【摘要】 利用常规探空资料，对３次不同系统产生的大暴雨天气过程进行了螺旋度分析，结果表明：暴雨区上空７００ｈＰａ以下螺旋度为正，３００ｈＰａ以上为负；暴雨产生在低层正螺旋度中心与高层负螺旋度中心相配合、中低层高温高湿和有对流不稳定能量储存的高能舌区。更多还原

【Abstract】 Conventional soundings were used to investigate the helicity in three rainstorm events related to different systems. It turns out that helicity is positive below 700 hPa and negative above 300 hPa over the rainband; rainfall is generated where the positive and negative helicity centers are available, high temperature and humidity areas existent at mid and low levels, and a highenergy tongue of convective unstable energy storage present.更多还原