Observations of unusual fast-ice conditions in the southwest Ross Sea, Antarctica: preliminary analysis of iceberg and storminess effects

Abstract

AbstractMassive tabular icebergs (∽1000km2surface area, ∽1011 kg mass) arrived in the southwest Ross Sea in early 2001 where they remained relatively immobile for the next 4 years. During the period of their presence, extensive landfast sea ice (fast ice) waxed and waned along the Victoria Land coast, with maximum coverage exceeding typical coverage prior to the arrival of the icebergs by a factor of 5. The purposes of this study are to determine (1) whether the extensive ‘iceberg blockade’ extending from Ross Island to Drygalski Ice Tongue was indeed, as intuition suggests, responsible for the unusual fast-ice conditions, and (2) how storm frequency, intensity and seasonal timing may have mitigated the effects of the icebergs. Our simple analysis of glaciological and atmospheric conditions observed during 2001–05 suggests that iceberg movement alone is not sufficient to explain fast-ice variability; and, in fact, it is the detailed interplay between storms and iceberg location that determine this variability.