飞机积冰预报算法的研究与个例分析

Study on Prediction Method of Aircraft Icing and Case Analysis

摘要: 本文利用ERA-Interim数据从水汽条件、热力条件、动力条件三个方面分析双流机场的7次积冰个例的积冰气象条件，并通过三种积冰预报算法对该7次个例进行积冰预报，对比分析其预报结果与实报数据。研究发现，这7次积冰过程所在的积冰区域水汽含量充足，相对湿度均在60%以上，且大部分积冰区域为水汽通量散度垂直积分的负值区，有足够的水汽输送。积冰高度附近为逆温层或等温层，温度范围在−10˚C至0˚C之间。动力条件方面，积冰区域位于正涡度区，有气旋性涡旋环流。低层大气辐合，高层辐散，且积冰区域有垂直速度为−0.1 Pa/s至−0.5 Pa/s之间的垂直上升运动，云中的上升气流能够促进液态水含量的增加和维持，从而有利于积冰形成。在利用飞机积冰预报算法对这7次飞机积冰过程进行有无积冰以及积冰强度的预报中，Ic指数法的预报准确率均为最高，分别为100%和71.43%。

Abstract: This study uses ERA-Interim data to analyze the physical field of seven aircraft icing cases of Shuangliu International Airport from three aspects: thermal condition, water vapor condition and dynamic condition. Using three icing prediction methods to predict these aircraft icing cases, and the predicted results and measured data were compared statistically. According to the analysis, the relative humidity is above 60%, the water vapor content in the icing area is sufficient. Most of the icing processes are located in the negative region of vertical integration of water vapor flux divergence, with sufficient water vapor import. The temperature of the icing height ranges between −10˚C to 0˚C, and there is a thermal inversion layer or isothermal layer near the icing height. In terms of dynamic conditions, the icing region is a positive relative vorticity region, the atmosphere of icing region has a cyclonic vortex circulation. In addition, the atmosphere is convergence at a low-level, but divergence at a high-level. The icing area has vertical velocity of −0.1 Pa/s to −0.5 Pa/s, this updraft in the cloud can maintain and increase the liquid water content, which will make the liquid water gather and beneficial to the formation of aircraft icing. Finally, the prediction accuracies of the Ic index method to the presence and strength of aircraft icing both are the highest, 100% and 71.43% respectively.