Okitsugu Watanabe

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The Milankovitch theory of climate change proposes that glacial-interglacial cycles are driven by changes in summer insolation at high northern latitudes. The timing of climate change in the Southern Hemisphere at glacial-interglacial transitions (which are known as terminations) relative to variations in summer insolation in the Northern Hemisphere is an(More)
Recent ice core studies have raised the disturbing possibility that glacial-interglacial climate changes may be non-uniform across Antarctica. These findings have been confined to records from the Ross Sea sector of the continent, but significant deviations in other areas would call into question the widely assumed validity of the climate record obtained(More)
One-dimensional (1-D) ice flow models are used to construct the age scales at the Dome C and Dome Fuji drilling sites (East Antarctica). The poorly constrained glaciological parameters at each site are recovered by fitting independent age markers identified within each core. We reconstruct past accumulation rates, that are larger than those modelled using(More)
Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000(More)
Ž Mechanical tests have been performed on strongly textured ice samples coming from a wide range of depths from 1328. Ž. down to 2868 m of the GReenland Ice core Project GRIP for different sample orientations with respect to the prescribed stress. In this way, two directional viscosities, corresponding to the ''easy glide'' and to the ''hard glide''(More)
Introduction Conclusions References Tables Figures ◭ ◮ ◭ ◮ Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU Abstract 1-D ice flow models are used to construct the age scales at the Dome C and Dome Fuji drilling sites (East Antarctica). The poorly constrained glaciological parameters at each site are recovered by fitting(More)
Fluxgate magnetometer data recorded at the with higher accuracy of timing (0.1 s) and amplitude resolution (0.01 nT) were utilized to survey an onset of Pi 2 pulsations in the midnight sector (2100±0100 LT) during PROMIS (Polar Region and Outer Magnetosphere International Study) periods (1 March±20 June, 1986). It is found that changing ®eld line magnitude(More)
An intensi®cation of auroral luminosity referred to as an auroral break-up often accompanies the onset of geomagnetic pulsation (Pi 2) at the dip-equator. One such auroral break-up occurred at 2239 UT on 16 June, 1986, being accompanied by weak substorm activity (AE$50 nT) which was recorded in all-sky image of Syowa Station, Antarctica (66.2°S, 71.8°E in(More)
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