The Correspondence between Large Pressure Fluctuations and Runway Wind Shear: The Event on 12 December 2019 at Songshan Airport, Taipei

Abstract

In this study, the association of large pressure fluctuations (LPFs) ≥ 0.2 hPa and runway wind shear (RWS) ≥ 12 kt at the Songshan Airport in Taipei, Taiwan, during the event on 12 December 2019 with strong northeasterly winds are analyzed. The goal of the study is to demonstrate that the two phenomena exhibited close correspondence, and the former (LPFs) measured using a single barometer can be useful to detect the latter (RWS), which relies on the low-level wind-shear alert system (LLWAS) at the present time. Concentrated before 1200 UTC and especially during 0100-0800 UTC, both LPFs (52 times) and RWS (62 times) over the runway exhibited close association, and one rarely occurred more than 15–20 min apart in time from the other. Using the 2 × 2 contingency table and categorical scores, our results for LPFs and RWS to both occur at least once or five times within the same hour also suggest high accuracy rates of ≥80% and low miss rate and false alarm ratio of both < 10%, respectively. The two variables are also tested to be statistically dependent on each other to a high confidence level of 95–97.5%. Thus, using LPFs as an auxiliary or additional method to detect RWS at airports appears to be reasonable and feasible. At small and remote airports where the LLWAS is not yet available, this method also provides a good and less expensive alternative and can be helpful to the overall improvement of air traffic safety around the world.

Keywords

• runway wind shear (RWS)
• large pressure fluctuation (LPF)
• low-level wind-shear alert system (LLWAS)
• categorical statistics