Analysis of diurnal trends in stratocumulus drizzle from the VOCALS field campaign

The Southeast Pacific deck of stratocumulus clouds is one of various existing regions of stratocumulus which form off the west coast of continents. These regions of clouds reflect incoming radiation, producing a net cooling effect on the climate. An understanding of the dynamics of these clouds can result in an improvement of global climate models.

In this research we intended to find diurnal trends in marine stratocumulus drizzle utilizing ship-based radar observations obtained during the 2008 VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment (VOCALS-REx). Radar images were classified by intensity of reflectivity and the amount of area said reflectivity covered. Additionally, satellite infrared (IR) data was utilized to classify the clouds according to the amount of coverage, or if it was found in a transitional region between open and closed cellular cloud structures. Preliminary results show evidence of a diurnal cycle of reflectivity intensity, discrete drizzle cell size, and amount of cells. However, the strength of diurnal trends is reduced further east closer to the Chilean coast.