The Study On Characteristics Of Thunderstorm In Hunan Airspace

Thunderstorm is an important weather phenomenon affecting the operation efficiency of flights in summer.Hunan Province is located in the South and mountainous.Its airspace contains many important routes.Convective activities are frequent in summer,which is easy to affect the operation of local flights.Therefore,studying the characteristics of thunderstorm activity in this area is the basic work to evaluate the airspace flow and capacity in this area.This study uses multi-source data such as airport message,lightning location data and weather radar to analyze the characteristics of thunderstorm activity in Hunan airspace.The first mock exam data of Hunan province were analyzed.The first contribution of the first mode was 57.1%,which showed the consistency of Thunderstorm in the whole area,and the contribution rate of the second mode was 8.7%.Then the key areas are selected for seasonal and diurnal variation analysis.It is found that the overall seasonal variation in mountainous areas and plain areas is consistent with the overall variation characteristics of Hunan airspace,and the lightning frequency in mountainous areas is generally higher than that in plain areas;The change curve of plain areas and eastern mountains is relatively flat,while the lightning frequency of western mountains will increase sharply in June.The diurnal variation in mountainous areas and plain areas still shows a double peak and double valley structure,but the peaks of the western mountainous areas are almost equal,while the two peaks in plain areas and eastern mountainous areas are quite different,especially in the eastern mountainous areas,the increase of lightning frequency is the largest from 10:00 to 15:00.Combined with lightning location data and Doppler radar data,the statistical relationship between total lightning frequency and echo intensity and height in Hunan is analyzed.The results show that the maximum echo top height is concentrated in 8?11km in spring,12?16km in summer,the maximum cumulative liquid water content is concentrated in 5?15kg/m~2in spring,10?25kg/m~2 in summer,the maximum basic reflectivity is concentrated in 51?56d BZ in spring and 53?57d BZ in summer.The total lightning frequency in mountainous areas and plain areas is generally located at 1?10km in the middle and lower layers.The vertical distribution of plain and eastern mountainous areas is relatively similar.Below 10km,lightning appears,and the echo intensity decreases gradually with the increase of height;With the increase of height,the uncertainty of the relationship between lightning and radar echo in the western mountainous area increases,and there are two lightning frequent centers of 43d BZ and 55d BZ at the height of 8km.Finally,through the case analysis of thunderstorm,combined with lightning activity and other products of radar echo,it can be concluded that the front cloud area of thunderstorm cloud cluster shows mesoscale band echo with uneven structure,and the rear cloud area belongs to weak echo or no echo area;Lightning activity is mainly concentrated in the strong echo area on the strip echo and near the mesoscale uneven wind field,and the stronger the echo intensity and the higher the top height,the denser the lightning activity is;In the later stage of development,sparse positive lightning is scattered on the rear edge of strong echo or the rear weak convective echo and stratiform cloud echo.