【摘要】 利用多普勒雷达、TBB和NCEP1×1°再分析资料,对2008年8月1日发生在苏皖中部交界处的特大暴雨过程进行了分析。结果表明:特大暴雨过程是发生在减弱后的"0808"号台风环流与增强的副热带高压相互作用的背景下,西南低空急流增强和台风环流蜕变低槽东移分别触发了两段强降水的发生,对流层中低层强水汽辐合上升激发了台风残留环流内部对流云团发展和对流层中层有干冷空气从西北方向入侵,造成上干冷下暖湿的对流不稳定分别是两个时段的物理机制;最强降水发生在新生MCS的TBB梯度最大的部位,与其发展或移动方向一致;风向切变和"逆风区"的稳定维持以及500 hPa中尺度涡旋的出现是第二个强降水时段降水强度特大的直接原因。更多还原

【Abstract】 The torrential rain in Chuzhou on 1 August 2008 was analysed based on the NCEP 1×1 reanalysed data,TBB and Doppler radar data.The results showed that this heavy rainstorm process was composed of two periods of heavy rainfalls.It occurred on the background of weakening typhoon(Phoenix) circulation combined with enhancement of the West Pacific subtropical high.It was triggered separately by accretion of the southwest LLJ and the pressure trough degraded from typhoon circulation.It was caused by four MCSs.Heavy rainfall appeared in the maximal TBB gradient area of newly emerging MCS.Analysis of physical quantity and evolvement of the radar echoes showed that the interaction of the strongest moisture convergence in low-troposphere and inrush of dry cold air at middle levels was the physical mechanism of the heavy rain.The second stage of strong rainfall was caused mainly by shear line and adverse wind area appeared on Doppler base velocity and mesoscale vortex at 500hPa level.更多还原