Mixed-Layer Mode Simulation of Eastern North Pacific Stratocumulus

Abstract

The cloud-topped mixed-layer theory developed by Lilly (1968) is employed in a slightly generalized form to simulate stratocumulus in the eastern North Pacific. The radiation parameterization involves cloud-top longwave cooling and mixed-layer shortwave heating. Long-wave emissivity and shortwave absorption are functions of cloud thickness. The model is integrated along climatological trajectories which traverse the area bounded by 145°W, 115°W, 20°N and 40°N. The results of the integration include fields of cloud-top and cloud-base height, mixed-layer thermodynamic structure, and convective and radiative fluxes. Where it is possible to compare model-generated fields with the observations of Neiburger et al. (1961), general agreement is found. The model-predicted location of the southern limit (due to cloud-top instability) of stratocumulus clouds is in agreement with observations.