Subarctic Gyre in the North Pacific Ocean.

The circulation nature in the Subarctic Gyre in the North Pacific, and the water mass modification processes found there are discussed. The circulation path penetrates well inside the Bering Sea, and a part of the water enters into the Okhotsk Sea. The water masses are modified significantly in and near these marginal seas. The Oyashio Water is shown to be formed by mixing between the East Kamchatka Current Water and the Okhotsk Sea Water. The freshest water in the intermediate layers is found in the Okhotsk Sea, and appears to play important role in the formation of the North Pacific Intermediate Water.