Atmospheric Influence of Summer Monsoon on Sea Ice Variability

The impacts of tropical systems on polar sea ice have been relatively underestimated, which could potentially offer insights into the mechanisms driving sea ice variability and enhance predictive skills regarding sea ice extent. Our recent study delves into the influence of July-August Indian Summer Monsoon (ISM) precipitation on shaping Arctic sea ice variability from August to October, alongside exploring how the December-February Australian Summer Monsoon (AUSSM) modulates simultaneous Antarctic sea ice. Our findings suggest that ISM could explain up to 20% of Arctic sea ice concentration (SIC) variance across the marginal Arctic Ocean, while AUSSM could account for roughly 10% of SIC variance in the Pacific sector of the Southern Ocean including Amunsen and Ross Seas. Insights from both observation and model experiments demonstrate that the diabatic heating associated with ISM and AUSSM can trigger the poleward propagation of Rossby waves, culminating in barotropic anomalous circulations over the Arctic and Antarctic regions. These anomalous atmospheric patterns, characterized by highs and lows, have the potential to influence surface downwelling longwave radiation and surface winds, thereby shaping sea ice variability through a combination of thermodynamic and dynamic processes.