Statistical characteristics of near-surface winds at Capital International Airport of Beijing

This work studies the seasonal wind characteristics and the feature of the wind factors at Beijing Capital International Airport using the historical hourly wind observation of 10-min average data at 10 m altitude wind data collected by Automated Weather Observing System (AWOS) from January 1,2000 to December 31,2022.Results show that the wind direction is mainly affected by VRB (variable wind direction),and then followed by north wind (350°-10°),however,their annual average wind speeds were not significant.The annual average wind speed is the highest between 260°-340°,and is followed by the range of 170°- 230°.The average monthly wind speed is highest in April and lowest from July to September.The average wind speed in April is mostly between 4-6 m·s^-1,and the highest occurred in December when the wind speed was above 6 m·s^-1; the average wind speed in summer often occurs between 1 and 3 m·s^-1.The diurnal variation of wind direction is significant,with more north wind at night and in the morning,and south wind in the afternoon.However,the daily variation of wind direction varies from month to month.In winter,the wind turns later,mostly at 13:00,and in spring and summer,it turns earlier,usually between 10:00 and 11:00.The frequency of gale has significant seasonal differences,with winter and spring occurring approximately twice as frequently as in summer.In the middle troposphere,owing to the intrusion of cold dry air from the mid-high latitudes,the sinking air ahead of the ridge creates an anticyclonic cold high at the surface.The aforementioned circulation features are the strongest in winter and the weakest in spring.This study contributes to a deeper comprehension of the fine-scale spatiotemporal patterns of near-surface local wind fields within complex terrains,and can offer crucial background clues for airport operations and small-scale mountainous meteorological monitoring and forecasting.