Temporal Characteristics and Formation Mechanism Analysis of Surface Gales at Lijiang Airport
Online published: 2025-05-20
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
ZHAO Yuanfeng, XIAO Tiangui, WEI Xiang, SHI Yiwen . Temporal Characteristics and Formation Mechanism Analysis of Surface Gales at Lijiang Airport [J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00063
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