CSTRIPE: Coastal Stratocumulus Imposed Perturbation Experiment

Summary

CSTRIPE is field experiment designed to quantify the effect aerosol has on the microphysics, precipitation and dynamics of marine stratocumulus (MSc). The CIRPAS Twin Otter aircraft will be deployed in a three week mission off the coast of Monterey, California in July, 2003. The strategy is a blend from two previous field experiments, MAST and ACE-2, that were directed towards aerosol-MSc interactions. MAST (Monterey Area Ship Track Experiment) was successful in that it targeted ship tracks. Use of a localized aerosol perturbation, such as ship tracks, obviates the difficulty of separating aerosol-forced signals from meteorologically forced signals. ACE-2 (The second Aerosol Characterization Experiment) was successful in that it used a number of well articulated closure studies to evaluate state-of-the-art models including: hygroscopic and CCN activity of aerosol; cloud activation; the effect of entrainment mixing on the vertical and horizontal distribution of cloud microphysics; and the link between cloud microphysics and the radiative properties of the clouds (i.e. both albedo and bidirectional reflectance used by satellites to retrieve cloud optical properties). By using both a closure strategy, as in ACE-2, and the contrast provided by a localized aerosol perturbation, as in MAST, it is hoped to achieve an unprecedented degree of success with relatively modest resources. A new element added to the strategy is the use of hygroscopic cloud seeding flares as a controlled and well characterized perturbation. CSTRIPE is supported by the Office of Naval Research.