Roll Clouds Associated with an East Asian Cold Front

On 11 January 1998, a cold front formed in southeast China as a result of a cold-air outbreak in northeast Asia. During this synoptic development, a series of roll clouds (along the SW–NE direction) was observed in East Asia; some of the clouds stretched for over a thousand kilometers. This roll cloud formation moved southeastward across Taiwan, the Ryukyu Islands, and Japan, and eventually into the open ocean. In order to explore the possible cause of these roll clouds the following preliminary analyses were made in this study: 1) the location of roll clouds relative to the cold front was determined in terms of the contrast between the infrared images of the Geostationary Meteorological Satellite of Japan and surface charts issued by the Japan Meteorologi-