应用M icaps常规资料和FY-2卫星资料,对2002,2003年夏季滇中玉溪地区出现的15次冰雹天气过程进行分析,得出夏季滇中玉溪地区产生冰雹天气的天气形势环流特征为两高辐合型、低压环流型、副高南侧偏东气流型3种,物理量特征温度对数压力图为潜在不稳定,K指数最低为36℃,SI指数均在0℃以下;根据昆明C INRAD-CC多普勒雷达观测资料,详细分析了15次冰雹天气过程降雹前雹云的回波强度、回波高度、水平尺度、速度场及液态含水量变化,得出40 dB z回波高度在7 km,且回波顶高度在9.5 km以上,0℃上下层30 dB z回波水平尺度之比≥0.6,且随着降雹过程的来临,0℃上下层30 dB z回波水平尺度之比逐渐增大,速度场上辐合最大高度应在7 km(-10℃层)以上,VIL值逐渐增加时,预示着地面可能产生降雹过程.
15 hail weather processes appearing in Yuxi region in central of Yunnan in summer of 2002,2003 are analyzed. The conclusion is that the weather backgrounds and eireumfluence characters of hailing in Yuxi region in central of Yunnan in summer are classified as the types of the two high pressure, the eireumfluence of low pressure and the partial east current with south of auxiliary high pressure. The temperature and logarithm pressure chart of physics character has latent instability. Average exponent of K is 36 ℃ and exponent of SI is 0 ℃. The changes of the intension of echo, the altitude of echo, the level scale of echo quantity of containing water and velocity scene of the cloud of hail are researched particularly with 15 hail weather processes. It is concluded that it will emerge the process of hail in ground when the altitude of intension of 40 dBz exceeds 7 km, and the top altitude of echo exceeds 9.5 km, and the ratio of the level scale of 30 dBz echo body of the temperature layer up 0 ℃ to the one of the temperature layer below 0 ℃ is larger than 0.6. With the coming of hail,the level scale ratio is increasing gradually, the top altitude of cyclone or convergence is higher than 7 kin( the - 10 ℃ temperature layer) and, VIL increases gradually.