Current observations on the development of the Yellow Sea Warm Current

Historically, the climatological mean northward flow in the Yellow Sea trou gh has been referred to as the Yellow Sea Warm Current (YSWC) since it was thought to originate as a branch of the Tsushima Current which transports w arm Kuroshio waters. However, the Tsushima Current does not penetrate into the Yellow Sea interior during winter. The onset of what is referred to as the YSWC during winter is directly observed using measurements of current p rofiles, pressure, and temperature, and a wind climatology for the time per iod July 1995 through January 1996. The YSWC is a result of weak southerly winds during summer. During fall transition and winter monsoon periods, str ong northerly wind bursts drive a north-to-south rise in pressure extending from the trough over to the Korean coast and force a northward flow in the Yellow Sea trough. The rise in pressure and corresponding north wind-force d YSWC begin at the end of October for this measurement period and are obse rved into January. These measurements show that the YSWC has different seas onal forcing mechanisms. Direct current measurements are also presented whi ch suggest a current flow north of Cheju, sometimes referred to as the Chej u Warm Current.