洱海流域致洪降水过程的雷达预警指标研究

Research on radar warning indicators of flood induced precipitation processes in Erhai Lake basin

  • 摘要: 为更准确预报洱海流域的致洪性降水天气过程,利用地面气象站、卫星、雷达等多源资料,通过对局地和区域性强降水过程的详细分析,得出洱海流域致洪降水的雷达预警指标:反射率因子图上有回波强度在45 dBz以上的强回波区或者以层状云回波为主的层积混合降水回波,且强回波区维持时间较长,降水过程中反射率因子图上出现零度层亮带;多个时次不同仰角的径向速度图上出现辐合区和逆风区特征. 垂直液态水含量有明显的增加趋势,局地强降雨时多个体扫垂直液态水含量超过15 kg/m2,区域性强降雨时多个体扫垂直液态水含量在1~5 kg/m2;局地强降雨时回波顶最高达到12~15 km,区域性强降雨时大部地区回波顶为5~6 km,最高能达8~9 km.

     

    Abstract: In order to more accurately forecast the flood causing precipitation weather process in Erhai Lake basin, multi-source data such as automatic weather stations, satellites, and radars were used. The radar warning indicators for flood induced precipitation in Erhai Lake basin were obtained through the detailed analysis of radar characteristics of local and regional heavy precipitation processes. On the reflectivity factor map, there are strong echo regions with echo intensity above 45 dBz or stratified mixed precipitation echoes dominated by stratiform cloud echoes, and the strong echo regions maintain for a long time, and bright bands of zero degree layer appear during the precipitation process. The convergence and upwind areas appear on the radial velocity maps with different elevation angles for multiple times. The vertically integrated liquid water content (VIL) shows an obvious increasing trend, with the VIL of multiple volume scans exceeding 15 kg/m2 during local heavy rainfall, and ranging from 1 to 5 kg/m2 during regional heavy rainfall. The maximum top height of echo can reach 12−15 km during local heavy rainfalls, while the top height of echo in most areas is 5−6 km during regional heavy rainfall, with a maximum of 8−9 km.

     

/

返回文章
返回