1. Geochemical Research Department, Meteorological Research Institute, Nagamine 1-1, Tsukuba, Ibaraki 305, Japan
2. Marine Department, Japan Meteorological Agency, Otemachi 1-3-4, Chiyoda-ku, Tokyo 100, Japan
3. Ocean Research Department, Japan Marine Science and Technology Center, Natsushima 2-15, Yokosuka, Kanagawa 237, Japan
4. Research Division, Research and Investigation Bureau, Institute for Sea Training, Ministry of Transport, Kitanakadori 5-57, Naka-ku, Yokohama, Kanagawa 231, Japan