The influence of an Antarctic glacier tongue on near‐field ocean circulation and mixing

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Stevens, CL, McPhee, MG, Forrest, AL, Leonard, GH, Stanton, T, Haskell, TG
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2014
• Subjects: Life Below Water; glacier tongue; Antarctica; ocean mixing; blocking; turbulence; supercooling; Geophysics; Oceanography; Physical Geography and Environmental Geoscience; Antarc*; Antarctic; Erebus Glacier; Ice Sheet
• Online Access: https://escholarship.org/uc/item/8kk25604; https://escholarship.org/content/qt8kk25604/qt8kk25604.pdf; https://doi.org/10.1002/2013jc009070

In situ measurements of flow and stratification in the vicinity of the Erebus Glacier Tongue, a 12 km long floating Antarctic glacier, show the significant influence of the glacier. Three ADCPs (75, 300, and 600 kHz) were deployed close (<50 m) to the sidewall of the glacier in order to capture near-field flow distortion. Scalar (temperature and conductivity) and shear microstructure profiling captured small-scale vertical variability. Flow magnitudes exceeded 0.3 m s-1 through a combination of tidal flow (8 cm s-1) and a background/residual flow (4-10 cm s-1) flowing to the NW. Turbulence was dominated by deeper mixing during spring tide, likely indicative of the role of bathymetric variation which locally forms an obstacle as great as the glacier. During the neap tide, near-surface mixing was as energetic as that seen in the spring tide, suggesting the presence of buoyancy-driven near-surface flows. Estimates of integrated dissipation rate suggest that these floating extensions of the Antarctic ice sheet alter energy budgets through enhanced dissipation, and thus influence coastal near-surface circulation. Key Points A blocking layer is generated by the floating glacier Tidal rectification or substantial residual flow results in tidal asymmetry Upper water column mixing is at least as strong during neap tides as spring © 2014. American Geophysical Union. All Rights Reserved.