集中海難をもたらした瀬戸内海の真冬の濃霧について(日本航海学会第41回講演会)

抄録

The dense winter fog crippled Inland Sea Services for two days, Feb. 12 and Feb. 13 of 1969 was so called radiation fog and many collisions and agrounds were reported around the Inlad Sea region. So the author investigated the winter radiation fog in western Japan with the object of forecasting it synoptically and locally using the surface and upper meteorologlcal elements. Analyses indicate the following features. (1) Migratory high prevailed in western Japan in synoptic surface map. (2) Cold core was seen in the central area of the Inland Sea in local map. (3) The distribution of saturation deficit was nil or very little. (4) The deviation of maximum temperature and minimum temperature were very little at Takamatsu and Okayama. (5) The area of divergence was extended in the central part of the Inland Sea on Feb. 1200z. (6) Warm core was seen off Kyushu and Shikoku in synoptic 850 MB map. (7) Inversions were analysed in ascent curves at Shionomisaki and Yonago. (8) Air pollution from the seaside heavy industrial zones like as Hanshin, Mizushima, Sakaide, Hiroshima, Ube and Kyushu heavy industrial zone were considered to be the important factor of fog occurrence in the Inland Sea region.