An investigation has been carried out to explain the formation mechanism of a long convection band (CB) occurred over the Yellow Sea on 2 August 2008. Observed CB formed along the axis of an elongated low-level trough across the Yellow Sea in a roughly neutral to weakly unstable environment. The CB at mature stage was about 300 km in length and 15~20 km in width with no stratiform precipitation. And its behavior was quasi-stationary for about 7 hours from initiation (2200 UTC 1 0500 UTC 2 August). Both observation and numerical simulation showed that the CB was initiated to the south of surface wind shift line, where SW-WSW prevailed. Simulated CB forms along a narrow convergence line, which is referred as a convergence line inducing convection band (CL-CB), in a simultaneous manner along the entire band. Initiation and development mechanisms of the CL-CB have been examined using the simulated results and vorticity budget analysis.
Formation mechanism of a long convection band over the Yellow Sea