On the use of stable isotopes to trace the origins of ice in a floating ice tongue

Stable isotope analysis has been used successfully to distinguish between several different ice types in an ice tongue floating on sea water in Antarctica. At one critical location this technique has provided the only means of discriminating unambiguously between glacial ice and fresh-water ice formed from desalinated sea water. This part of the ice tongue is now underlain by a layer of desalted sea water thick enough to prevent any further accretion of sea ice at this location

Some Characteristics of Grounded Floebergs near Prudhoe Bay, Alaska

During the winter of 1974-75, a large number of floebergs (fragments of multi-year pressure ridges) were found incorporated in the fast ice northwest of Prudhoe Bay, Alaska. Many of them had been driven up onto the sea floor and become stranded, as was indicated by their high free-board. ... In order to gather information on the shape and structure of floebergs, and their effect upon the sea bed during groundings, studies were undertaken in April 1975 in the area located approximately 35 km northwest of Prudhoe Bay (70 35 N, 148 50 W). These studies included the determination of the surface relief of two floebergs (henceforward designated A and B) by means of standard surveying techniques; snow thickness measurements; the profiling of the floeberg keels by a sonar technique developed by Kovacs, and an examination of the internal structures of the floebergs, including voids and impurities, as observed in fracture faces on their sails and the portions of their keels uplifted upon grounding. The fast ice surface in the immediate area of the floebergs was highly irregular, due largely to the incorporation of ice fragments into the ice sheet. The surface was covered with a layer of snow that varied in thickness from 10 to 40 cm, depending on the relief of ice

Physical and structural characteristics of Weddell Sea pack ice

Journal ArticleRecent studies by CRREL researchers of the dynamics and thermodynamics of sea ice in the Antarctic have included investigations of the physical and structural properties of pack ice in the Weddell Sea. The formation of pack ice and its subsequent movement from source areas in the Weddell Sea is particularly important in modifying ocean-atmosphere and water mass development both in and beyond the Weddell Sea embayment. The pack ice area affected by Weddell Sea processes is 8-10 million square kilometers (Ackley 1979a), thus representing about one - third of the total area os sea ice encircling Antarctica at its maximum extent

Six-year record of oxygen and hydrogen isotope variations in South Pole firn

Direct measurements of snow accumulation at stakes near the South Pole over a 6-year period (1958–1963) provide an unusual opportunity to check the reliability of accumulation and annual-layer determinations by stratigraphic and isotopic methods. The results are gratifying. Agreement between interpretations based on stratigraphic and isotopic data is excellent, and both are consistent with accumulation-stake measurements in nearly all respects. All three procedures indicate an average annual accumulation of 7 cm of water at the South Pole over the 1958–1963 interval. Isotope data suggest that depth-hoar formation may result in relative enrichment in O^(18). This could come about through partial recondensation of vapor generated within the depth-hoar layer accompanied by escape of residual vapor impoverished in O^(18)

Accumulation at South Pole: Comparison of two 900-year records

This is the published version, also available here: http://dx.doi.org/10.1029/1999JD900501.Two 900-year records of annual accumulation at South Pole are compared to evaluate the origin and significance of observed variations. Despite difficulties establishing absolute timescales, due to problems identifying annual layer markers, the two records can be correlated with confidence after moderate smoothing. This correlation shows that over the time period considered (1050–1956 A.D.) no climatically significant changes in accumulation occurred. Instead, fluctuations preserved in the two cores reflect spatial variations in snow accumulation, associated with nonuniform deposition induced by surface relief on the scale of several kilometers

The Dominion Range Ice Core, Queen Maud Mountains, Antarctica - General Site and Core Characteristics with Implications

The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including ice surface, ice thickness, bore-hole temperature, mean annual net accumulation, crystal size, crystal fabric, oxygen-isotope composition, and examples of ice chemistry and isotopic composition of trapped gases

The Dominion Range Ice Core, Queen Maud Montains, Antarctica - General Site and Core Characteristics with Implications

The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including ice surface, ice thickness, bore-hole temperature, mean annual net accumulation, crystal size, crystal fabric, oxygen-isotope composition, and examples of ice chemistry and isotopic composition of trapped gases

The Dominion Range Ice Core, Queen Maud Mountains, Antarctica—General Site and Core Characteristics with Implications

The Transantarctic Mountains of East Antarctica provide a new milieu for retrieval of ice-core records. We report here on the initial findings from the first of these records, the Dominion Range ice-core record. Sites such as the Dominion Range are valuable for the recovery of records detailing climate change, volcanic activity, and changes in the chemistry of the atmosphere. The unique geographic location of this site and a relatively low accumulation rate combine to provide a relatively long record of change for this potentially sensitive climatic region. As such, information concerning the site and general core characteristics are presented, including ice surface, ice thickness, bore-hole temperature, mean annual net accumulation, crystal size, crystal fabric, oxygen-isotope composition, and examples of ice chemistry and isotopic composition of trapped gases

Electromagnetic and physical properties of sea ice formed in the presence of wave action

Estimating the magnitude of brine flux to the upper ocean requires an ability to assess the dynamics of the formation of sea ice in a region. Brine storage and rate of expulsion is determined by the environmental conditions under which the sea ice forms. In this paper, the physical and electromagnetic properties of sea ice, formed under wave-agitated conditions, are studied and compared with results obtained from ice formed under quiescent conditions. Wave agitation is known to have a profound effect on the air-ice interface and internal ice structure. A variety of sensors, both active and passive, optical and microwave, were used to perform this characterization. Measured electromagnetic parameters included radar backscatter, microwave emission, and spectral albedo in the visible and infrared. Measured physical properties included ice structure, brine and temperature distribution, profiles of the vertical height of the air-ice interface, and ice formation processes. Results showed that emission, backscatter, and albedo all take different signature paths during the transformation from saline water to young sea ice and that the paths depend on sea surface state during ice formation