The MAGIC Marine Boundary Layer Campaign: The Mean Thermodynamic and Cloud State

Subtropical marine stratocumulus extent and opacity plays a key role in climate sensitivity, and representing these clouds remains a major challenge for climate models. We present an overview of the mean physical structure of the marine boundary layer in the subtropical Northeast Pacific, using data taken during the container-ship-based Marine ARM GPCI Investigation of Clouds (MAGIC) campaign. MAGIC carried the second ARM mobile facility (AMF2) over the ocean between Los Angeles and Honolulu nearly forty times between September 2012 and October 2013. This region shows a mean cloud transition following the trade winds, from a stratocumulus-topped boundary layer capped with a strong inversion near California to a deeper boundary layer with trade cumulus clouds near Hawaii. We present MAGIC measurements of precipitation, liquid water path, cloud fraction, thermodynamic and wind profiles, boundary layer height, inversion strength, and surface properties. We place these results from MAGIC within the context of other prior measurements from the literature.