KOHSHIMA Shiro Tokyo Univ. of Technology, Biology, Assoc. Prof., 生命理工学部, 助教授 (60183802)
KOBAYASHI Shunnichi Niigata Univ., Center for Snow Disaster, Prof., 積雪地域災害センター, 教授 (70001659)
NARUSE Renji Hokkaido Univ., Inst. of Low Temp. Sci., Assoc. Prof., 低温科学研究所, 助教授 (10002099)
SHIRAIWA Takayuki Hokkaido Univ., Inst. of Low Temp. Sci., Assist. Prof., 低温科学研究所, 助手 (90235739)
リベラ アンドレ チリ大学, 地理学科, 助手
カサッサ ジーノ マガジャーネス大学, 南極プログラム,チリ, 助教授
和泉 薫 新潟大学, 積雪地域災害研究センター, 助教授 (50114997)
|Budget Amount *help
¥11,000,000 (Direct Cost : ¥11,000,000)
Fiscal Year 1999 : ¥4,900,000 (Direct Cost : ¥4,900,000)
Fiscal Year 1998 : ¥6,100,000 (Direct Cost : ¥6,100,000)
In 1998, the following results were obtained from field work in the Northern Patagonia Icefield. As for the study of the Holocene glacier variation of Soler Glacier, and Nef glacier in the valley of Soler River, the distribution and location of terminal moraines suggest the existence of the Younger Dryas advance (ca. 10,500 BP) and the Neoglaciation II (ca. 2000 BP) ; however, these suppositions awaits for confirmation by carbon 14 and cosmic ray datings. At Soler Glacier, glacier flow, the surface profile, strain rates were measured at the ablation area, along with hydrological and meteorological observations. Findings include that the amount of the basal slip accounts a large part of the glacier flow. The measurement of the surface profile revealed that the surface elevation decreased by 42 ± 5 m since 1986, with the mean annual thinning rate of 3.2 ± 5 m.
Aerial photographic survey in 1998 of snouts of outlet glaciers of the Northern Patagonia Icefield revealed glacier variations sin
ce 1995 when it was done last time. All outlet glaciers but one (San Rafael Glacier) are found to have retreated during this period. Aerial photographic survey in 1999 disclosed a very interesting phenomenon. San Rafael Glacier, which was only glacier advancing since 1993, was found to have retreated between 1998 and 1999. From this observation, it is postulated that the unusual advance of San Rafael Glacier may no be attributed to the rainfall increase during the early 1970s as supposed before, but may be attributed to fjord topography and glacier dynamics.
In November-December 1999, ice drilling was accomplished at the accumulation area of Tyndall Glacier of the Southern Patagonia Icefield, acquiring ice-core samples of 46 m long, along with in situ observation. Detailed chemical analyses of the ice-core will be done in the near future. At Perito Moreno Glacier, Calving activities were measured with photogrammetric measurements and the amount of calving was estimated by recording tidal waves caused by calving. Bathymetric survey of the lake was also done, revealing the depth near the glacier front down to 80 m deep. The depth of Brazo Upsala, into which Upsala Glacier is flowing, was measured, with the maximum depth close to 700 m. Bathymetric data are important to analyze the relationship between calving activities, glacier dynamics and glacier variations. Less