Overview of the Cumulus Humilis aerosol processing study

Document Type


Publication Date



The Cumulis Humilis Aerosol Processing Study (CHAPS) campaign was designed to collect observations relevant to a number of issues related to aerosols and clouds, including differences in below-cloud aerosol optical and cloud nucleating properties downwind of Oklahoma City, the distribution of aerosol extinction in the vicinity of shallow clouds and differences in aerosol extinction in the vicinity of shallow clouds. CHAPS utilized a sampling strategy closely linking the DOE G-1, the National Aeronautics and Space Administration (NASA) B200 aircraft and primary and secondary surface sites. Observations of boundary layer aerosols and meteorological conditions were made at the primary surface site just north of Oklahoma City and sky cover was measured at a nearby secondary surface site. The sampling streams from both the inlets fed into essentially identical instrument systems for measuring the particles optical properties. The observed data is useful for in-depth analysis, including model studies related to the activation of aerosols as they are lifted up from the convective boundary layer into the clouds.

Publication Title

Bulletin of the American Meteorological Society