Polar Lows and Their Effects on Sea Ice and the Upper Ocean in the Iceland, Greenland, and Labrador Seas

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(7)

Published: June 26, 2024

Abstract Using two case studies, we analyze the effects of explicitly resolving polar lows in a global climate model (ICON‐Sapphire) with high resolution 2.5 km on upper ocean and sea ice. We aim to understand mechanism how form coupled they interact When at ice edge, induce marine cold air outbreaks that lead large heat loss from ocean. This contributes dense water formation Iceland Greenland Seas, which replenishes climatically important Denmark Strait Overflow Water (DSOW). The wind speeds open leads polynyas cover, such as Sirius Polynya northeastern Greenland. Heat is compensated for by new ice, rejected brine densifies shelf. In Labrador Sea, intensify rapidly deepen mixed layer. Resolving kinematic features improves realism models, particular surface (sub)polar oceans.

Language: Английский

Consistent Seasonal Hydrography From Moorings at Northwest Greenland Glacier Fronts

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(9)

Published: Sept. 1, 2024

Abstract Greenland's marine‐terminating glaciers connect the ice sheet to ocean and provide a critical boundary where heat, freshwater, nutrient exchanges take place. Buoyant freshwater runoff from inland melt is discharged at base of glaciers, forming vigorous upwelling plumes. It understood that subglacial plumes modify waters near glacier fronts increase submarine by entraining warm ambient depth. However, observations along coastal margins remain biased toward summer months which limits accurate estimation forcing on retreat acceleration. Here, we fill key observational gap in northwest Greenland describing seasonal hydrographic variation Melville Bay using situ moorings deployed year‐round, CTDs, profiling floats. We evaluated local remote sensing reanalysis data products alongside high‐resolution model. Analysis year‐round revealed consistent above‐sill seasonality temperature salinity. The warmest, saltiest occurred spring (April–May) primed for enhanced when meltwater entrain deep waters. Waters were coldest freshest early winter (November–December) after sea ice, icebergs provided cold shelf. Ocean variability was greatest fall, coincident with increased large wind events before formation. Results our mechanistic understanding ice‐ocean interactions enable improvements model parameterization.

Language: Английский

Sea ice in the Nordic Seas: Greenland stadial to interstadial changes

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 343, P. 108916 - 108916

Published: Sept. 2, 2024

Sea ice conditions in the eastern Fram Strait between 40 and 36.5 ka b2k (thousand years before year 2000) are reconstructed detail, based on biomarker analyses. Following extensive sea around Greenland Interstadial 9/Greenland Stadial 9 transition at 39.9 b2k, repeated polynya activity marked Strait. Nearly perennial was observed 8 38.22 followed by a gradual establishment of seasonal cover over research area during 8. Previous studies highlighted retreat southeastern Nordic Seas as driver abrupt to climate change. We document intervals with less than previously suggested. By mapping variable extent 8, further constraints detected that may help define role driving change glacial times.

Language: Английский