ロシア連邦サハ共和国スンタル・ハイアタ山脈のNo. 31氷河に関する予察研究

We carried out a preliminary glaciological research on the No.31 Glacier in the Suntar Khayata Range, Sakha Republic, Russian Federation, in the summer of 2001. This glacier was intensively studied, including mass balance, ice temperature measurements and surveying, by Russian researchers in 1957-58 (the 3 rd International Geophysical Year) (Koreisha, 1963). We aimed to obtain the change of the glacier volume since 1958 to study climate change during the last 40 years, and to know the possibility of ice core drilling and analyses for paleoclimatic study in the eastern Siberia. The glacier is a valley-type cold glacier of approximately 3.85 km long and covers the altitude from 2728 m to 2050 m a.s.l. The accumulation area of the glacier is mostly underlain by superimposed ice, which is slightly capped with water-saturated firn. The ablation area is characterized by well-developed longitudinal foliations, and basal ice layers at the very end of the terminus. The air temperature was as high as 12.7 °C in average at the Base Camp (ca. 2000 m a.s.l.) during the observation period (July 21-27, 2001), and we observed intensive melting at the whole area of the glacier. From this observation, we conclude that the glacier is not suitable for the ice core study because it is probably difficult to reconstruct a continuous ice core climate record. Beside glaciological studies, we conducted a topographical survey of the glacier, which showed that the glacier terminus had retreated approximately 200 m in distance and lowered by approximately 20 m from 1957-59 to 2001.