关键词: 飑线, 地面中尺度结构, 移动特征, 观测分析

Abstract: The movement and the mesoscale surface structure of a squall line on April 23, 2007 in Guangdong is explored based on observations. It is shown that the moving direction of the squall line is parallel to the contours of the 1000?500 hPa layer thickness and the low-level vertical wind shear in front of the squall line. Meanwhile, the motion of the squall line can be estimated by the sum of inversed low-level jet and mean flow in the 850?300 hPa layer as proposed by Corfidi. Typical mesoscale surface structure of a squall line is observed including convergence and divergence lines, prelows, storm highs and wake lows. There is strong convergence line at the leading edge and in the back part of the squall line, and strong divergence line corresponding to the precipitation areas. The storm highs are between the divergence line and the convergence line in front of the squall line but much closer to the former, while the wake lows are behind the convergence line in the back of the squall line. These features of Guangdong squall line are also compared with those of squall lines in America.

Key words: squall line, mesoscale structural feature, movement, observation