MESOSCALE RAINBANDS AHEAD OF COLD FRONTS IN NORTHERN CHINA AND THEIR DYNAMICAL MECHANISM ANALYSES

From the radar observations of 33 cold frontal systems which passed Beijing-Tianjing and Zhangjiakou area from May to August during 1963-1979, it was recognized that among the 33 systems there existed mesoscale rainbands in the warm sectors ahead of 31 cold fronts. According to the orientation, movement, formation and development of these rainbands, they are divided into three types:parallel, angulate, and perpendicular. In this paper the basic characteristics, generating sources and propagation of the three types of rainbands and the severe connective weather associated with the bands are presented. The possible mechanisms responsible for the formation and development of these rainbands are also briefly discussed.