Japanese ice core studies in the polar regions

A 2,500-m-deep ice core drilling project is planned by Japanese glaciologists at the top of the ice sheet in Queen Maud Land, the second highest dome of the Antarctic ice sheet. The deep drilling will be carried out during 1993-1995 at a new inland base (77 degree 22 minutes S, 39 degree 37 minutes E, 3807 m a.s.1.), 1,000 km away from Syowa Station (69 degree 00 minutes S, 30 degree 35 minutes E). The purpose of this project is to reconstruct climatic and environmental records during the past 15-20K years and also to obtain glaciological data relating to the ice sheet formation and the mass balance processes. This deep drilling is a project developed from a series of drilling projects started at Mizuho Station in 1971. In August 1984, drilling at Mizuho Station reached a depth of 700.6 m. This core is estimated to cover the last 9,400 years. Ice core drilling in the Arctic and also in the third polar region, i.e., the Himalayas and Kunlun Mountains, was also carried out in recent years. In 1983, glacier drilling to a depth of 70 m at 5,400-m elevation in the Himalayas, and 86-m- deep drilling to the bottom in Svalbard were accomplished in 1987. A 205-m-deep drilling was carried out in southern Greenland in 1989. In this paper, the results obtained by these drilling projects will be reviewed and the prospect of the authors new drilling projects will be introduced