Early Stages in the Lifecycle of Polar Liquid-Bearing Clouds

Abstract

Stratiform clouds consisting of water droplets are ubiquitous over the polar regions, where in response to the prevalent sub-freezing temperatures, they often induce the formation and growth of ice crystals. These polar clouds contribute to surface warming and affect the distribution of heat in the atmospheric, with direct implications for the resilience of the polar ice pack. However, the physical representation of these clouds is still a major challenge for models trying to predict future climate. A significant fraction of the lifecycle of these polar clouds, which occasionally persist for multiple days, is often manifested in a self-sustaining and turbulent state, driven by radiative cooling of the clouds. This self-sustaining cloud lifecycle stage has been thoroughly investigated in numerous studies. However, the preceding cloud lifecycle stages, which may last up to several hours, have remained widely overlooked. These preceding stages commence at cloud formation, often in a stable and non-turbulent atmospheric layer, and serve as a key junction between cloud persistence and cloud dissipation. These two contrasting cloud lifecycle trajectories pose the question if large scale models that emulate the behavior of the atmosphere can develop a similar cloud lifecycle characteristics for the real physical reasons. Addressing this question can, therefore, increase our confidence in climate projections at these times when the polar climate is continuously changing.

The purpose of this research is to improve the characterization and understanding of these early stages in the lifecycle of polar stratiform clouds consisting of water droplets and to aid their representation in large-scale models. This research will largely rely on the most comprehensive, full-year measurements of atmospheric variables over the Arctic ice pack to date, currently taking place over the high Arctic as part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAIC) field campaign.