VOCALS: Atmospheric Sulfur Chemistry in the South East Pacific

Drexel University, Philadelphia PA

Investigators

Abstract

The focus of this research is on gas-phase sulfur measurements over the southeast Pacific (SEP) during the 2008 VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment) project. The chemistry of sulfur and its influence on processes controlling cloud properties in the SEP will be studied with fast measurements of dimethylsulfide (DMS) and sulfur dioxide (SO2) by atmospheric pressure ionization mass spectrometry; both concentrations and vertical fluxes of these species will be obtained. The investigators will study the changes in photochemistry occurring during transitions from cloudy to cloud-free conditions. A major goal is to evaluate the chemical processes of aerosol growth, cloud formation, and precipitation in the context of other physical and chemical data obtained in VOCALS, in order to better understand the factors controlling the static and dynamic properties of stratocumulus clouds. The data will also be used to identify the relative roles of anthropogenic and natural sources of sulfur gases. This research will help to elucidate the impact of sulfur chemistry on climate in the background atmosphere. Some of the results will be used in graduate courses on atmospheric chemistry and kinetics. One graduate student will be supported through this project.