摘要
飞行安全一直是人们所关注的问题,飞机颠簸是飞行中常会发生的安全问题,而冷锋天气系统下运行常常会伴随着严重的颠簸,故研究区中飞机颠簸的特征和预报方法对航空安全具有重要的意义.首先采用合成分析的方法对冬季澳洲冷锋时空分布特征进行研究再对15次冷锋事件进行分析并确定出锋区的位置,绘制锋区空间结构图.将重度颠簸数据与锋区空间位置对应后得到重度颠簸点的高发区位置.进一步探寻锋区颠簸机制,绘制锋区位温度梯度图,发现重度颠簸最密集区位于位温垂直梯度大值区内,此区域内存在较强的重力波.同时,在西风急流带南侧颠簸密集区内水平流场存在较大的气旋性切变,且垂直速度的水平梯度大值区位于0值区附近,此区域内存在次级环流,冷气团与暖气团的抬升与下沉运动最强烈.流场中随着切变速度增加Richardson数减少,Reynolds增加,持续的扰动导致该区域内较强的重力波不稳定碎变,失去稳定性的重力波从而转化为能量较高的湍流导致飞机产生严重颠簸.考虑锋区内湍流形成的重力波机制,将锋生过程中的垂直运动作用加入由Ellrod基于锋生公式推导出的EI指数中,得到EI*指数并绘制颠簸预报图,经对比验证EI*指数有较好的预报效果.
This paper firstly uses the method of synthetic analysis to study the spatial and temporal distribution characteristics of the Australian cold front in winter, then analyzes 15 cold front events to determine the location of the front area, and draws a map of the spatial structure of the front area. Comparing the data of severe turbulence with the spatial position of the frontal area, the location of the high-incidence area of the severe turbulence point is obtained. It then explores the mechanism of frontal zone turbulence, draws a map of the temperature gradient of the frontal location, and finds that the densest area of severe turbulence is located in the large value area of the vertical gradient of potential temperature, and there is a strong gravity wave in this area. At the same time, there is a large anticyclonic shear in the horizontal flow field in the turbulence-intensive area on the south side of the westerly jet belt, and the large value area of the horizontal gradient of the vertical velocity is near the zero value area. There is a secondary circulation in this area. The cold air mass and the warm air mass in this area rise and fall. The sinking motion is the strongest. As the shear velocity increases in the flow field, the Richardson number decreases, and the Reynolds increases. The continuous disturbance causes the strong gravity waves in the area unstable and broken, and the unstable gravity waves are converted into higher energy. The turbulence could cause severe turbulence in the aircraft. Considering the mechanism of gravity wave formed by the turbulence in the frontal zone, the vertical motion effect in the frontogenesis process is added to the EI index derived by Ellrod based on the frontogenesis formula to obtain the EI* index and draw the turbulence forecast map. The EI* index is verified by comparison to prove its good forecasting effect.
作者
张启凡
王永忠
裴柯欣
王圣堂
ZHANG Qi-fan;WANG Yong-zhong;PEI Ke-xin;WANG Sheng-tang(School of Air Traffic Control,Civil Aviation Flight University of China,Guanghan 618300,China)
出处
《云南民族大学学报（自然科学版）》
CAS
2021年第3期290-297,共8页
Journal of Yunnan Minzu University:Natural Sciences Edition
基金
中国民用航空飞行学院科研创新基金项目(X2020-27)。
关键词
飞行安全
重度颠簸
冷锋锋区
时空分布特征
重力波
EI*指数
flight safety
severe turbulence
cold front area
temporal and spatial distribution characteristics
gravity waves
EI*index
