High-latitude cabbeling observations along the east Greenland polar front

McGraw, Kevin, Morley, Audrey, & Ward, Brian. (2025). High-Latitude Cabbeling Observations Along the East Greenland Polar Front. Journal of Geophysical Research: Oceans, 130(7), e2025JC022567. https://doi.org/10.1029/2025JC022567

Abstract

Cabbeling is the process where water parcels of the same density but different temperatures/salinities combine to form a new parcel of higher density. This can result in a statically stable profile becoming unstable after mixing has occurred. High-latitude cold, fresh, and shallow ocean waters exhibit greater nonlinearity in density dependence on temperature and are prone to cabbeling along fronts. While modeling shows there are important implications of high-latitude cabbeling, harsh polar conditions and the evanescent nature of cabbeling events make direct observations of the small-scale and shifting vertical structure difficult and rare. The East Greenland Polar Front (EGPF), where mixing of cold-fresh Arctic water and warmer-saltier Atlantic water occurs, is a location which has a high potential for cabbeling. Cabbeling-induced density anomalies of up to 0.05 kg m−3 within the upper 40 m were observed along the EGPF in 2023. Shallow stratification shows staircase structures within a strong halocline overlaying warm water intrusions, displaying a characteristic “jagged” shape in TS space. Enhanced turbulence was identified in regions where cabbeling instabilities occurred. These observations offer new insight into the vertical and temporal structure of cabbeling in high-latitude environments via rapidly repeated profiling. The observed anomalies align in magnitude and character with previously documented studies, extended here to include shallower observations coupled with shear measurements within frontal zones as identified by sea surface temperature. These findings suggest that cabbeling-induced mixing moderates locally enhanced heat flux, with implications for ice-ocean interaction and the broader high-latitude climate system.

Funder

Research Ireland
European Union's Horizon 2020
Marine Institute
Geological Survey of Ireland

Publisher

American Geophysical Union and Wiley

Rights

CC BY-NC-ND

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Collections

Earth and Ocean Sciences (Scholarly Articles)