An Investigation on the Variations of Sea Level due to Meteorological Disturbances on the Coast of Japanese Islands (II)

Storms Surges on the Coast of the Japan Sea

Abstract

Storm surges on the eastern coastal line of the Japan Sea are studied. In contrast with the Pacific coast, extraordinary destructive surges hardly develop there because shallow waters such as bays or a continental shelf are comparatively small. Generally speaking, the effect of atmospheric pressure is roughly hydrostatic, and northeasterly winds cause the descent of sea level and southwesterly winds the ascent of it since the shore line runs from southwest to northeast. However, the fluctuations of sea level are different remarkably according to the course of atmospheric disturbances as well as topography of the coast. Case studies are made in detail for four storms which took different courses. In some cases we can clearly recognize a typical external surge which follows the storm considerably later at a very low speed of about 3-4m/sec along the continental shelf from the southern entrance of the sea to Noto Peninsula. Its low speed is explained by assuming a shelf wave of Robinson's type. A curious fact that the sea level sinks before the arrival of the storm is also discussed.