Wintertime In Situ Cloud Microphysical Properties of Mixed-Phase Clouds Over the Southern Ocean

Abstract

In situ observations made over 20 flights during three Austral winters (June to October 2013–2015) were analyzed to characterize the cloud microphysical properties and natural variability of mid-latitude shallow convective clouds over the Southern Ocean (SO), with a focus on pristine conditions and the mixed-phase temperature range (MPTR, 0°C to −31°C). Liquid, mixed-phase, and ice cloud fractions were observed 39%, 44%, and 17% of the time, respectively, under various meteorological settings. Liquid phase clouds were typically characterized by low droplet number concentrations and the common presence of drizzle. Supercooled liquid water was prevalent in the MPTR, while freezing of supercool..