The EPIC 2001 stratocumulus study

Abstract

As part of the EPIC 2001 stratocumulus study, comprehensive ship-based remote sensing and surface measurements were taken during a 2-week cruise through the southeast Pacific region during the month (October) when the stratocumulus clouds are most extensive. Scientific objectives included measuring the vertical structure of the atmospheric boundary layer (ABL), understanding what physical processes are determining the stratocumulus cloud albedo, and understanding the fluxes of heat and water that couple the atmosphere and the ocean in this region. An unexpectedly well-mixed stratocumulus-capped boundary layer capped by a strong inversion was encountered throughout. A strong diurnal cycle was observed, with thicker clouds and substantial drizzle during the late night and early morning. This was driven in part by local diabatic processes but was reinforced by a surprisingly pronounced diurnal cycle of vertical motion.