The Role of Turbulence in Ice Microphysics and Sedimentation in Arctic Mixed‐Phase Clouds: Evidence From Yearlong Observations

Abstract

Despite the recognized importance of turbulence in Arctic mixed‐phase cloud (AMPC) persistence, its effects on ice microphysics and size‐dependent sedimentation remain poorly understood. Using yearlong shipborne MOSAiC observations, we examine these processes across eddy dissipation rate (EDR) ranges. The mixed‐phase layer base (MLB) shows relatively high EDR, with the highest range (10 ^−3.5 –10 ⁻²  m ²  s ⁻³ ) associated with lower temperatures ( T _MLB ). At the MLB, the typical relationship between particle size and ice sedimentation weakens as EDR increases. Under stronger turbulence, sedimentation is enhanced for layers with smaller particles but weakened for those with larger particles, a contrast broadly consistent with preferential sweeping and loitering. These sedimentation changes are accompanied by smaller ice particles in the less cold regime ( T _MLB  > −20°C) and higher ice particle concentrations in the colder regime ( T _MLB  < −20°C). Such sedimentation changes may influence AMPC microphysics and potentially contribute to ice‐recycling processes.