丽江机场地面大风时间变化特征及形成机制分析
网络出版日期: 2025-05-20
基金资助
云南省重点研发计划项目(202203AC100006);第二次青藏高原综合科学考察研究项目(2019QZKK010408)
Temporal Characteristics and Formation Mechanism Analysis of Surface Gales at Lijiang Airport
Online published: 2025-05-20
随着我国航空运输业的快速发展,高原机场的特殊气象条件对飞行安全的影响日益凸显。其中,大风是影响飞行安全与效率的核心要素。利用 2021-2023年丽江机场地面观测资料和 ERA5再分析资料,对丽江机场地面大风时间变化特征及其形成机制进行分析。结果表明:(1)丽江机场地面大风主要发生在每年1-4月的干季,且集中在每日05:00-11:00(世界时,下同),其中07:00-09:00为大风高发时段,占大风事件总数的 54%。(2)大风事件的发生通常伴随风向的显著转换,特别是在 03:00前后,风向由偏北风迅速转为偏南风,风速在此后显著增加。地面大风过程中,尽管正侧风风速未达到限制飞机起降的标准,但部分极端大风事件中正侧风风速超过10 m·s-1,仍可能对飞行安全构成威胁。(3)物理量场和环流背景分析表明,午后热低压驱动地面变压风辐合,使得垂直方向对流活动增强破坏了低层大气的稳定层结,进而通过湍流混合作用诱发500 hPa西风急流动量下传形成地面大风。此外,寒潮爆发前北方冷涡对500 hPa西风气流的增速进一步增强了地面大风。通过分析极端地面大风个例的热力与动力驱动机制,构建地面大风概念模型,为进一步提高大风预警精度及飞行安全保障能力提供理论依据。(4)风切变特征表现出明显的时空规律:地面风增速阶段 450~550 hPa风切变增强,550~650 hPa风切变减弱;地面风减速阶段 450~550 hPa风切变减弱,550~650 hPa风切变增强。这一变化特征为风切变的预警提供了重要参考。
赵元枫, 肖天贵, 魏 翔, 时一文 . 丽江机场地面大风时间变化特征及形成机制分析 [J]. 高原气象, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00063
With the rapid development of China's air transportation,the special meteorological conditions of plateau airports have increasingly highlighted the impact on flight safety. In particular,gales represent a critical meteorological factor that significantly impact both flight safety and operational efficiency in aviation systems. Utilizing ground observation data of Lijiang Airport from 2021 to 2023,along with ERA5 reanalysis data,we con‐ ducted an analysis on the temporal characteristics and formation mechanisms of surface gales at Lijiang Airport. The results show:(1)surface gales predominantly occur during the dry season,which spans from January to April each year. These gales tend to be concentrated between 05:00(UTC,the same as after)and 11:00 am on a daily basis. Notably,the peak period for strong winds occurs between 07:00 and 09:00 am,accounting for 54% of the total number of gales events.(2)The occurrence of gale events was usually accompanied by a significant change in wind direction,especially around 03:00 when the wind direction rapidly shifts from northerly to southerly,and the wind speed increases significantly thereafter. Therefore,airports should be prepared for run‐ way switching before 03:00 am to avoid overshooting the tailwind due to sudden changes in wind direction, which would affect flight safety. During surface gales,even though the positive crosswind speed might not reach the threshold that restricts aircraft takeoff and landing,some extreme events,where the positive crosswind speed exceeds 10 m·s-1,could still pose a threat to flight safety.(3)The analysis of physical quantity and circulation background fields revealed that the convergence of variable pressure winds,driven by the afternoon thermal lows,enhanced the vertical convective activity and destroyed the stable laminar knots in the lower atmosphere, and then induced the downward transmission of 500 hPa westerly jet momentum to form the surface gale through turbulent mixing. Furthermore,prior to the outbreak of the cold wave,the northern cold vortex accelerated the 500 hPa westerly airflow,further intensifying the surface gales. By analyzing the thermal and dynamic driving mechanisms of extreme surface gales,we had constructed a conceptual model of surface gales. This model pro‐ vides a theoretical foundation for further enhancing the accuracy of wind warnings and improving flight safety assurance capabilities.(4)The wind shear characteristics exhibit distinct spatiotemporal patterns:during the phase of decreasing surface wind speed,wind shear weakens at 450~550 hPa while strengthening at 550~650 hPa. This variable feature provides an important reference for early warning of wind shear.
Key words:
Lijiang Airport; surface gales; thermal low; momentum transportation
/
〈 |
|
〉 |