Thinning of the Ice Sheet Estimated from Total Gas Content of Ice Cores in Mizuho Plateau, East Antarctica

Kameda, Takao; Nakawo, Masayoshi; Mae, Shinji; Watanabe, Okitsugu; Naruse, Renji

doi:10.3189/s0260305500008429

Cited by 11 publications

(4 citation statements)

References 22 publications

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“…Richardson and others, 1997). Although increasing accumulation rates have been reported for many sites (Pourchet and others, 1983; Peel and Mulvaney, 1988; Morgan and others, 1991; Mosley-Thompson and others, 1995), other sites show decreasing trends (Graf and others, 1990; Kameda and others, 1990; Bindschadler and others, 1993; Isaksson and Karlén, 1994; Ren and others, 1999). A similar situation is seen for isotope temperature records (Isaksson and others, 1996; Ren and others, 1999; Xiao and others, 2001).…”

Section: Introductionmentioning

confidence: 94%

Meteorological and glaciological evidence for different climatic variations on the east and west sides of the Lambert Glacier basin, Antarctica

Xiao

Allison²,

Ren³

et al. 2004

Ann. Glaciol.

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Surface mass-balance studies and climatic records from firn cores show remarkable differences between the east and west sides of the Lambert Glacier basin (LGB). The spatial distribution of the surface accumulation is influenced by the atmospheric moisture flux, and by the surface wind field, which is largely determined by topography. Atmospheric water-vapor budget data for the ice-sheet sector covering the basin (45–90˚ E) show that on the east side of the LGB the moisture flux is poleward, averaging 18 kgm–1 s–1 in 1988, while for the west side it is Equatorward, averaging 5 kgm–1 s–1. A similar pattern, but with much lower transport of vapor flux, is seen across 70˚ S. Two firn cores from the east side of the basin and two from the west side were analyzed to determine accumulation-rate and temperature-proxy variations for the past 50 years. The trends were opposite on the different sides of the basin. Similar opposing trends are seen in meteorological records from Davis and Mawson coastal stations, situated on the east and west sides of the LGB respectively. There is a good correlation between the accumulation/18O record in ice cores from the eastern LGB and the sea-level pressure (obtained from the US National Centers for Environmental Prediction/US National Center for Atmospheric Research (NCEP/NCAR) re-analyses) of a Southern Indian Ocean low (SIOL), but not between the SIOL and the records from the western LGB. This study reveals that variations in local circulation could alter at least the annual to decadal time-scale climate records, and may result in completely different climate histories between adjacent areas.

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Section: Introductionmentioning

confidence: 94%

Meteorological and glaciological evidence for different climatic variations on the east and west sides of the Lambert Glacier basin, Antarctica

Xiao

Allison²,

Ren³

et al. 2004

Ann. Glaciol.

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“…Ice dynamics observations in this study area is consistent with our idea. As of 1978, the rate of ice thinning near Mizuho has been about 1 m/yr [ Naruse , 1979] and this thinning probably started about 2000 years ago [ Kameda et al , 1990]. Moreover, the age of ice at 700 m depth is 9400 years at Mizuho Station [ Nakawo et al , 1989].…”

Section: Cof Development Along Ice Flow and Its Effect On Ice Sheet Dmentioning

confidence: 99%

Crystal orientation fabrics within the Antarctic ice sheet revealed by a multipolarization plane and dual‐frequency radar survey

et al. 2003

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[1] To investigate the viscosity structure of ice sheets induced by crystal orientation fabric (COF), we carried out a multipolarization plane and dual-frequency radar survey in East Antarctica. Radar surveys were done along a 670-km-long flow line from Dome Fuji toward the coast and two transverse lines of 300-km and 20-km length, respectively. The radar echoes were highly dependent on the polarization plane for ice depths between about 40 and 60% of the ice thickness in the lower reaches of the convergent ice flow sector approaching the outlet glacier. When the polarization was perpendicular to the ice flow, echoes were about 10 dB stronger than when the polarization was parallel to the ice flow. This feature was not clear in the upper part of this convergent flow sector. Farther inland, where ice flow is divergent or parallel, the radar echo varied by several decibels because of changes of the radar polarization and had maxima in two orientations. Dual-frequency data showed that the cause of the reflections was changes in COF. Multipolarization data identified anisotropic reflectivities and birefringence as causes of the anisotropic radar echoes in the lower and upper reaches, respectively. With the aid of ice-core-based studies on COF, we show that ice is composed of stacked layers of single-pole and vertical girdle fabrics in the lower reaches. In contrast, we argue that changes of single-pole clustering cause isotropic reflectivities in the upper reaches. We also discuss on the development of COF along ice flow and its implication to ice sheet dynamics.INDEX TERMS: 0669 Electromagnetics: Scattering and diffraction; 0933 Exploration Geophysics: Remote sensing; 1827 Hydrology: Glaciology (1863); 6969 Radio Science: Remote sensing; KEYWORDS: ice-penetrating radar, internal layers Citation: Matsuoka, K., T. Furukawa, S. Fujita, H. Maeno, S. Uratsuka, R. Naruse, and O. Watanabe, Crystal orientation fabrics within the Antarctic ice sheet revealed by a multipolarization plane and dual-frequency radar survey,

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“…But at MGA, western LGB, annual accumulation rates during the same period display an obviously decreasing trend. Although a decreasing accumulation rate has occasionally been reported (Graf and others, 1990; Kameda and others, 1990; Bindschadler and others, 1993), most studies reveal that accumulation rates have been increasing recently in Antarctica (Pourchet and others, 1983; Peel and Mulvaney, 1988; Morgan and others, 1991; Mosley-Thompson and others, 1995). This suggests a complexity, either in the spatial or in the temporal sense, of the accumulation-rate variation over the continent.…”

Section: Spatial and Temporal Variations Of Accumulation Ratementioning

confidence: 99%

Primary results of glaciological studies along an 1100 km transect from Zhongshan station to Dome A, East Antarctic ice sheet

et al. 2000

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ABSTRACT. The Chinese National Antarctic Research Expedition (CHINARE)carried out three traverses from Zhongshan station to Dome A, Princess Elizabeth Land and Inaccessible Area, East Antarctic ice sheet, during the 1996/97 to 1998/99 Antarctic field seasons. The expeditions are part of the Chinese International Trans-Antarctic Scientific Expedition program. In this project, glaciological investigations of mass balance, ice temperature, ice flow, stratigraphy in snow pits and snow/firn ice cores, as well as the glaciochemical study of surface snow and shallow ice cores, have been carried out. In the 1998/99 field season, CHINARE extended the traverse route to 1128 km inland from Zhongshan station. The density profiles show that firnification over Princess Elizabeth Land and Inaccessible Area (290^1100 km along the route) is fairly slow, and the accumulation rate recovered from snow pits along the initial 460 km of the route is 4.6^21cm (46^210 kg m^2a^1) water equivalent. The initial 460 km of the route can be divided into four sections based on the differences of accumulation rate. This pattern approximately coincides with the study on the Lambert Glacier basin (LGB) by Australian scientists. During the past 50 years, the trends of both air temperature and accumulation rate show a slight increase in this area, in contrast to the west side of the LGB. Data on surface accumulation rates and their spatial and temporal variability over ice-drainage areas such as the LGB are essential for precise mass-balance calculation of the whole ice sheet, and are important for driving ice-sheet models and testing atmospheric models.

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Thinning of the Ice Sheet Estimated from Total Gas Content of Ice Cores in Mizuho Plateau, East Antarctica

Cited by 11 publications

References 22 publications

Meteorological and glaciological evidence for different climatic variations on the east and west sides of the Lambert Glacier basin, Antarctica

Meteorological and glaciological evidence for different climatic variations on the east and west sides of the Lambert Glacier basin, Antarctica

Crystal orientation fabrics within the Antarctic ice sheet revealed by a multipolarization plane and dual‐frequency radar survey

Primary results of glaciological studies along an 1100 km transect from Zhongshan station to Dome A, East Antarctic ice sheet

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