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The article focuses on the velocity field of Brunt Ice Shelf and Stancomb-Wills Ice Tongue in East Antarctica. It notes that the velocity is developed using the automated feature-tracking techniques on RADASTAT-1 imagery from the 1997 Antarctica Mapping Mission-1 (AMM-1) and 2000 Modified Antarctic Mapping Mission (MAMM). The velocity field and radar images investigation shows divergence of contemporary flowlines from relict flow stripes along a portion of Stacomb-Wills Ice Tongue. The velocity field was used in reconstructing the former stripe configuration.

Ice cores were sampled at four stations in McMurdo Sound (Ross Sea) between 1999 and 2003. At the beginning of year 2000, a very large iceberg (B-15) detached itself from the Ross Ice Shelf and stranded at the entrance of the Sound, preventing the usual oceanic circulation purging of the annual sea ice cover from this area. Ice textural studies showed that a second year sea ice cover was built-up at three out of the four stations: ice thickness increased to about 3 m. Repeated alternation of columnar and platelet ice appeared, and bulk salinity showed a strong decrease, principally in the upper part of the ice sheet, with associated brine volume decrease. Physical modification influenced the biology as well. By decreasing the light and space available for organisms in the sea ice cover, the stranding of B-15 has i) hampered autotrophic productivity, with chlorophyll a concentration and algae biomass significantly lower for second year ice stations, and ii) affected trophic relationships such as the bacterial biomass/chl a concentration correlation, or the autotrophic to heterotrophic ratio. [ABSTRACT FROM AUTHOR]

Video transects in the eastern Weddell Sea were used to classify the mega-epibenthos into stages of recolonisation after iceberg impact and unaffected fauna. Three site categories differing in bottom topography and concentration of grounded icebergs were analysed. At small iceberg banks and on a comparatively plain seabed, 52–60% of undisturbed seafloor was found, and below 20% at a large iceberg bank. The impact was calculated as a function of values for recently disturbed areas and an estimated recovery time. The results show that, statistically, the Antarctic benthos never reaches peak maturity and that iceberg scouring is among the five most significant disturbances that any large ecosystem on earth experiences. [ABSTRACT FROM AUTHOR]

Results of an analysis of the distribution and movement of extratropical cyclones around Antarctica for the period September, 1973, through May, 1975, are presented. Variations in seasonal cyclone frequencies, their preferred longitudinal positions, and the spatial and temporal fluctuations in latitude and pressure are shown, and these indicate good agreement temporal fluctuations in latitude and pressure are shown, and these indicate good agreement with the known features of Southern Hemisphere climatology. The greatest numbers of cyclones occur during spring and fall, and their most common locations are near coastal embayments. A semiannual oscillation is present in the frequencies, mean latitudes, and mean pressures of the cyclones, although to varying degrees. Longitudinal variations in the intensity of the oscillation are also evident. The belt of maximum cyclone activity exhibits a distinct half-yearly cycle in latitudinal position, although the trough is located some 5° north of the position determined from mean monthly pressures. Harmonic analysis of the spatial variation of this belt and the simultaneous position of the sea-ice margin derived from microwave imagery suggests that there is little correlation between sea ice and cyclone tracks on a hemispheric scale. Close relationships are apparent for short time periods or in specific regions but will require more intensive study before causal mechanisms can be suggested. The asymmetry of the continent, rather than the extent of sea ice, is probably the principal factor involved in determining the longitudinal variations in the positions and tracks of cyclones around Antarctica on a hemispheric scale. [ABSTRACT FROM AUTHOR]