A case study of Japanese coastal frontogenesis

Abstract

Coastal frontogenesis, which has been extensively studied off the east coast of the United States, proves to be an operational forecasting problem as well as a possible link to explosive cyclogenesis. Similar conditions that produce coastal fronts along the U.S. coast also exist over the western North Pacific Ocean off the coast of Japan. However, few studies have examined the mesoscale coastal phenomena that precede Asian coastal cyclogenesis. Therefore, a synoptic and mesoscale analysis was completed for an area near Tokyo, Japan prior to a 23 March 1986 explosive cyclogenetical event. Synoptic­ scale analyses fail to pick up the details of any possible coastal frontogenesis. Results from the mesoscale analyses indicate that convergence and frontogenesis begin along the coast 24 hours prior to the cyclogenesis. The coastal frontogenesis seems to begin just inland as discrete regions of frontogenesis and then move offshore as a more or less continuous feature just prior to the passage of the cyclone. Imagery from the Japanese GMS satellite supports the sequence of events suggested by the mesoscale analyses. However, future studies will need a more complete data network especially over the water to further characterize this mesoscale phenomenon.