Lightning Characteristics Over Shenzhen Area Induced By Tropical Cyclones

This paper studies the characteristics and laws of lightning in Shenzhen under the influence of tropical cyclones.Based on the historical data of tropical cyclones in the Northwest Pacific from 2012 to 2019,the tropical cyclones within 1000 km from Shenzhen National Meteorological basic station from 2012 to 2019 are selected and grouped according to the intensity level of tropical cyclones.Using the observation data of lightning,temperature and precipitation in Shenzhen in the same period,this paper studies the temporal and spatial distribution characteristics of lightning and the correlation between other meteorological elements and lightning in Shenzhen under different distances and azimuth angles of different levels of tropical cyclones.Finally,the background field of typical typhoon niebert is studied by using era5 reanalysis data.The study found that under the influence of tropical cyclones,lightning activities in Shenzhen vary greatly from year to year,with the most in 2016 and the least in 2014,with a difference of nearly 10 times.Lightning activities in Shenzhen are the most active in July and August,accounting for 81% of the whole year.When the tropical cyclone of any level is within 400 km from Shenzhen,the temperature in Shenzhen is low,which is not easy to cause lightning impact on Shenzhen;When it is more than 400 km away from Shenzhen,that is,Shenzhen is in the peripheral rain belt of tropical cyclone.At this time,the temperature in Shenzhen is high,and the impact on lightning in Shenzhen tends to increase.The coordinate system is established with the location of the National Meteorological basic station in Shenzhen as the coordinate origin.Tropical storm(TS)has the greatest impact on lightning activities in Shenzhen in the northeast quadrant,southwest quadrant and Southeast quadrant,and tropical depression(TD)has the greatest impact in the northwest quadrant.Generally speaking,there is no obvious correlation between the intensity of lightning activity in Shenzhen under the influence of tropical cyclones and the grade of tropical cyclones.It is not that the stronger the grade,the more active the lightning activity in Shenzhen;When tropical cyclones are located in the east of Shenzhen,they cause more lightning than when they are located in the west of Shenzhen.Especially when TS is located in Fujian and 400-600 km away from Shenzhen,it is very easy to bring lightning impact to Shenzhen.This paper can provide scientific and technological reference for the work of Taiwan defense and disaster reduction in Shenzhen,and has important practical significance for the economic development of Shenzhen.