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

In situ observations made over 20 flights during three Austral winters (June to October 2013–2015) were analyzed characterize the cloud microphysical properties and natural variability of mid-latitude shallow convective clouds Southern Ocean (SO), with a focus on pristine conditions mixed-phase temperature range (MPTR, 0°C −31°C). Liquid, mixed-phase, ice fractions observed 39%, 44%, 17% time, respectively, under various meteorological settings. Liquid phase typically characterized by low droplet number concentrations common presence drizzle. Supercooled liquid water was prevalent in MPTR, while freezing supercooled raindrops likely formed primary nucleation mechanism these clouds. Ice particles habits present mature/maturing cells, suggesting operation multiple particle growth regimes. Increased (exceeding 100 L−1), well excess expected nuclei concentrations, measured at warmer than approximately −12°C, signaling secondary production mechanisms. However, segments spatiotemporally inhomogeneous, chaotic turbulent nature ice-forming processes. Accurately representing processes global models, necessary, is challenge. Our analysis also found marked inconsistencies between several satellite-based products that have underpinned recent developments model parameterization frameworks. Understanding addressing are critical toward improving representation SO their radiative climate models.