Search

Ice-surface elevation profiles of more than 30 000 km in total length are derived from kinematic GNSS (GPS and the Russian GLONASS) observations on sledge convoy vehicles along traverses between Vostok Station and the East Antarctic coast. These profiles have accuracies between 4 and 9 cm. They are used to validate elevation data sets from both radar and laser satellite altimetry as well as four digital elevation models. A crossover analysis with three different processing versions of Envisat radar altimetry elevation profiles yields a clear preference for the relocation method over the direct method of slope correction and for threshold retrackers over functional fit algorithms. The validation of CryoSat-2 low-resolution mode and SARIn mode data sets documents the progress made from baseline B to C elevation products. ICESat laser altimetry data are demonstrated to be accurate to a few decimetres over a wide range of surface slopes. A crossover adjustment in the region of subglacial Lake Vostok combining ICESat elevation data with our GNSS profiles yields a new set of ICESat laser campaign biases and provides new, independent evidence for the stability of the ice-surface elevation above the lake. The evaluation of the digital elevation models reveals the benefits of combining laser and radar altimetry. [ABSTRACT FROM AUTHOR]

This paper is concerned with the study of expedition activity in Antarctica as a part of the search for useful analogies and solutions which can be taken into account in planning manned missions to the Moon and Mars. The following is considered: natural analogies, human factors, station facilities, means of transportation, scientific programs, safety issues, and historical and political analogies. A rationalization is given for the idea of creating a testing ground in Antarctica (stations Vostok, Novolazarevskaya, Jetty Oasis) for ground-based simulation of functioning of a lunar and Martian base. [ABSTRACT FROM AUTHOR]

Nondestructive technology has been developed for the extraction of light gases dissolved in ice. The technology has been tested on samples of atmospheric and congealed ice of the 5-G3 bore hole of the Vostok station (East Antarctica) extracted from depths of 3457-3698 m. Down to 3539 m, ice is of an atmospheric origin, while ice deposited deeper is formed by natural water of Vostok Lake frozen on the glacier. Light gases were extracted into samplers (glass flasks) in the course of the 3-day degassing of samples freshly elevated from a bore hole. The samples were analyzed on the FT-1 time-of-flight mass spectrometer 6 months after sampling. Measurements reveal the presence of amounts of helium as well as molecular hydrogen considerably exceeding the atmospheric values. Measured values of gas ratio H/He = 5.4 ± 1.9 in the samples from depths of 3596-3698 m exceed the atmospheric values by more than an order of magnitude. [ABSTRACT FROM AUTHOR]

This paper documents the drilling of the 5G deep hole at the Russian Vostok station, Antarctica. The hole construction is described and the specifications of the drill and surface drilling equipment are given. The peculiarities of drilling at various depths are considered. Based on the extensive experimental data collected at Vostok station, the processes occurring at the hole bottom are investigated: ice breaking and cutting, bottom cleaning and chip transport, and accumulation of the chips in the screen. The main factors affecting ice-drilling efficiency are the coarseness of ice crystals and the ice temperature. When ice crystal size exceeds 10 mm the cutting efficiency sharply decreases, and when ice temperature exceeds -5°C the chip transport from the hole bottom and the chip density in the screen are reduced. The drill advance then becomes irregular, slows down and may even be terminated in some cases. Optimal values of the basic drilling parameters (e.g. cutter head rotation rate and drilling fluid flow rate in the circulation system) have been deduced empirically. The designs of the cutter head and circulation system including screens have been significantly modified, allowing the drilling process to proceed at a normal rate even in the vicinity of the subglacial lake surface. [ABSTRACT FROM AUTHOR]