VOCALS: Cloud Chemistry Measurements in the Southeast Pacific

Colorado State University, Fort Collins CO

Investigators

Abstract

An airborne cloud water collector will be deployed on the NSF/NCAR C-130 aircraft to study marine cloud composition and aerosol-cloud interactions in the 2008 VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment) project. The focus of VOCALS is to improve model simulations and predictions of the climate system in the Southeast Pacific (SEP). Multiple cloud water samples will be collected on approximately 10-12 VOCALS flights. These samples will be chemically analyzed for a wide variety of major and trace species including chloride, sulfate, nitrate, sodium, other ions, total organic carbon (TOC), partially oxidized sulfur compounds, hydrogen peroxide (H2O2), and a range of carboxylic acids. These measurements will provide information on the composition of clouds both near shore and further west in the SE Pacific, a region with few previous observations of marine cloud chemistry. Characterization of sulfur oxidation chemistry within clouds is key to understanding and modeling the lifetimes of sulfur dioxide (SO2) in this region in order to improve our understanding of whether SO2 oxidized in the gas phase to sulfuric acid (H2SO4) followed by nucleation of new particles in pockets of open cells (POCs) is likely to be of local biogenic or more distant anthropogenic origin. Broader impacts include the education and training of one graduate student, who will gain a unique set of skills related to cloud chemistry and benefit from broader exposure to this large, international experiment. Project results will be incorporated into educational materials to be shared with students and the community at a range of educational levels. The participants also plan to participate in broader educational and outreach activities currently being planned in conjunction with the VOCALS-REx field experiment.