浙北地区多普勒雷达逆风区与风廓线雷达边界层大风提前量研究

Research on the Advance Time between Doppler Radar Adverse-Wind Areas and Wind Profile Radar Boundary Layer Strong Winds in Northern Zhejiang Province

浙江地区汛期雷暴大风天气多发频发,常导致经济损失和人员伤亡。为提高短临预报水平,文章利用地面自动气象站、多普勒天气雷达、风廓线雷达资料,选取2022年浙北地区雷暴大风个例,探究了雷达逆风区与边界层大风的关系并计算了地面大风的预警提前量。结果表明:多普勒天气雷达能提前探测到中低空和边界层逆风区的发生发展,较地面大风出现有平均16.9 min和11.4 min的提前量。通过2020~2022年的典型强对流大风个例分析,多普勒雷达逆风区–风廓线雷达边界层大风–自动站地面大风三者之间能形成短临预报提前量时间链,对地面雷暴大风的短临预警有指示意义。此外,2022年7月12日发生的下击暴流事件中,多普勒雷达最低仰角探测水平风场变化不明显,但风廓线雷达探测到高空风速突然增大,早于地面大风出现时间约33 min,表明风廓线雷达有利于提高下击暴流的提前预报预警能力。

Thunderstorms and strong winds are frequent during the flood season in Zhejiang Province, which often leads to economic losses and casualties. In order to improve the level of short-term and im-minent forecasting, this article uses the data of automatic weather station, Doppler radar and wind profile radar to select a case of thunderstorm and strong wind in northern Zhejiang in 2022, explore the relationship between radar adverse-wind areas and boundary layer strong winds, and calculate the early warning advance time of ground strong wind. The results show that Doppler weather ra-dar can detect the occurrence and development of adverse-wind areas in the middle and low altitudes and boundary layers in advance, with an average advance of 16.9 minutes and 11.4 minutes compared to the appearance of strong winds on the ground. Through the analysis of typical cases of strong convective winds from 2020 to 2022, it can be concluded that the Doppler radar adverse-wind areas, boundary layer winds detected by wind profile radar, and ground strong winds can form a time chain, which has indicative significance for short-term forecasting of thunderstorm winds on the ground. In addition, during the downburst event that occurred on July 12, 2022, the Doppler radar detected no significant changes in the horizontal wind field at the lowest elevation angle. However, the wind profile radar detected a sudden increase in high-altitude wind speed about 33 minutes earlier than the appearance of strong winds on the ground, indicating that the wind profile radar is beneficial for improving the early warning and forecasting capabilities of downbursts.