Spatiotemporal Distribution Characteristics Research of Wind Field and Wind Shear on the East Coast of Erhai Lake in the Southeast Edge of Hengduan Mountain Area

Wind profiling radar is a remote sensing device that boasts high spatiotemporal resolution and good consistency with sounding data， capable of probing the vertical distribution of atmospheric wind fields.Dali Airport， situated at the western edge of the Yunnan-Guizhou Plateau， on the southeastern rim of the Hengduan Mountains， is a typical plateau airport characterized by pronounced local circulation， where wind significantly impacts aviation safety.By statistically analyzing the vertical distribution of wind fields and the characteristics of wind shear using Dali Airport's wind profiling radar observations from 2016 to 2022， this study aims to enhance our understanding of the vertical structural features of wind fields over complex underlying surfaces and assess the impact of wind shear on aviation safety at civil airports.Key findings include： （1） Horizontal wind speeds are higher in winter and spring， with wind speed frequency contours resembling a trumpet shape （narrow below， wide above）.In summer， the contours exhibit a relatively straight and smooth S-shape， with similar wind speed distributions between the lower and upper layers.Autumn serves as a transitional period between summer and winter， necessitating attention to wind shear near 1000 meters and the impact of strong winds in winter and spring on flight safety.（2） The prevailing wind direction at higher altitudes throughout the year is westerly， while it shifts to southerly near the surface.At around 500 meters， a change in wind direction occurs with increasing altitude.Given the airport runway orientation， the impact of varying crosswind components on takeoffs and landings must be considered.（3） The mean zonal wind speed exceeds the mean meridional wind speed.Daily variations in wind fields are influenced by solar radiation， with 13:00 （UTC， the same as after） and 00:00 marking crucial time nodes for zonal wind speed changes， and 07:00 and 02:00 for meridional wind speed changes.（4） Vertical velocities are greater in spring and winter， with more dispersed frequency distributions， while they are smaller and more concentrated in summer and autumn.The frequency of downdrafts exceeds that of updrafts， exhibiting pronounced diurnal variations.（5） Spring sees a higher frequency and intensity of vertical wind shear events， with more occurrences of severe levels， followed by autumn and winter.Significant differences exist in the multi-year average frequency of wind shear across various altitude levels， with a hotspot for wind shear occurring between 840 and 900 meters.Taking 1000 meters as the boundary， notable differences are observed in wind shear indices between the upper and lower layers.