During the SWEDARP cruise to the Atlantic sector of the Southern Ocean 1997/1998 six 24-hour stations were occupied in the areas of the Spring Ice Edge (SIE1, SIE2 and SIE3), the Winter Ice Edge (WIE), and the Antarctic Polar Front (APF1 and APF2). Samples were taken at the surface (2 m) every second hour and analyzed for total dissolved inorganic carbon, total alkalinity, pH and dissolved oxygen. By the use of wind speed measurements, calculated fugacity of carbon dioxide, fCO(2), and oxygen concentrations in the surface water, sea-air fluxes of carbon dioxide (CO2) and oxygen were calculated. These fluxes and the diurnal change in the chemical properties are discussed in relation to changes in biological activity. The fluctuations in wind speed showed a larger impact on the variability of the calculated fluxes than the fluctuations in surface water fCO(2) or oxygen saturation. The calculated fluxes and the variability also showed large differences depending on how the wind speed was used, instantaneously or averaged over 24 hours. The calculated sea-air CO2 fluxes using instantaneous wind speed varied between -0.012 and -0.11 mmol m(-2) h(-1) in the SIE1, -0.0073 and -0.30 mmol m(-2) h(-1) in the WIE and -0.043 and -1.65 mmol m(-2) h(-1) in the APF2. The mean values of sea-air CO2 fluxes were calculated to -0.046+/-0.044, -0.10+/-0.094 and -0.52+/-0.64 mmol m(-2) h(-1) for the SIE1, WIE and the APF2, respectively. The mean values of sea-air oxygen fluxes were calculated to 0.072+/-0.073, -0.12+/-0.54 and 1.4+/-1.3 mmol m(-2) h(-1) for the corresponding regions. (C) 2004 Elsevier Ltd. All rights reserved.

The glaciers that drain the West Antarctic Ice Sheet into the Amundsen Sea are accelerating and experiencing increased basal melt of the floating ice shelves. Warm and salty deep water has been observed to flow southward in deep troughs leading from the shelf break to the inner shelf area where the glaciers terminate. It has been suggested that the melting induced by this warm water is responsible for the acceleration of the glaciers. Here we investigate the structure of the currents and the associated heat flow on the shelf using in-situ observations from 2008 to 2014 in Dotson Trough, the main channel in the western part of the Amundsen Sea shelf, together with output from a numerical model. The model is generally able to reproduce the observed velocities and temperatures in the trough, albeit with a thicker warm bottom layer. In the absence of measurements of sea surface height we define the barotropic component of the flow as the vertical average of the velocity. It is shown that the flow is dominated by warm barotropic inflows on the eastern side and colder and fresher barotropic outflows on the western side. The transport of heat appears to be primarily induced by this clockwise barotropic circulation in the trough, contrary to earlier studies emphasizing a bottom-intensified baroclinic inflow as the main contributor. (C) 2015 Elsevier Ltd. All rights reserved.