Perspectives on Sea- and Lake-Effect Precipitation from Japan’s “Gosetsu Chitai”

Abstract

AbstractA remarkable snow climate exists on the Japanese islands of Honshu and Hokkaido near the Sea of Japan. Mean annual snowfall in this “gosetsu chitai” (heavy snow area) exceeds 600 cm (235 in.) in some near-sea-level cities and 1,300 cm (512 in.) in some mountain areas. Much of this snow falls from December to February during the East Asian winter monsoon when frequent cold-air outbreaks occur over the Sea of Japan. The resulting sea-effect precipitation systems share similarities with lake-effect precipitation systems of the Laurentian Great Lakes of North America, but are deeper, are modulated by the regional coastal geometry and topography, and can sometimes feature transversal mode snowbands. Snowfall can maximize in the lowlands or the adjoining mountains depending on the direction and strength of the boundary layer flow. Remarkable infrastructure exists in Japan for public safety, road and sidewalk maintenance, and avalanche mitigation, yet snow-related hazards claim more than 100 lives annually. For winter recreationists, there is no surer bet for deep powder than the mountains of Honshu and Hokkaido near the Sea of Japan in January, but the regional snow climate is vulnerable to global warming, especially in coastal areas. Historically, collaborative studies of sea- and lake-effect precipitation systems involving North American and Japanese scientists have been limited. Significant potential exists to advance our understanding and prediction of sea- and lake-effect precipitation based on studies from the Sea of Japan region and efforts involving meteorologists in North America, Japan, and other sea- and lake-effect regions.