Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Victoria University Antarctic Research Expedition Science and Logistics Reports 1981-82: VUWAE 26

McMurdo Sound Bathymetry and Oceanography (K5)- P. Barrett

page 10

McMurdo Sound Bathymetry and Oceanography (K5)- P. Barrett.

Over the last four seasons about 200 soundings have been made from surveyed positions on the sea ice in the course of gravity survey (Sissons, 1980) and sediment sampling (Barrett, 1979; Pyne, 1981; and this season). Most measurements were made with a weighted terylene line, and compare well with measurements from a meter wheel on 5mm steel cable taken during coring, the terylene gave measurements from 0 to 3m greater than the steel cable along the western side of the Sound and in Granite Harbour in depths as gerat as 550m, though in the central part of the Sound, where there may have been significant current activity measurements ranged from 0 to 16m greater.

Bathymetry beyond the coastal fringe was obtained from continuous depth recorder records off cruises by VUW and DSIR personnel since 1972 and plotted by B. Ward. The ships track was obtained from satellite navigation data, radar fixes and dead reckoning, and depths were read off at km intervals. Most depths at track crossings were within 10m, the greatest different being 24m. Comparison of depths from ships tracks and line soundings are hard to make because of errors in the ships position of several hundred metres, and local relief of the sea floor, but appear to be of the order of a few metres. 500 data points were plotted from the shipboard data, and contoured along with the nearshore data (Fig. 7). Soundings were also made in Granite Harbour, allowing for the first time a coherent view of its bathymetry (Fig. 6).

Measurements of current velocity and tide were made over a 2 day period in 167m of water 0.6km off the edge of the Strand Moraines (77°45S; 164°30E). Velocities ranged from less than 0.02 (sensitivity of the meter) to 0.12m/s, but appeared unrelated to the phase of the tide, which had a range of 0.6m in that period. No current was recorded near the sea floor but became detectable about 5m above. Flow was invariably to the north, judging from the deflection of the wire.

page break
Figure 6 (above) & 7 (below): Bathymetry of McMurdo Sound and New Harbour respectively. Locations of cores 1 to 18 are also shown.

Figure 6 (above) & 7 (below): Bathymetry of McMurdo Sound and New Harbour respectively. Locations of cores 1 to 18 are also shown.