A Case Study of the Severe Convective in Bohai Sea and the Establishment of Early Warning Index on the Sightseeing Boat

Abstract

Using the synchronous data such as weather radar, oceanic WRF model etc., a severe convective weather process has been analyzed on August 31, 2015 in Bohai Sea area, China. The results show that the shear line moved eastward and enhanced at the 925hPa and 850hPa in Bohai Bay from 08:00 to 20:00, the index K was 35 °C, index SI was -1.81 °C, the CAPE was 166 J/kg and the vertical wind shear was 16m•s-1 in the stratification curve at 08:00 A.M, because of this background, the severe convective weather occurred in Tianjin. The shear line moved northward at the 925hPa of the lower lay from 20:00 P.M on August 31to 08:00 A.M on September 1, the convective instability energy increased, several severe convective storm cell of meso-γscale and meso-βscale near the shear line have been induced in the central area of Bohai Sea, the new round of the was caused by a series of effecting of radar echo. Severe weather process CAPE was released by the strong vertical movement and water vapor convergence of the boundary layer, the cut-in of weaker dry and cold of Δθse (850-500 hPa) corresponded with the happening and impact area of the convection system in north of Liaodong bay. And this paper established the early warning model about the severe convective weather for the sightseeing boat in Bohai Sea.