Dome A Research Articles

Dome Argus: Ideal site for deep ice drilling

Located on the centre of ice drainage range, the highest Dome Argus (Dome A) of East Antarctic Ice Sheet (EAIS),could be represented as an ideal site for deep ice cores drilling containing oldest paleo-climate records. To select a suitable drillingsite for deep ice core, it needs gather all information pertaining to the local meteorology, ice sheet landforms, ice thickness, subglacial topography of bed rocks, ice velocity, internal structures of ice sheet, etc. Based on the International Partnerships in Ice CoreSciences (IPICS), we present recent achievement of glaciological research and its perspective at Dome A in this paper. We systematically discussed the merits and possible ventures of potential drilling sites around Dome A. Among all the candidates, we findthat the Chinese Antarctic Kunlun Station is the best site for carrying out the first deep ice core drilling campaign. We emphasizeand assess further the possibility to obtain a replicate core for studying dynamics and evolution of climate change.

Progress and prospects in Chinese Antarctic surveying,mapping and remote sensing studies

Antarctic surveying, mapping and remote sensing is one of the important aspects of the Chinese Antarctic geoscienceresearch program that stretch back over 25 years, since the first Chinese National Antarctic Research Expedition (CHINARE) in1984. During the 1980’s, the geodetic datum, height system and absolute gravity datum were established at the Great Wall andZhongshan Stations. Significant contributions have been made by the construction of the Chinese Great Wall, Zhongshan andKunlun Stations in Antarctica. Geodetic control and gravity networks were established in the King George Islands, Grove Mountainsand Dome Argus. An area of more than 200 000 km 2 has been mapped using satellite image data, aerial photogrammetry andin situ data. Permanent GPS stations and tide gauges have been established at both the Great Wall and Zhongshan Stations. Studiesinvolving plate motion, precise satellite orbit determination, the gravity field, sea level change, and various GPS applications foratmospheric studies have been carried out. Based on remote sensing techniques, studies have been undertaken on ice sheet andglacier movements, the distributions of blue ice and ice crevasses, and ice mass balance. Polar digital and visual mapping techniqueshave been introduced, and a polar survey space database has been built. The Chinese polar scientific expedition managementinformation system and Chinese PANDA plan display platform were developed, which provides technical support for Chinesepolar management. Finally, this paper examines prospects for future Chinese Antarctic surveying, mapping and remote sensing.

Record low surface air temperature at Vostok station, Antarctica

The lowest recorded air temperature at the surface of the Earth was a measurement of −89.2°C made at Vostok station, Antarctica, at 0245 UT on 21 July 1983. Here we present the first detailed analysis of this event using meteorological reanalysis fields, in situ observations and satellite imagery. Surface temperatures at Vostok station in winter are highly variable on daily to interannual timescales as a result of the great sensitivity to intrusions of maritime air masses as Rossby wave activity changes around the continent. The record low temperature was measured following a near‐linear cooling of over 30 K over a 10 day period from close to mean July temperatures. The event occurred because of five specific conditions that arose: (1) the temperature at the core of the midtropospheric vortex was at a near‐record low value; (2) the center of the vortex moved close to the station; (3) an almost circular flow regime persisted around the station for a week resulting in very little warm air advection from lower latitudes; (4) surface wind speeds were low for the location; and (5) no cloud or diamond dust was reported above the station for a week, promoting the loss of heat to space via the emission of longwave radiation. We estimate that should a longer period of isolation occur the surface temperature at Vostok could drop to around −96°C. The higher site of Dome Argus is typically 5–6 K colder than Vostok so has the potential to record an even lower temperature.

Preliminary results of the close-off depth and the stable isotopic records along a 109.91 m ice core from Dome A, Antarctica

A 109.91 m ice core was recovered from Dome A (or Dome Argus), the highest ice feature in Antarctica, during the 2004/05 austral summer by the 21st Chinese National Antarctic Research Expedition (CHINARE-21). Both methane profile along the core and firn densification model calculation suggest that the close-off depth is at about 102.0 m with an ice age about 4200 a. Stable isotopes (δ18O and δD) of the chips samples produced during each run of ice core drilling at Dome A, together with those of the other cores recovered from the eastern inland Antarctica, suggest a relative stable climate with a temperature fluctuation amplitude about ±0.6°C at the eastern inland Antarctica during the late Holocene. The average d-excess (or d =δ D-8δ18O) of 17.1‰ along the Dome A core is probably the highest among the Antarctic inland ice cores, which may be resulted from the kinetic fractionation during the snow formation under an oversaturation condition. Moreover, the increasing trend of d-excess during the late Holocene reflects mainly the migration of the water source area for precipitation at Dome A towards low latitudes. This paper presents the first results of a shallow ice core recovered from the unexplored highest area of the Antarctic ice sheet, providing a background for the proposing deep ice core drilling at Dome A.

Long (and Perilous) March Heralds China's Rise as Polar Research Power

SHANGHAI-- Although China got a late start in Antarctica, its scientists9 recent conquest of the highest point on Antarctica9s ice sheets, Dome Argus, could well make them the new darlings of Antarctic research. (Read more.)

Insoluble dust in a new core from Dome Argus, Central East Antarctica

Insoluble dust in a new core from Dome Argus, Central East Antarctica

Identifying areas of low-profile ice sheet and outcrop damming in the Antarctic ice sheet by ERS-1 satellite altimetry

A digital elevation model (DEM) of the surface of the Antarctic ice sheet is compared with a simple two-dimensional ice-flow model to illuminate gross distortions (>500 m) of the ice-surface elevation. We use a DEM derived from ERS-1 satellite altimetry, airborne data and TWERLE balloon data. This is compared with an ice-sheet elevation model generated by applying theoretical surface elevations, calculated for two-dimensional ice flow, to isolines of distance from the grounding line (continentality). The model is scaled using only one parameter, to match the measured surface elevation at Dome Argus. The model is far from rigorous, violating continuity conditions, ignoring variations in surface mass balance and temperature, and assuming uniform basal conditions. However, the comparison of model and observed surface elevations is illuminating in terms of the behaviour of the ice sheet at a continental scale. Across the ice sheet the rms difference between modelled elevation and the DEM is around 300 m, but much of this results from isolated areas of much greater disagreement. We ascribe these gross differences to the effects of basal conditions. in four areas, the observed surface is more than 500 m higher than the modelled surface. Most of these are immediately upstream of substantial areas of rock outcrop and are caused by the damming effect of these mountain ranges. in nine areas, the measured surface is more than 500 m lower than predicted. Eight of these areas, in West Antarctica and the Lambert Glacier basin, are associated with suspected areas of basal sliding. The ninth is an area of 250 000 km2 in East Antarctica not previously noted as having unusual flow characteristics, but for which very few-data exist. We speculate that this area results from unusual basal conditions resulting in a low-profile ice sheet. A low-profile ice sheet of this size with in the East Antarctic ice sheet indicates that basal conditions are perhaps more variable than previously thought.

Identifying areas of low-profile ice sheet and outcrop damming in the Antarctic ice sheet by ERS-1 satellite altimetry

A digital elevation model (DEM) of the surface of the Antarctic ice sheet is compared with a simple two-dimensional ice-flow model to illuminate gross distortions (>500 m) of the ice-surface elevation. We use a DEM derived from ERS-1 satellite altimetry, airborne data and TWERLE balloon data. This is compared with an ice-sheet elevation model generated by applying theoretical surface elevations, calculated for two-dimensional ice flow, to isolines of distance from the grounding line (continentality). The model is scaled using only one parameter, to match the measured surface elevation at Dome Argus. The model is far from rigorous, violating continuity conditions, ignoring variations in surface mass balance and temperature, and assuming uniform basal conditions. However, the comparison of model and observed surface elevations is illuminating in terms of the behaviour of the ice sheet at a continental scale. Across the ice sheet the rms difference between modelled elevation and the DEM is around 300 m, but much of this results from isolated areas of much greater disagreement. We ascribe these gross differences to the effects of basal conditions. in four areas, the observed surface is more than 500 m higher than the modelled surface. Most of these are immediately upstream of substantial areas of rock outcrop and are caused by the damming effect of these mountain ranges. in nine areas, the measured surface is more than 500 m lower than predicted. Eight of these areas, in West Antarctica and the Lambert Glacier basin, are associated with suspected areas of basal sliding. The ninth is an area of 250 000 km2 in East Antarctica not previously noted as having unusual flow characteristics, but for which very few-data exist. We speculate that this area results from unusual basal conditions resulting in a low-profile ice sheet. A low-profile ice sheet of this size with in the East Antarctic ice sheet indicates that basal conditions are perhaps more variable than previously thought.