【摘要】 1998年 6、 7月长江中游雨量集中 ,两月总雨量 734 .7mm;1 999年 6月长江中、下游雨量分别为 32 5 .5、 6 36 .2 mm,安庆、上海月雨量均为 1 949年以来同期最高值。南亚高压东北侧存在一高空急流 ,中低层西太平洋副热带高压西北侧为一低空急流 ,两急流轴线间为宽广的近东西向垂直上升运动区 ,并伴有湿舌和涡旋存在 ,构成季风流管。长江流域受季风流管影响 ,产生大到暴雨。更多还原

【Abstract】 The characteristics of the precipitation over the middle reaches of the Changjiang river are concentrated rainfall and the total rainfall amount is 734 7mm from June to July in 1998.In June,1999,the rainfall amount over the middle reaches of the Changjiang river is 325 5mm,the rainfall amount over the lower reaches of the Changjiang river is 636 2mm.The monthly rainfall amount is maximum in Anqing and Shanghai since 1949.The upper level jet lays in the northeast of South Asia high,the low level jet lays in the northwest of subtropical Pacific high in middle and lower atmosphere.There is a upward current and a wet tongue associated with vortex and hard rain between the upper level jet and the low level jet.This is of the characteristics of monsoon stream tube.更多还原