Convective Activities Within the Stratocumulus-Topped Boundary Layer

摘要

This study utilizes aircraft measurements obtained off the California coast to analyze the geometric, thermodynamic, and micro physical characteristics of convective updrafts and down drafts in the stratocumulus- topped boundary layer (BL). The vertical structure of thermodynamic and micro physical properties is consistent. The difference in peak droplet concentration between updrafts, down drafts, and the defined environment increases near the cloud top. We observe larger mean droplet diameters in down drafts near the cloud top, as the number of small droplets in cloud top down drafts appears to decrease. The horizontal variability seen in the cloud droplet spectra and micro physics properties is likely due to aerosol activation and growth in updrafts, cloud top entrainment, and penetrating cumulus. We compute the mass flux, using a mass flux parameterization. Several measured variables produce consistent results and agree with mass flux calculations from other stratocumulus datasets.