Remembering Tore Gjelsvik (1916–2006)

Tore Gjelsvik, former director of the Norwegian Polar Institute, died at the beginning of this year. He is fondly remembered by a great many people. In this piece, Olav Orheim recalls the man and his key role in Norwegian polar activities. Orheim was head of Antarctic Research at the Norwegian Polar Institute in 1972–1993 and was the institute’s director from 1993 to 2005

A 200-Year Record of Glacier Mass Balance at Deception Island, Southwest Atlantic Ocean, and Its Bearing on Models of Global Climatic Change

"RF-3231-A1."Subglacial volcanic eruptions on Deception Island (63°S, 60°40'W) in 1969 and 1970 revealed ice stratigraphy in fissures and craters. Annual net mass-balance variations from about 1780 A.D. to the present were determined from this stratigraphy. Annual layers were exceptionally well marked by dirt layers, formed each summer when large amounts of dust are blown onto the glaciers from surrounding areas of loose volcanic material. No dust is deposited on the glaciers in the winter because the island is then completely snow-covered. The sections studied originated high in the accumulation area of the glacier, and only minor errors in the record are caused by years missed due to zero or negative net balance. Meteorological data are available from Deception Island from 1944 to 1967; summer degree-days for these years are significantly negatively correlated with stratigraphically determined net mass balances (r= -0.55, P < 0.01). This correlation generally becomes insignificant when dating of the layers is changed by one or more years and thus provides a confirmation of the stratigraphic technique. The correlation also shows that summer degree-days and summer balances must be closely correlated; year-to-year variations in the summer balances, as represented by the summer degree-days, account for a larger proportion of annual net balance variations than do winter balance variations. Close correlation between summer degree-days and summer balances is supported by heat- and mass-balance results on a selected glacier on the island. This glacier was in mass equilibrium for the 1968-1969 balance year but had negative mass balances for the following two years. Shortwave solar radiation contributed most of the heat transfer to the glacier in the summer. Mean gradients with respect to elevation of the summer, winter, and net balance curves are 6, 1, and 7 mm m-1, respectively. The term "mean activity index" is proposed for the latter gradient, and its use is suggested in place of Shumskii's "energy of glacierization" and Meier's "activity index." The stratigraphic studies revealed 23 probable volcanic eruptions since 1780. Although these eruptions have changed significantly the mass and heat balance conditions in the ablation area of the glaciers, their effects were not significant in the accumulation areas, where the ash is buried within a year. Comparisons between summer temperatures at Deception Island and those of 14 other stations in middle to high latitudes in the southern hemisphere show that summer temperature variations at Deception Island are representative of regional variations in the southwest Atlantic Ocean. Mean mass balances for 5-year intervals, and 5-year running means of balances for Deception Island are significantly negatively correlated with observed mass-balance variations from 1946 in the northern hemisphere, and balances in both hemispheres show a marked cyclicity of about 10 years. The same antiphase relationship, with a cycle of 11 years, and a weaker cycle of about 20 years, is found when the entire Deception record is compared with the precise record back to l8l6 from Storbreen, Norway. The entire Deception Island record shows the same general atmospheric warming from the 19th to the present century, as occurred in the northern hemisphere and in lower to middle latitudes of the southern hemisphere. Models proposed to explain climatic changes must account for a global warming from late last century to about 1940, and an antiphase cyclic relationship, characterized by dominant periods of about 11 and about 20 years, in the climatic elements that affect glacier mass balances in middle to high latitudes in the two hemispheres.National Science Foundation Grants GA-4233, GA-14733, GV-26133 and GV-28895

Quantifying dissolution rates of Antarctic icebergs in open water

At any one time 130 000 icebergs are afloat in the Southern Ocean; 97% of these are too small to be registered in current satellite-based databases, yet the melting of these small icebergs provides a major input to the Southern Ocean. We use a unique set of visual size observations of 53 000 icebergs in the South Atlantic Ocean, the SCAR International Iceberg Database, to derive average iceberg dissolution rates. Fracture into two parts is the dominant dissolution process for tabular icebergs, with an average half-life of 30 days for icebergs <4 km length and 60 days for larger icebergs. Complete shatter producing many icebergs <1 km length is rare. A side attrition rate of 0.23 m d−1 combined with drift speed of 6 km d−1, or any proportional change in both numbers fits the observed changes in iceberg distribution. The largest injection into the Southern Ocean of fresh water and any iceberg-transported material takes place in a ~2.3 × 10⁶ km2 zone extending east-northeast from the Antarctic Peninsula to the Greenwich meridian. The iceberg contribution to salinities and temperatures, with maximum contribution north of the Weddell Sea, differs in some regions, from those indicated by tracking large icebergs

A Framework for the International Polar Year, 2007-2008

The polar regions are integral components of the Earth system. As the heat sinks of the climate system they both respond to and drive changes elsewhere on the planet. Within them lie frontiers of knowledge as well as unique vantage points for science. Yet because of their remoteness and harsh nature, the poles remain insufficiently studied. With recent technological advances providing new scientific possibilities, and humankind‘s need for environmental knowledge and understanding ever increasing, the time is ripe for a coordinated international initiative to achieve a major advance in polar science. For this reason, the International Council for Science (ICSU) decided to take the lead in organizing an International Polar Year (IPY) in 2007-2008. They did so by establishing an IPY Planning Group (PG) charged with developing the IPY 2007-2008 science plan and implementation strategy. This report is the outcome of the PG‘s work. It is based on input from individuals, from over 40 governmental and nongovernmental organizations that have endorsed or expressed support for IPY 2007-2008, and from the 32 IPY National Committees or National Points of Contact established so far. It is also results from discussions and debate at over a dozen international meetings covering the gamut of science disciplines, from a series of "town" meetings, and from two Discussion Forums hosted by ICSU and attended by representatives of the IPY National Committees and a variety of interested polar organizations

Review of Climate change in the polar regions, by John Turner & Gareth J. Marshall

In this ambitious, cross-disciplinary volume, British Antarctic Survey scientists John Turner and Gareth Marshall synthesize what is known about climate change in the Arctic and Antarctic and compare the changes that have occurred in the two polar regions. The authors examine recent changes in light of those that have taken place over the course of the last million years, and tackle the difficulties involved in teasing apart natural from anthropogenic change. The book is arranged in eight sections: an introduction; polar climate data and models; high-latitude climates and mechanisms of change; the last million years; the Holocene; the instrumental period; predictions for the next 100 years; and a summary.(Published: 12 March 2012)Citation: Polar Research 2012, 31, 17512, DOI: 10.3402/polar.v31i0.1751

Review of Antarctic climate change and the environment edited by John Turner et al.

This impressive report from the Scientific Committee on Antarctic Research (SCAR) covers nearly 400 pages of text with more than 100 additional pages of references. Under the clearly very able leadership of John Turner of the British Antarctic Survey, the nine editors have coordinated more than 100 contributors to produce a comprehensive review of our knowledge of Antarctica&rsquo;s climate up to 2007. (Published: 21 February 2011) Citation: Polar Research 2011, 30, 5985, DOI: 10.3402/polar.v30i0.598