Monday, 10 January 2005
Measurements of marine stratocumulus cloud water composition over the Eastern Pacific Ocean
While marine cloud water has been sampled from a variety of locations around the world for composition analysis, the majority of these studies have been conducted from coastal locations or less than 200 km offshore. In many of these studies the air masses in which the sampled clouds reside was of either unknown, unreported, or continental origin, making it difficult to determine if the reported composition data are representative of clouds in the marine environment or if sampled clouds exhibit direct continental or anthropogenic influences. A recent cloud water sampling campaign has yielded in-situ composition data for stratocumulus clouds residing in the remote marine boundary layer. Fifty cloud water samples were obtained with an aircraft-based cloud water collection system jointly developed at Colorado State University and the National Center for Atmospheric Research (NCAR). The collector was deployed during the second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field project, and collected cloud water samples over the Pacific Ocean 400 km southwest of San Diego, CA. The result is a unique description of marine cloud water solute composition that includes pH, and concentrations of major inorganic ions, trace metals, formaldehyde, peroxides, S(IV), and total organic carbon.