Temporal Evolution of Cloud Properties in Arctic Cold air Outbreak Cloud Streets

In this study, we examine the temporal evolution of Arctic cold air outbreak cloud streets and their effects on the atmospheric radiation budget over the Fram Strait. Utilizing observations from the HALO-(AC)³ aircraft campaign conducted in 2022, we analyze the structure, microphysical, and macrophysical properties of transitioning cloud streets and assess their radiative impacts. Our investigation explores how wind shear and buoyancy forces contribute to the shift from cloud street formations to isotropic cloud patterns, with a focus on how changes in wind speed and atmospheric stability, as indicated by the Richardson number, drive this transition. Results from our case study reveal that reduced wind speeds hinder cloud street formation, promoting isotropic cloud formations. This shift increases cloud fraction (from 0.73 to 0.84), cloud top height (from 330 m to 390 m), and liquid water path, alongside a rise in cloud particle concentrations within the 100 μm to 1000 μm size range. Radiative budget observations indicate that organized cloud streets exhibit higher albedo (0.45) and greater thermal infrared net irradiance (-133 W m⁻²) compared to isotropic clouds (0.35 and -139 W m⁻², respectively). Our findings highlight the importance of accurately representing these processes in climate models to enhance predictions of Arctic amplification and its influence on global climate systems.