The International Trans-Arctic Scientific Expedition (ITASE): An Overview

From its original formulation in 1990 the International Trans-Antarctic Scientific Expedition (ITASE) has had as its primary aim the collection and interpretation of a continent-wide array of environmental parameters assembled through the coordinated efforts of scientists from several nations. ITASE offers the ground-based opportunities of traditional-style traverse travel coupled with the modern technology of GPS, crevasse detecting radar, satellite communications and multidisciplinary research. By operating predominantly in the mode of an oversnow traverse, ITASE offers scientists the opportunity to experience the dynamic range of the Antarctic environment. ITASE also offers an important interactive venue for research similar to that afforded by oceanographic research vessels and large polar field camps, without the cost of the former or the lack of mobility of the latter. More importantly, the combination of disciplines represented by ITASE provides a unique, multidimensional (space and time) view of the ice sheet and its history. ITASE has now collected \u3e20 000km of snow radar, recovered more than 240 firn/ice cores (total length 7000 m), remotely penetrated to ~4000m into the ice sheet, and sampled the atmosphere to heights of \u3e20 km

The Stress Pattern within the Law Dome Summit to Cape Folger Ice Flow Line, Inferred from Measurements of Crystal Fabric

Crystal fabric and texture data are presented from ten ice cores that have previously been drilled along an approximate flow line extending from the summit of Law Dome ice cap to Cape Folger, East Antarctica. Our interest in these data is their interpretation in terms of stress patterns within the ice cap, and in particular the detection of the depths at which the stress changes from predominantly near-vertical compression to predominantly near-horizontal simple shear zones. This transition potentially marks an increase in flow rate, from a factor of ～3 in the compression zone to ～10 in the shear zone, compared to deformation of the initially isotropic ice that accumulates at the surface. Determining the depth of this potentially large change in flow rate between compression flow and shear flow provides valuable information for computer models of the ice sheet. In the Law Dome ice cap the compression-shear transition is found at approximately one-third of the total depth.I. Microphysical properties, deformation, texture and grain growt

Flow rates and crystal orientation fabrics in compression of polycrystalline ice at low temperatures and stresses

International Symposium on Physics of Ice Core Records. Shikotsukohan, Hokkaido, Japan, September 14-17, 1998

Antarctic iceberg distribution and dissolution from ship-based observations

ABSTRACT. The Australian Antarctic Program’s iceberg dataset (from ship-based observations), including information from the austral summer seasons 1984/85 to 1999/2000, is examined and used to extend earlier studies. Using ‘snapshots ’ of the iceberg population to provide an idea of the iceberg life cycle, the distribution of icebergs between 60 and 1508 E is discussed in terms of calving regions and ocean currents. Temporal changes are also examined. The discussion leads us to the point where we can define an area, bounded to the north by the maximum sea-ice limit and to the south by the Antarctic Divergence, in which icebergs are confined as they drift eastward. This allows estimation of total dissolution, in terms of iceberg numbers and volume, within 108 longitudinal sectors and, with knowledge of drift speeds, iceberg movement rates and freshwater input across the sector. Iceberg dissolution rates are found to be �0.03–0.05 m d –1 and the total mass contribution of fresh water to the ocean as the icebergs traverse our 308 of longitude study sector is �32 Gt. This amounts to a contribution equivalent to precipitation of �15.5 cm a –1, accounting for �2 % of the total iceberg discharge from the Antarctic ice sheet