飞机空中积冰的气象条件分析及数值预报试验

利用2000年3月至2005年6月山东飞机增雨作业季节,90架次飞机宏观观测资料,对飞机积冰的气象条件和积冰特征进行了分析;并利用PSU/NCAR MM5非静力数值模式,对2005年5月16日增雨作业过程进行了个例研究,在模式准确地预测出了降水的发展趋势和降水范围的基础上,用模式预报场计算的积冰指数和实际飞行观测资料进行了对比试验。结果表明,地面倒槽和冷锋,是山东飞机增雨作业季节的主要作业天气;低压倒槽出现轻度及中度以上积冰所占的比率最大,但南方气旋出现积冰的概率最高,达53.3%;MM5模式预报场计算的积冰指数和垂直上升运动场的叠加,能较好地反映最可能发生积冰的区域、时间及积冰强度,可作为确定飞机增雨作业安全飞行航线的依据。

Statistical Analysis and Numerical Prediction Experiment of Weather Conditions for Aircraft Icing

Weather conditions for airplane icing and icing characteristics are analyzed on the basis of the measurements from 90 airplane flights from March 2000 to June 2005.The PSU/NCAR MM5 model is used to replicate the process of precipitation enhancement on 16 May 2005 in Shandong,and the simulation results show that the evolvement and range of the event agree well with observation.On the basis of success simulation,a contrast experiment between the icing index from the model output and airplane measurements is conducted.The results show that reverse troughs and cold fronts on the ground are the main weather systems during the airplane precipitation enhancement season in Shandong;the greatest percentage of mild and moderate icing occurs along with surface low-pressure troughs,but the highest probability of icing is along with Southern Cyclone, up to 53.3%.The superposed field of the icing-index from MM5 model output and vertical velocity fields can be used to describe well the area,time and intensity of icing in precipitation enhancement operations.