Found 13653 items
1 January, 1998 by Richard Horne
The possibility of electron stochastic energization to relativisitic energies (≥ 1 MeV) via resonant wave-particle interactions during a magnetic storm is explored. The minimum electron energy Emin for cyclotron resonant…1 January, 1998 by John King
Atmospheric wave-trains of climate anomalies are investigated as a candidate for linking low and high latitude atmospheric signals during Pacific Ocean warm (ENSO) and cold (La Niña) events. Study results,…1 January, 1998
An area of mudwave development has been identified from the northwestern Powell Basin, northern Weddell Sea, Antarctica. The wave-field is located near the base of the continental slope in water…1 January, 1998
F region peak heights, derived from ionospheric scaled parameters through 38-year data series from both Argentine Islands (65°S, 64°W) and Port Stanley (52°S, 58°W) have been analyzed for signatures of…1 January, 1998
The implementation of a technique to derive mesospheric winds from HF radar observations of meteor echoes at Halley (76°S, 27°W), Antarctica, is described. The meteor echoes are observed at near…1 January, 1998 by Anna Jones, John Turner
A regular occurrence during the 1990s has been the excursion of the edge of the springtime Antarctic ozone hole over the southernmost region of the South American continent. Given the…1 January, 1998
Observations of satellite passes monitored at Halley and Terra Nova Bay have been combined to produce for the first time measurements of ionospheric electron content spanning the Antarctic continent. Results…Read more on Ionospheric electron content across the Antarctic continent
1 January, 1998
The dynasonde at Halley, Antarctica, is operated throughout the year making ionogram soundings every five minutes. The extensive database of observations from 1993 and 1994 has been processed to investigate…1 January, 1998
Since 1959 the British Antarctic Survey (BAS) has undertaken reconnaissance gravity surveys of the Antarctic Peninsula. Approximately 1500 on-rock and about 600 on-snow station values were measured. Continuing climatic, topographical…Read more on Towards a new free air anomaly map of the Antarctic Peninsula
1 January, 1998
New constraints on the age of the Cockburn Island Formation, northern Antarctic Peninsula, resulting from whole rock laser-stepped heated 40Ar–39Ar dating of associated basalt and palaeomagnetic re-calibration of the ranges…1 January, 1998
The longest-known pectinid-bearing deposit in the Antarctic, the "Pecten-conglomerate" of Cockburn Island in the James Ross Island group, northern Antarctic Peninsula, is herein formally named the Cockburn Island Formation. A…1 January, 1998
Antarctic late Cenozoic pectinid-bearing sedimentary strata are chiefly confined to localities in the northern part of the Antarctic Peninsula, in the McMurdo Sound area, and Marine Plain, East Antarctica. Ages…Read more on Stratigraphy of Antarctic late Cenozoic pectinid-bearing deposits
1 January, 1998
Macrofossil content from the Miocene part of CRP-1 core, Cape Roberts (Victoria Land Basin) is scant and mostly limited to a few pectinid bivalves and serpulid polychaetes. Selective diagenesis has…1 January, 1998
Levels of persistent organic pollutants (POPs), such as polychlorinated biphenyls and pesticides have been determined in ambient air at Signy Island, Antarctica, over a period of 17 weeks. Mean concentrations…1 January, 1998 by John King, Thomas Lachlan-Cope
We use snow surface temperatures obtained from thermal infrared (TIR) satellite imagery, together with radiosonde profiles of free-air temperature and high-resolution topographic data to study the thermal structure of the…1 January, 1998 by John King
Temperature records from stations on the west coast of the Antarctic Peninsula show a very high level of interannual variability and, over the last 50 years, larger warming trends than…1 January, 1998 by Andrew Clarke
The temperature of the Southern Ocean has undergone an overall reduction from about 20 °C to −1.8 °C over the last 55–60 million years. To date, the Southern Ocean is…Read more on Age, growth and maximum size of Antarctic notothenioid fish — revisited
1 January, 1998 by John King
Long term air and snowfall chemistry measurements have been performed at the three coastal Antarctic stations Dumont d'Urville (66°40′S, 140°1′E), Neumayer (70°39′S, 8°15′W), and Halley (75°35′S, 26°19′W). The results have…1 January, 1998 by Ed King, Philip Leat, Robert Larter
The simple tectonic history of the South Sandwich island arc, a classic intra-oceanic arc lying in the South Atlantic Ocean, provided excellent opportunities for the Sandwich Lithospheric and Crustal Experiment…Read more on South Sandwich slices reveal much about arc structure, geodynamics, and composition
1 January, 1998
Strontium isotope stratigraphy was used to date five discrete horizons within CRP- 1. Early and late Quaternary (0 87- 1 3 Ma and 0-0 67 Ma respectively) age sediments overlie…Read more on Strontium-isotope stratigraphy of the CRP-1 drillhole, Ross Sea, Antarctica
1 January, 1998 by Robert Mulvaney
Year-round aerosol samples collected in the boundary layer at coastal Antarctic sites (Dumont D'Urville, Neumayer, and Halley) indicate a seasonal cycle of ammonium concentrations with a minimum in winter (April–September).…1 January, 1998
Multiple-year time series of the weight ratio R of methane sulfonic acid (MSA) to non-sea-salt sulfate (nss SO4) in aerosols collected at three coastal Antarctic stations Neumayer (70°39′S, 8°15′W), Halley…1 January, 1998 by Michael Pinnock
The Finnish radar of CUTLASS has been operational since February 1995. Between 0620 and 0800 UT on August 25 1995, a region of ionospheric scatter, which was limited to only…Read more on CUTLASS observations of convection in the cusp region
1 January, 1998 by Mervyn Freeman
We use the Goose Bay HF radar to investigate the behavior of the electric field within the substorm current wedge for a small substorm (< 200 nT) which occurred on…Read more on The behavior of the electric field within the substorm current wedge
1 January, 1998
An extended interval of strong northward interplanetary magnetic field (IMF) was observed by the Wind spacecraft located at an upstream distance of ∼193 RE from February 8–10, 1995, with a…Read more on Multipoint study of a substorm on February 9, 1995
1 January, 1998 by Philip Leat
The isotopic difference between modern Indian Ocean and Pacific or North Atlantic Ocean ridge mantle (e.g. variably lower 206Pb/204Pb for a given εNd and 208Pb/204Pb) could reflect processes that occurred…1 January, 1998 by Gareth Marshall, John King
The Southern Hemisphere reveals markedly different circulation patterns associated with extreme warm and cold Antarctic Peninsula (AP) winter temperatures. Warm winters are associated with negative 500 hPa height anomalies in…1 January, 1998 by Gareth Marshall, John Turner
In this study we correlate temporal features within the electrical conductivity (acidity) traces of four shallow firn cores obtained from the southern Antarctic Peninsula to synoptic-scale variations in the regional…1 January, 1998
Aerobiological sampling was conducted year-round at three sites on Signy Island, maritime Antarctic, between December 1992 and January 1994, and during the summer at a fourth coastal site. The concentrations…1 January, 1998
Anterior eye structure and retinal visual fields were determined in grey–headed and black–browed albatrosses, Diomedea melanophris and D. chrysostoma (Procellariiformes, Diomedeidae), using keratometry and an ophthalmoscopic reflex technique. Results for…Read more on Eye structure and amphibious foraging in albatrosses
1 January, 1998
The diving behaviour of Antarctic fur seal (Arctocephalus gazella) pups on Bird Island, South Georgia (54°S, 38°W), was examined during February-April 1996 using capillary-tube depth gauges (CDGs) and time-depth recorders…Read more on Diving behaviour of Antarctic fur seal (Arctocephalus gazella) pups
1 January, 1998
This study examined the relative contribution of environmental variation and the seasonal demands of pup rearing on the foraging behaviour of female Antarctic fur seals Arctocephalus gazella at Bird Island,…Read more on Foraging responses of Antarctic fur seals to changes in the marine environment
1 January, 1998
Alexander Island, situated off the west coast of the Antarctic Peninsula, contains a suite of Late Cretaceous to Early Tertiary subduction-related magmatic rocks. The rocks occupy a fore-arc position 100–200…1 January, 1998 by Robert Larter
Quantitative estimates of the rates and azimuths of Phoenix plate convergence with the Antarctic Peninsula have been derived from plate rotation calculations for two periods in the Late Cretaceous and…Read more on Late Cretaceous to early Tertiary subduction history of the Antarctic Peninsula
1 January, 1998 by Sandra McInnes, Sandra McInnes
The Tardigrada is a cosmopolitan phylum of pre-Pangaean origin, yet tardigrade families and genera show distinct biogeographic components isolated by two major geological events. Separate Laurasian and Gondwanan familial clusters…1 January, 1998 by Thomas Lachlan-Cope
The British Antarctic Survey operates both aircraft and ships in the Antarctic. High quality weather forecasts can have a large impact on safe operations at high southern latitudes. This paper…1 January, 1998 by Lloyd Peck
The reproductive cycle of the Antarctic articulate brachiopod Liothyrella uva (Broderip, 1833) is described from monthly samples collected between September 1985 and July 1987 from a population at Signy Island,…Read more on Reproductive patterns in the Antarctic brachiopod Liothyrella uva
1 January, 1998 by Eric Wolff
The concentrations of sulfur-containing species (sulfate and methanesulfonate (MSA)) of aerosols collected at three coastal Antarctic sites (Neumayer, Dumont d'Urville, and Halley) have been studied in order to investigate the…1 January, 1998
We report recent mapping of Spiess Ridge with the Hawaii-MR1 sidescan sonar. Spiess Ridge is an unusual elongate 90 by 50 km volcanic feature on the slow spreading Southwest Indian…Read more on Spiess Ridge: An axial high on the slow spreading Southwest Indian Ridge
1 January, 1998
New Hawaii-MR1 sonar data show that the southernmost Mid-Atlantic Ridge joins the South American–Antarctic Ridge by an obliquely opening rift and overlaps Spiess Ridge, the westernmost segment of the Southwest…Read more on The present configuration of the Bouvet triple junction
1 January, 1998
The existence of seasonal changes in concentrations of water-soluble carbohydrates in arthropods (both freezing-tolerant and intolerant species) from Signy Island was demonstrated. Seasonal patterns of variation, imposed by seasonality of…1 January, 1998
Quaternary deposits in six sediment cores from the Scotia Sea, Antarctica, were examined for the presence of volcanic ash layers. The cores were recovered from water depths of 3369-4025 m.…1 January, 1998 by Eric Wolff, Robert Mulvaney
Postdepositional loss of nitrate in near-surface snowfall is well known, with mean levels of nitrate in ice cores of around 20 to 80 ng g−1, while nitrate in surface snow…1 January, 1998 by Eugene Murphy
Most analyses of marine microbial systems in the seasonally ice covered areas of the Southern Ocean have been based on data from the major embayment areas of the Ross and…1 January, 1998 by Eugene Murphy, Jonathan Watkins, Philip Trathan
Interannual variability is a characteristic feature of the Southern Ocean ecosystem, yet the relative roles of biological and physical processes in generating these fluctuations are unknown. There is now extensive…1 January, 1998 by Richard Hindmarsh, Richard Hindmarsh
A linearized perturbation about a two-dimensional Vialov-Nye icesheet profile is used to investigate the sensitivity of the divide position at Siple Dome, West Antarctica, to small changes in the accumulation…Read more on Sensitivity of the divide position at Siple Dome, West Antarctica to boundary forcing
1 January, 1998 by Philip Trathan
Gobionotothen gibberifrons1 January, 1998
This paper investigates the climate change in two atmosphere-ice-ocean coupled climate models - the UKMO and the CSIRO - in the Antarctic region over the next century. The objectives were…1 January, 1998
There are five species in the genus Ditrichum Hampe in the Antarctic: D. heteromallum (Hedw.) Britt., D. conicum (Mont.) Mitt., D. austrogeorgicum (Card.) Seppelt, D. lewis-smithii Ochyra and D. gemmiferum…1 January, 1998 by Michael Pinnock
We report a case study of decameter-scale electron density irregularities associated with polar cap patches and auroral (boundary) blobs in the southern high-latitude F region ionosphere. The observations were carried…1 January, 1998
Beak shapes in nine species of Southern Ocean octopodids were measured using seven size-standardized ratios. The results were analysed using principal component analysis and discriminant function analysis and show that…1 January, 1998
In long-lived and monogamous species, with partners separated between breeding seasons, the previous mate usually returns and waiting is therefore rewarded, thus contributing to mate retention as an adaptive strategy.…Read more on Divorce in king penguins: asynchrony, expensive fat storing and ideal free mate choice
1 January, 1998
A basic background is presented for the discussion of the Early Palaeozoic geology of western Argentina covered by this book. This includes the definition and terminology of orogenic cycles on…Read more on The proto-Andean margin of Gondwana: an introduction
1 January, 1998
A new multi-disciplinary study of the central Sierras Pampeanas encompasses fieldwork, petrography, metamorphic and micro-structural analysis, geochemistry and geochronology. Remnants of a low-to-medium grade metasedimentary sequence, which also occurs in…1 January, 1998
Marie Byrd Land, Antarctica, is a major part of the proto-Pacific supercontinental margin. On the basis of new geochronological and geochemical data relating to its pre-Jurassic evolution, Marie Byrd Land…1 January, 1998 by Philip Leat, Teal Riley
The field occurrence, age, classification and geochemistry of the Mesozoic volcanic rocks of Patagonia and West Antarctica are reviewed, using published and new information. Dominated by rhyolitic ignimbrites, which form…1 January, 1998
Field and earthquake data are presented which show that small faults can be important during block rotation. `Small' here means those faults which are at least an order of magnitude…Read more on Evidence for the importance of `small’ faults on block rotation
1 January, 1998 by Helen Peat
The British Antarctic Survey's Antarctic Plant Database holds over 50,000 herbarium records for Antarctic and sub-Antarctic flowering plants and cryptogams held in herbaria world-wide. In addition, it holds information on…Read more on The Antarctic Plant Database: a specimen and literature based information system
1 January, 1998 by Lloyd Peck
The rise in metabolism following feeding exhibited by animals, known as the heat increment or specific dynamic action (SDA) of feeding has been well known since the 1930s when it…Read more on Feeding, metabolism and metabolic scope in Antarctic marine ectotherms
1 January, 1998 by Alistair Crame
Aims to describe petrography and geochemistry of calcite cements precipitated in species borings from the lower 180m of La Meseta Formation on island. Interprets data in terms of diagenetic history…1 January, 1998 by Howard Roscoe
A new method for retrieving the vertical profile of NO2 from ground-based measurements is applied to four months of measurements made at Aberdeen (57°N) during part of SESAME from November…1 January, 1998 by Eugene Murphy
In view of the wide range of estimates for the total primary production for the Southern Ocean south of the Subantarctic Front—current estimates range from 1.2 to 3.5 Gtonne C…1 January, 1998 by Eugene Murphy
The Southern Ocean is the largest of the high-nutrient, low-chlorophyll (HNLC) regions of the world ocean. Phytoplankton production fails to utilise completely the pool of inorganic nutrients in the euphotic…1 January, 1998
On the continental rise west of the Antarctic Peninsula there are nine large mounds interpreted as sediment drifts, separated by turbidity current channels. Drift 7 is 150 km long, 70…1 January, 1998
Within the Scotia Sea, the axis of the Antarctic Circumpolar Current (ACC) is geographically confined, and sediments therefore contain a record of palaeo-flow speed uncomplicated by ACC axis migration. We…Read more on Quaternary history of the Antarctic Circumpolar Current: evidence from the Scotia Sea
1 January, 1998 by Sandra McInnes, Sandra McInnes
The tardigrade faunas of six Arctic sites (Canadian Axel Heiberg I., east and west coasts of Greenland, Iceland, Svalbard, Novaya Zemlya and the Russian Taimyr Peninsula) form, with those of…Read more on The origin of Arctic terrestrial and freshwater tardigrades
1 January, 1998
From a detailed study of a 500 km transect in the Sierras Pampeanas, central-west Argentina, two pre-Silurian tectono-magmatic episodes are recognized and defined, each culminating in micro-continental collisions against the…Read more on Early evolution of the Proto-Andean margin of South America
1 January, 1998
A detailed study of the pre-Silurian geology of the Sierras de Córdoba, Eastern Sierras Pampeanas, is used to define the sequence of magmatic and metamorphic events during the Pampean orogeny.…1 January, 1998 by John King
Large amplitude, isolated, wave-like phenomena have been observed in the lowest 40 m of the strongly stably stratified atmospheric boundary layer overlying a coastal Antarctic ice shelf. The waves only…Read more on Observations of solitary waves in the stable atmospheric boundary layer
1 January, 1998
A discriminant function using simple carapace measurements corretly determined the sex of 87% of male and 89% of female Antarctic krill Euphausia superba. This facilitated the use of sex-specific regression…Read more on Determining the sex of Antarctic krill Euphausia superba using carapace measurements
1 January, 1998 by Alistair Crame
The Lagrelius Point Formation from its type area in north-west James Ross Island, Antarctica has yielded dinoflagellate cysts indicative of an earliest Aptian age. Reworked palynomorphs presumed to be from…Read more on The age of the base of the Gustav Group in the James Ross Basin, Antarctica
1 January, 1998
Historically, the term polar patch was used to describe isolated regions of enhanced 630 nm emission observed in the polar cap. In recent years, signatures from other instruments, such as…1 January, 1998
Whilst it is well-accepted that short-duration changes to the Interplanetary Magnetic Field (IMF) and solar wind cause high-latitude ionospheric transients observed by magnetic, optical and radar techniques, a coherent explanation…Read more on Ionospheric signatures of magnetopause pocesses
1 January, 1998 by Paul Rodhouse
Chiroteuthis veranyi (Férussac, 1835) (Cephalopoda: Chiroteuthidae) from South Georgia is described from material collected during the British Antarctic Survey's Offshore Biological Programme. The material closely resembles C. veranyi from elsewhere…1 January, 1998 by Eugene Murphy, Paul Rodhouse
Artificial selection pressures imposed by fisheries can impact population structure in the short term and drive evolution of life-history traits in the long term. In exploited squid populations the short…1 January, 1998 by Paul Rodhouse
The king penguin Aptenodytes patagonicus is a sub-Antarctic species that feeds primarily on mesopelagic fish and cephalopods in the vicinity of the Antarctic Polar Front (APF). We examined the cephalopod…Read more on Cephalopod predation by the king penguin Aptenodytes patagonicus from South Georgia
1 January, 1998 by Paul Rodhouse
The coleoid cephalopods (cuttlefish, squid and octopus) arose from their shelled ancestors during the late Devonian; they diversified in the Jurassic but did not radiate substantially until the Tertiary. Since…Read more on Physiological progenesis in cephalopod molluscs
1 January, 1998
Laser-based Fourier-Transform Raman spectroscopy (FTRS) has been used to identify in situ compounds of ecophysiological significance in diverse field-fresh Antarctic cryptoendolithic microbial communities. FTRS does not disrupt the community and…1 January, 1998
Modern ionosondes make almost simultaneous measurements of the time rate of change of phase path in different directions and at different heights. By combining these 'Doppler' measurements and angles of…Read more on Plasma drift estimates from the Dynasonde: comparison with EISCAT measurements