【摘要】 利用NECP1°×1°6h再分析资料和WRF中尺度数值模式对2006年7月2—3日豫北区域性大暴雨过程进行数值模拟,并用模拟结果对该过程作中尺度分析。结果表明:暴雨中尺度系统发展和维持期间,基本上是强涡度区对应强辐合区,使得垂直对流运动发生发展,为强降水发生和持续提供了动力条件;θse值大小和实况降水强弱演变对应关系很好,θse值越大,实况降水越强,反之,实况降水越弱;豫北地区出现强降水时,水汽通量中心位于豫南且分布在西南急流轴上,豫中南部始终维持一条明显的水汽输送带,水汽被源源不断地输送到豫北地区;豫北地区处于明显的水汽辐合区,强辐合区有一自西向东的移动过程,与实况强降水过程演变趋势一致;大暴雨区域上空从低层到对流层顶层垂直螺旋度均为正值,且强降水时段与螺旋度最强时段对应关系很好,降水峰值与正螺旋度中心出现时间吻合。更多还原

【Abstract】 With the 1°×1° NCEP reanalysis data and WRF mesoscale model,the heavy rainstorm in Northern Henan from 2 to 3 July 2006 is simulated to study the formation mechanism of the mesoscale rainstorm system.In the period of the system progress and maintenance,it shows that the zone of strong positive vorticity corresponds to the zone of strong convergence.Obviously the corresponding relation can enhance the occurrence and progress of vertical convection and provide dynamical condition for the heavy rainstorm.It is found that the value of θse commendably corresponds to precipitation of the heavy rainstorm.The bigger the value of θse,the heavier the precipitation,and vice versa.During the heavy rainstorm over Northern Henan,the center of vapor flux locates Southern Henan and the axis of the southwest jet,an obvious vapor transporting belt always maintains over the south central Henan and water vapor is carried to Northern Henan constantly.A clear convergence zone of water vapor over Northern Henan moves from west to east just as the evolution tendency of the heavy rainstorm.The heavy rainfall period is closely related with the higher positive vertical helicity,the appearance of the peak value of precipitation is synchronized with that at the center of the positive vertical helicity.更多还原