Temporal And Spatial Characteristics Of Aircraft Icing High Incidence Areas In China And Its Meteorological Characteristics

In recent years,aircraft icing incidents occur frequently in China,and the impact of icing on the flight safety of civil aviation in China is becoming more and more obvious.Using multisource observation data and quantitative analysis methods to analyze the temporal and spatial characteristics of potential high incidence areas of ice accumulation in China and explain its meteorological causes can strengthen the understanding of China's ice accumulation meteorological environment and reduce its harm to civil aviation flight.Firstly,the temporal and spatial characteristics of China's ice accumulation high incidence areas are statistically analyzed by using the aircraft ice accumulation report data for many years.The spatial characteristics are shown in two centers: one is the area from Eastern Sichuan to Chongqing,and the other is the area along the Yellow Sea centered on Shanghai,which is highly concentrated at 700 h Pa.Its seasonal characteristics are the most obvious in winter,and the daily variation is the greatest at 02 o'clock.Therefore,for the winter icing environment,four icing indexes are calculated by using the reanalysis data and satellite data in recent 10 years to verify the existence of the above two centers respectively.For these two ice accumulation high incidence areas,the meteorological characteristics of the formation of ice accumulation high incidence areas are analyzed by synthetic analysis method.The results show that:(1)under the action of the guiding air flow in the middle and upper troposphere,the cold advection of 700 h Pa from north to south in northern China reaches the line of 30 to 35 degrees north latitude,which makes the temperature near minus 10 degrees from Eastern Sichuan to the Yangtze River Delta,providing a suitable low-temperature environment for aircraft icing;(2)The water vapor collected from the south of China and the East China Sea brings sufficient water vapor to the above areas and provides water vapor conditions for ice deposition;(3)Through the difference analysis of the combination of high and low values of ice accretion index,it is found that the key to the strength of ice accretion potential in winter is the weather situation of high in the West and low in the East in northern China.When the weather situation is strong,the cold advection is strong,which makes the multiple centers of ice accretion in winter significant.On the contrary,the cold advection is weak,and ice accretion is difficult to form.(4)the difference between the two ice accumulation centers is different from that in the eastern part of the Shanghai center.Then,a case study is carried out by using the high-resolution mesoscale numerical model to further study the meteorological characteristics of icing in China.Based on the ice deposition event of Beidahuang navigation on March 1,2021,the atmospheric circulation situation,temperature conditions,water vapor transport,local circulation and atmospheric stability in the incident area are analyzed by using station and sounding observation data.It is found that this event is mainly provided with low temperature conditions by a strong cold air southward,and water vapor conditions are provided by the low-level southerly air flow combined with the Northeast air flow on the west side of the extratropical cyclone.Finally,an ice accumulation area is formed at the height of 500 h Pa under the action of the vertical circulation.Combined with the model output results,under the appropriate temperature and humidity conditions,the high value area of liquid water content and the low value area of ice water content correspond to the high value area of ice accumulation index,that is,the meteorological environment of the day is conducive to the formation of supercooled water and the formation of ice accumulation environment.Through the above analysis,this thesis systematically describes the temporal and spatial characteristics of China's ice accumulation high incidence areas,discusses the meteorological characteristics of their formation,and verifies the role of large temperature and wet conditions on the ice accumulation environment combined with a case analysis,which has a certain reference role in preventing the risk of ice accumulation risk.thesis...