Influence of sea ice and Greenland’s topography on polar low cases in the Greenland Sea

Abstract

This study investigates how sea ice concentration and Greenland’s topography influence the development, structure, and intensity of polar lows along Greenland’s east coast under similar synoptic forcing. As Arctic sea ice declines and maritime activity expands, these short-lived but hazardous mesoscale cyclones pose a growing risk to Arctic operations. Three polar low events were simulated using Polar WRF, comparing a five-member Control ensemble with sensitivity experiments in which sea ice was removed, its concentration and thickness were increased, or Greenland’s topography was flattened. Atmospheric initial and lateral boundary conditions were held fixed across experiments, so that differences reflect the response to prescribed surface changes. The results indicate that meso- α -scale forcing provides the primary framework for storm formation and that sea ice concentration influences intensification by altering surface turbulent heat fluxes. Reduced ice cover enhanced these fluxes and deepened central pressure, with weaker, less consistent changes in near-surface winds and low-level vorticity, whereas increased ice cover suppressed intensification more uniformly and in some cases delayed peak intensity. Enhanced fluxes also extended the vorticity and ascent column upward, producing a more vertically coherent vortex, whereas suppressed fluxes confined the response to the lower troposphere. Sensitivity was greatest when storms developed near the marginal ice zone during early growth, while those encountering the ice edge later showed weaker responses. Greenland’s topography primarily acted on storm organization. Where cyclogenesis occurred near the coast, removing the topography left the circulation embedded within a broader synoptic trough rather than a discrete coastal vortex.