滇南冰雹的预报预警方法研究

利用普洱市探空资料、CIND3830-CC新一代天气雷达资料、地面观测资料,对2004—2011年滇南普洱、西双版纳冰雹天气过程进行统计分析,总结出冰雹4个预报指标:(1)当单体回波满足冰雹云的初始特征和发展阶段特征时,可预报未来出现冰雹的可能较大,预报提前60 min以内;(2)当回波的组合反射率≥55 dBz、宽度≥12.0 km、梯度≥15 dBz·km~(-1)、H_(45 dBz)≥7.5 km、2—5月H_(45 dBz)-H_0≥3.1 km且H_(45 dBz)-H_(-20)≥-0.5 km、6-8月H_(45 dBz)-H_0≥2.0 km且H_(45 dBz)-H_(-20)≥-1.2km、VIL≥30 kg·m~(-2)、D_(VIL)≥3.0 g·m~(-3)时,预报有冰雹发生,预报提前12~102 min;(3)当回波具有弱切变特征、45 dBz回波顶高≥7.5 km、2—5月H_(45 dBz)-H_0≥3.1 km且H_(45 dBz)-H_(-20)≥-0.5 km、6—8月H_(45 dBz)-H_0≥2.0 km且H_(45 dBz)-H_(-20)≥-1.2 km时,可预报有冰雹出现,预报提前18~54 min;(4)若除去飑线和下击暴流回波,当回波的VIL≥30 kg·m~(-2)、D_(VIL)≥3.0 g·m~(-3)时,可预报有冰雹出现,预报提前12~54 min。此外,还总结了冰雹云的生命期特征等,并利用2012年发生的冰雹天气过程检验了预报指标。

Study of the Method for Hail Forecasting and Warning in Southern Yunnan

Based on the verification and evaluation of the quality of CFSR (Climate Forecast System Reanalysis) cloud amount reanalysis data by satellite remote sensing data MODIS, we analyze the average distribution of global total and low, middle, high cloud amount from 1979 to 2009 as well as the cloud amount variation along the latitude. Also, by using empirical mode decomposition (EMD) method, we analyze the change trend of each cloud amount in the recent 30 years. The results show that: (1) the global average total cloud amount in recent 30 years is about 59%, the global total and low, middle, high cloud amounts have obvious zonal distribution characteristics, and there are 3 peak value zones and 3 low value zones for the total cloud amount. (2) The difference of land sea distribution for low cloud amount is obvious and the amount of low cloud over the land is significantly lower than that over the ocean. Except for the two polar regions, the amount of low cloud in the Southern Hemisphere is more than that of the corresponding latitudes in the Northern Hemisphere; the locations of maximum and minimum of high cloud amount are between the mid low latitudes (30°) of Southern, and Northern Hemispheres respectively. In addition, the low value center mainly distributes in the eastern ocean. (3) The variation of total cloud amount is in an increasing trend, and it is specificly displayed as skyrocketed after a slightly decrease with the time. Its jump point year is around 1993, after which total cloud amount increases significantly. Low and high cloud amounts show a decreasing trend, in contrast, middle cloud amount is decreasing. Low cloud amount increases the most by nearly 2% while the change of high cloud amount is smaller.