强弱降水超级单体风暴雷达回波特征对比分析

Comparative Analysis of CINRAD/SA Echo Features between Severe and Weak Precipitation Supercells

应用天气图、卫星云图资料,重点应用天津新一代天气雷达(CINRAD/SA)产品,对2002年7月15日发生在天津市宁河县的冰雹天气过程和2005年8月16日发生在天津地区的强降水天气过程进行对比分析,重点分析了速度图上中尺度系统的回波特征和反射率图上的图像特征。结果表明:虽然产生这两次强对流天气的影响系统不同,但雷达回波上显示都是超级单体风暴,强降水超级单体风暴产生的是77.5 mm.h-1的暴雨且回波移动方向不会发生改变;弱降水超级单体风暴产生的是直径40 mm的大冰雹且回波移动方向发生了180°的改变。速度图上的特征也不相同,强降水超级单体风暴显示的是"逆风区"特征;弱降水超级单体风暴显示的是中气旋特征。对回波转向原因进行了分析,得出了回波将向核区直径较大、旋转速度较大的中气旋所在方位转向的结论。

A comparative analysis is made of a hail process at Ninghe County on 15 July 2002 and a heavy precipitation at Tianjin on 16 August 2005 by using of weather maps, cloud images, and Tianjin CINRAD/ SA products, The emphasis is put on the echoes of mesoscale systems on the velocity field and the image features on the intensity field, The results indicate that though the influencing systems for the two processes are different, there appeared supercell storms on the radar echo images of both, with the heavy supercell accompanying a heavy rain of 77,5 mm per hour and the weak one having hailstones of about 40 mm in diameter, The characteristics on the velocity chart are different too, The heavy precipitation supercell shows the characteristic of ＂adverse wind area, ＂ while the weak storm shows the characteristic of mesocyclones. The direction turning of radar echoes is also studied and the analysis shows that radar echoes turned to the area with greater hail diameter the rotational velocity in the mesocyclone.