud microstructure, and aerosol-cloud interactions. Cloud conditions during DYCOMS-II were excellent with almost every flight having uniformly overcast clouds topping a well-mixed boundary layer. Although the emphasis of the manuscript is on the goals and methodologies of DYCOMS-II, some preliminary findings are also presented-the most significant being that the cloud layers appear to entrain less and drizzle more than previous theoretical work led investigators to expect.