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Polar lows (PLs) are intense, high-latitude mesoscale weather systems that develop over oceanic areas near the polar regions during the cold season. Due to their association with severe weather conditions, they can significantly impact human life and socioeconomic activities. However, their small size, short lifespan, and limited observational data make forecasting PLs particularly challenging. Moreover, the complex physical mechanisms underlying their formation and intensification remain insufficiently understood, highlighting the need for further investigation.

The ocean plays a critical role in PL development, making an accurate representation of air-sea heat fluxes essential for enhancing forecasts and improving numerical simulations. Intense PLs are often accompanied by localized gale-force winds (>30 m/s), which can extract substantial heat (>1000 W/m²) from the ocean, sufficient to leave pronounced effects on the underlying ocean. Given the strong interactions between PLs and the ocean, this thesis aims to address key knowledge gaps in this field.

Sea spray, generated by wave breaking under high wind conditions, significantly influences turbulent heat fluxes at the air-sea interface. The first part of this thesis investigates the impact of spray-mediated heat fluxes on PLs through an atmosphere-wave coupled model. Results indicate that spray-enhanced sensible heat fluxes play a crucial role in PL development, whereas spray-enhanced latent heat fluxes have a relatively minor effect. Beyond sea spray, the ocean surface contains mesoscale structures such as eddies and fronts, which create mesoscale sea surface temperature anomalies. These anomalies can also influence air-sea turbulent heat and momentum fluxes, thereby favoring the intensification of PLs, as explored in the second part of this thesis. The third part of this thesis examines the impact of PLs on the global ocean. The findings indicate that the oceanic response to PLs exhibits strong regional variability. The Atlantic Ocean emerges as the most sensitive region.

In the context of global warming, PL activity is expected to shift poleward as the sea ice edge retreats to higher latitudes, resulting in a reduced frequency of occurrence. However, the response of individual PL development to a warming climate remains uncertain. The final part of this thesis addresses this uncertainty by applying a pseudo-global warming approach to investigate how individual PLs respond to climate change. The results reveal a general weakening of PL intensity under warmer conditions, reflected in lower maximum surface wind speeds and higher minimum sea level pressure. Nevertheless, PL-associated precipitation is projected to intensify, primarily due to increased latent heat release in a warmer atmosphere.