The surface conditions of the inland ice sheet in east Dronning Maud Land, Antarctica, are derived from the NOAA-7 AVHRR data received at Syowa Station and then compared with the ground observations which were collected in November 1984 along a 243 km long traverse route at altitudes ranging from 2700 to 3400 m a.s.l. The variations in the AVHRR data are well related to the distribution of glazed surfaces. The areas with lower albedo, higher surface temperature, lower ratio of channel 2/channel 1, and lower T4-T5 coincide with the areas where a glazed surface has developed. This result is attributed to the fact that the glazed surface is composed of a multi-layered ice crust and that its radiative and thermal properties are closer to ice than to snow. The present study shows that the NOAA AVHRR data are useful for distinguishing bare ice, glazed surfaces, and snow surfaces of the Antarctic ice sheet.
Preliminary results of the analyses on 700 m ice cores retrieved from Mizuho Station, Antarctica, in 1983 and 1984 are presented. The majority of the physical properties, density, grain-size and shape, and total gas content, were measured at the drilling site. Fabrics, microparticle concentration, electrical conductivity, and stable-isotope concentration 6 18 0 were measured in laboratories after the cores had been taken to Japan.In spite of inaccuracy in measuring both density and total gas content in the ice, due to interlocking cracks in cores, several attempts were made to correct the data. The coincidence between the incremental peaks in the depth profile of the microparticle concentration, as well as in the electrical conductivity and the warm trend indicated by the 6 18 0 profile is discussed. The shape of the 6 18 0 profile is characterized by two inflection points and is compared with results obtained from the Byrd Station, Dome C and Vostok cores. From this comparison, it is tentatively concluded that the bottom of the Mizuho core may be an age of the order of 10 ka B.P .
SEM observations of microparticles in ice-core samples retrieved by the Japanese Antarctic Research Expedition in east Dronning Maud Land have been carried out since 1987. Morphology and elemental composition by EDS of many microparticles taken from various depths of the 700 m Mizuho ice core were compared with each other and with those of stratospheric microparticles in NASA Cosmic Dust Catalogs and microparticles hitherto found in deep ice cores retrieved in Antarctica. Number concentrations of microparticles were measured on all samples throughout the 700 m Mizuho ice core. Remarkable fluctuations found in the depth profile of the concentration seem to coincide with cold climates indicated by δ18O of the same core. Compositional analysis of volcanic ash at a depth of 500.7 m in the Mizuho ice core, dated at approximately 6000 years BP, indicates that the ash originated from the South Sandwich Islands.
Surface features were classified morphologically and described along oversnow traverse routes from the coast to the inland high plateau of east Queen Maud Land, Antarctica, during the 1984 and 1985 summer seasons. The distribution of surface features reveals regional characteristics which reflect differences in the regional deposition-erosion process.On the basis of observation of surface features and measurements of surface mass balance, the ice-sheet surface of east Queen Maud Land is sub-divided according to different environmental zones:(1)Ablation zone (below 700 m a.s.l.): melting of snow occurs. Dry snow line approximates the altitude where the maximum air temperature is 0°C.(2)Coastal continuous accumulation zone (700–1800 m a.s.l.): snow accumulation occurs continuously and the surface is flat because of high snow precipitation and a slight katabatic wind.(3)Discontinuous accumulation zone (1800–2500 m a.s.l.): a rough surface of sastrugi dominates this zone. Snow accumulation is discontinuous in space and time because of low snow precipitation and strong katabatic wind. Negative annual snow accumulation was observed at 20–30% of the stakes set every 2 km along the traverse route. Mizuho Station is located in this zone.(4)Long-term accumulation-free zone (2500–3400 m a.s.l.): long-term absence of snow accumulation occurs at the glazed surface, which consists of a multi-layered ice crust several millimetres thick. A glazed surface develops over a distance of 1–20 km when the surface undulation is steeper, and covers 30–50% of the area in this zone. A hiatus sequence of snow accumulation is thought to continue for about 10–100 years over the glazed surface region.(5)Inland continuous accumulation zone (above 3400 m a.s.l.): a flat surface dominates in this zone. Snow accumulation occurs continuously because there is a weak katabatic wind in the central high plateau in spite of a very small amount of precipitation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.