Concurrence of Blowing Snow and Polynya Enhances Arctic Surface–Atmosphere Interaction: A Modeling Study With an Extreme Wind Event in 2018
Extreme wind events driven by cyclones and anticyclones can break up winter sea ice, leading to the occurrence of polynya, and blow surface snow into the atmosphere, causing snow sublimation in the air. Blow-snow-induced increase in humidity and low-level clouds results in an increased downward longwave radiation, warming the surface and sustaining polynya and, in turn, enhancing atmosphere-sea ice-ocean interactions.
Blowing snow processes is an emerging topic and has not been incorporated into the state-of-the-art Earth System models. The coupled WRF-blowing snow modeling study here suggests that blowing snow processes is important for improving understanding of the Arctic surface energy budgets and atmosphere-sea ice-ocean feedbacks.
Snow, a critical element influencing the surface energy/mass balance of the Arctic, can also drift in the air to complicate the surface–atmosphere interaction. This complexity can be further enhanced when the surface includes polynya. These processes, however, have not been well studied and are often unrepresented in climate and weather models. We address this by applying a snow/ice-enhanced version of the Weather Research and Forecasting model to examine the impacts of blowing snow and polynya on the surface–atmosphere interaction during an extreme Arctic wind event in February 2018, when an unprecedented polynya occurred off the north coast of Greenland. The results indicate that blowing snow and the polynya contribute opposite signs to the changes of surface sensible/latent heat fluxes, but both cause enhanced downwelling longwave radiation. Process analysis shows that the thermodynamic moistening/cooling effects due to the blowing snow sublimation are amplified by increased surface winds, reduced temperature inversion, and upward wind anomaly associated with the polynya. Enhanced surface–atmosphere interaction over a polynya due to blowing snow sublimation can potentially sustain the continuing development of the polynya.