Analysis of Environmental Parameter Characteristics of Severe Thunderstorm Weather at Beijing Capital International Airport

Wang Yidan; Hu Min; Zhang Lina

doi:10.16765/j.cnki.1673-7148.2025.01.004

Abstract：Based on observation data at Beijing Capital International Airport from 2019 to 2023,the severe thunderstorms occurring in the airport are classified into five types,including thunderstorm with heavy rainfall process,thunderstorm gale process,thunderstorm gale with heavy rainfall process,mixed convective thunderstorm process,and hail process.The temporal distribution characteristics of these severe thunderstorms are analyzed.Based on the data from Beijing Sounding Station,the thermal and dynamic pa-rameters of the environment atmosphere in the first four types of severe thunderstorms are calculated,and the characteristics of the environmental parameters are displayed in the form of box plots.The results show that Beijing Capital International Airport has had a total of 49 days of severe thunderstorm weather over the past five years,dominated by the thunderstorm gale and thunderstorm with heavy rainfall process(77.5%).Severe thunderstorms mainly occur from May to August,peaking in July.Most of severe thun-derstorm events occur from afternoon to early night.However,during the thunderstorm with heavy rainfall processes,thunderstorms occur most frequently in the early morning,followed by in the evening.Thunder-storm gales never appear in early morning.The number of thunderstorms decreases as the duration increa-ses.Thunderstorms accompanied by heavy rainfall typically last for more than two hours.The box plots of environmental parameters reveal that during the thunderstorm with heavy rainfall processes,the average value of CAPE is moderate,the average value of DCAPE is minimum,and the average value of K index is maximum.The average values of △T700 hPa-500 hPa and △T850 hPa-500 hPa are the minimum and close to the moist adiabatic lapse rate with weak vertical wind shear.The HDBZ is the highest,with the lowest LCL and CCL.There are warm and moist air in the middle-lower layers with substantial saturation depth.During the thunderstorm gale processes,the mean CAPE value is the smallest,but the CIN value is the largest.The mean value of K index is the smallest while the mean value of LI index is the largest.The average values of △T700 hPa-500 hPa and △T850 hPa-500 hPa are the highest,exceeding the dry adiabatic lapse rate with moderate vertical wind shear.The average values of CCL is also the highest,and the average specific humidity in the middle and lower layers is the lowest with the dry air.During the thunderstorm gale with heavy rainfall processes,the average values of CAPE and DCAPE are moderate.The average value of K index is higher,while the average values of LI,LCL and CCL are lower.Average specific humidity below 925 hPa is higher,but that at 500 hPa is the driest.In the mixed convective thunderstorm processes,the average val-ues of CAPE and DCAPE are the highest,the average value of LI is the lowest,and the average LCL is the highest with HDBZ,HWBZ,and H-20 being higher and concentrated within a small range,respectively.The surface temperature is the highest,with a higher specific humidity below 700 hPa and a very dry layer at 500 hPa.According to the characteristics of different convective parameters,environmental parameter thresholds for different types of severe thunderstorm weather are summarized by 25%or 75%percentile values.This is of significance in guiding the forecasting and warning of severe thunderstorms at Beijing Capital International Airport.