Estimating sea-ice coverage, draft, and velocity in Marguerite Bay (Antarctica) using a subsurface moored upward-looking acoustic Doppler current profiler (ADCP)

Hyatt, Jason; Visbeck, Martin; Beardsley, Robert C.; Owens, W. Brechner

doi:10.1016/j.dsr2.2007.11.004

Cited by 19 publications

(23 citation statements)

References 17 publications

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“…The accuracy of the bottom track depth was estimated at 15 cm, based on a comparison with the mooring's pressure data. For more details on these methods, refer to Shcherbina et al [2005] and Hyatt et al [2008].…”

Section: Data Methods and Settingmentioning

confidence: 99%

Cross‐shelf transport of warm and saline water in response to sea ice drift on the Laptev Sea shelf

2013

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are used to describe recent changes in the Laptev Sea hydrography and to highlight wind-and ice-driven surface Ekman transport as the mechanism to translate these changes from the outer-to the inner-shelf bottom waters. In February 2010, moored oceanographic instruments recorded a sudden increase in temperature (+0.8 C) and salinity (+ >3) near the bottom of the inner Laptev Sea shelf. Such warm and saline waters had not been previously observed on the inner shelf in winter. They likely originated from the basin and were first observed during a summer 2009 CTD survey in the northwestern shelf break region, subsequently spreading east and shoreward across the Laptev Sea shelf. The changes were introduced to the mooring site by the first of a series of bottom-intensified flow events with velocities reaching 20 cm s À1 , topographically guided along a relic submarine river valley. Each of the flow events coincided with negative pressure anomalies at the mooring site and offshore-directed (upwelling-favorable) winds and ice drift. We suggest that the observations to first order resemble a simplified two-dimensional two-layered ocean, where offshore surface Ekman transport is compensated for by a barotropic shoreward response flow near the bottom. In this paper, we use one of the first comprehensive long-term Laptev Sea datasets to highlight ice-ocean-atmosphere interactions in early and late winter and discuss the role of freshwater, stratification, and ice mobility on under-ice circulation on the Laptev Sea shelf.Citation: Janout, M. A., J. Ho¨lemann, and T. Krumpen (2013), Cross-shelf transport of warm and saline water in response to sea ice drift on the Laptev Sea shelf,

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Section: Data Methods and Settingmentioning

confidence: 99%

Cross‐shelf transport of warm and saline water in response to sea ice drift on the Laptev Sea shelf

2013

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“…Both ice formation and breakup were observed directly during 2007, but no direct observations were available for 2008. Duration of the sea ice cover in 2008 was estimated from ADCP data following the method of Hyatt et al (2008). Daily observations from the research station at Ny Å lesund indicated that sea ice was absent from the main basin of Kongsfjorden throughout our study period.…”

Section: Methodsmentioning

confidence: 99%

Comparison of zooplankton vertical migration in an ice-free and a seasonally ice-covered Arctic fjord: An insight into the influence of sea ice cover on zooplankton behavior

Wallace

Cottier

Berge³

et al. 2010

Limnol. Oceangr.

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We present observations of zooplankton diel vertical migration (DVM) over a period of 2 yr in an ice-free and a seasonally ice-covered Arctic fjord. The contrasting environments permitted assessment of the influences of physical and biological factors on temporal variability in DVM patterns and a test of the hypothesis that a reduction in summer sea ice extent and thickness following climatic warming will lead to changes in DVM via the loss of a shading effect on the pelagic marine environment. Acoustic backscatter and vertical velocity data from moored 300-kHz acoustic Doppler current profilers were used to derive DVM patterns, while measurements of sea ice and snow thickness enabled assessment of the underwater light environment and consideration of its potential to influence DVM. Pronounced differences in DVM between the sites emerged during summertime when intermittent synchronized DVM was observed at the ice-free site, whereas the ice-covered site was characterized by asynchronous behavior, thereby highlighting the influence of sea ice. Notably, the 0.8-m-thick sea ice cover was deemed important for its influence on water column properties such as food, turbidity, and zooplankton species composition, as indicated by biological samples from moored sediment traps, rather than a simple shading of the ocean and direct modification of zooplankton DVM. Loss of Arctic sea ice is likely to have an indirect but substantial effect on zooplankton DVM via modification of hydrography and composition of the pelagic community.

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“…9) show events, such as the one of 15-29 May, when near surface layer currents dropped down to zero, probably because of sea-ice formation. It is well known that ADCP measurements are sensitive to the presence of sea ice, so that some authors suggested an alternative use of ADCP, mainly based on the analysis of echo intensity, for sea-ice draft and coverage estimation (Visbeck & Fisher 1995, Shcherbina et al 2005, Hyatt et al 2008. The dropping current events were associated with lower wind speeds, low air temperature and an increase in sea-ice concentration.…”

Section: Time Series Of Temperature and Salinitymentioning

confidence: 99%

Upper ocean layer dynamics and response to atmospheric forcing in the Terra Nova Bay polynya, Antarctica

2010

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Abstract:A one-year time series of Acoustic Doppler Current Profiler (ADCP) data was collected in Terra Nova Bay (TNB) polynya (Ross Sea, Antarctica) during 2000. Together with Automatic Weather Station (AWS) Eneide meteorological data and Special Sensor Microwave Imager (SSM/I) ice concentration data, ADCP data were analysed to investigate upper layer dynamics and variability due to atmospheric forcing. Empirical Orthogonal Function (EOF) analysis was performed to separate the surface variability caused by local forcing from the large-scale circulation component. In particular, the first mode represented the barotropic circulation while the second the stronger surface currents. The decrease in shelf water density from melting sea ice resulted in an off-shore density gradient producing a southern shift in the circulation. This result proved to be consistent with the in situ data acquired during February-April at 120 m depth. The observed variability of the surface currents was assessed with respect to the thermal wind equation and the steady Ekman model. Strong katabatic winds shifted the surface currents eastward with respect to the general north-eastern circulation. The wind stress acted as a relevant forcing for the surface large-scale circulation in TNB, but had negligible effects on the vertically integrated transport.

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Estimating sea-ice coverage, draft, and velocity in Marguerite Bay (Antarctica) using a subsurface moored upward-looking acoustic Doppler current profiler (ADCP)

Cited by 19 publications

References 17 publications

Cross‐shelf transport of warm and saline water in response to sea ice drift on the Laptev Sea shelf

Cross‐shelf transport of warm and saline water in response to sea ice drift on the Laptev Sea shelf

Comparison of zooplankton vertical migration in an ice-free and a seasonally ice-covered Arctic fjord: An insight into the influence of sea ice cover on zooplankton behavior

Upper ocean layer dynamics and response to atmospheric forcing in the Terra Nova Bay polynya, Antarctica

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