Analysis of Causes of a Severe Turbulence Event in Xiamen Airspace
LIANG Qiufeng
ZHENG Hui
SU Lei
BAO Xiaojun
HUANG Hui
Abstract：This study analyzed a severe turbulence event that occurred on June 23,2023,at an altitude of 2 700 meters within the Xiamen airspace,utilizing aircraft turbulence reports,ADS-B data from the Xiamen Air Traffic Management Station,ERA5 reanalysis data,and observations from X-band dual-polarization phased-array weather radar deployed by the Xiamen Meteorological Bureau.The findings revealed that:(1)The turbulence occurred under the influence of southwest airflow on the right side of the jet stream,characterized by abundant moisture and wind field convergence at the low level,and a weak cold center and 200 hPa divergence at the mid level.The atmospheric stratification was unstable,with high potential convective energy and small vertical wind shear.These conditions,coupled with surface convergence and uplift,were conducive to the development of convective weather,particularly pulse storms.The turbulence was located on the periphery of a region with high vertical velocity and was encircled by multiple divergences in both horizontal and vertical directions.The rotation at the low level was positive vorticity cyclonic,while at the mid and upper levels,it became anticyclonic,creating favorable conditions for the development of convective weather.(2)The direct cause of the severe turbulence was the aircraft's passage through a.rapidly developing pulse storm.Despite the convective cell's low reflectivity,the wind field within the cloud exhibited strong shear and rotation with a small spatial scale and complex airflow conditions.The vertical velocity measured and inverted by the X-band phased-array weather radar corresponded well with the aircraft's flight data,indicating that changes in cloud airflow led to severe turbulence.(3)A clear correspondence was observed between the high value areas of ZDR and strong updrafts,with sinking disturbance airflow in the rear.KDP values,affected by particle density,presented less distinct radar signatures,with high-value areas sometimes corresponding to descending airflow.(4)X-band phased-array radar shear products(convergence shear,axial shear,and range shear)effectively captured changes in the airflow of small-scale convective cells,providing a measure of early warning for the development of convective echoes.If the shear was strong,the convective cloud clusters were likely to continue developing.
Keywords：flight turbulenceX-bandphased-array weather radar products
Publication Date：2025-02-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 136-146 )