Air-Traffic Restrictions at the Madeira International Airport Due to Adverse Winds: Links to Synoptic-Scale Patterns and Orographic Effects

Abstract

The Madeira International Airport (MIA) lies on the island’s south-eastern coast and it is known to be exposed to wind hazards. A link between these adverse winds at MIA and the synoptic-scale circulation is established using a weather type (WT) classification. From April to September (summer period), five WTs prevail, cumulatively representing nearly 70% of days. These WTs reflect the presence of well-established Azores high, with some variations on location and strength. Although with a low frequency of occurrence (<5%), this anticyclone occasionally strengthens and extends towards Iberia, inducing anomalously strong NNE/NE up to 3–5 km over Madeira. The most severe and longer-lasting wind conditions at the MIA, with a higher frequency of gusts above 35 kt, are driven by this synoptic-scale pattern and are more common in summer. An episode of adverse winds at the MIA is analysed, illustrating the occurrence of upstream stagnation, flow splitting, and lee wake formation. The upstream conditions include a low-level inversion, strong NNE/NE winds near and above the inversion and a Froude number less than 1. The AROME (Application of Research to Operations at Mesoscale) model predicted the occurrence of downslope winds, in association with a large-amplitude mountain wave. At this time, the strongest wind gusts were registered and one aircraft executed a missed approach. The wind regime in different places of the island suggests that these conditions are relatively frequent, mostly in summer. Finally, objective verification of AROME wind forecast, for a three-year period and from June to August, is discussed.

Impact of Flash Flood Events on the Coastal Waters Around Madeira Island: The “Land Mass Effect”

“…Concerning wind, comparison of model results with in situ measurements demonstrates that the model represents the main spatial and temporal variability of the wind speed (Figure 5, right panels). Correlation coefficients (mostly ranged between 0.7 and 0.9; Table 2) are similar or higher than those reported in previous studies (Pullen et al, 2017b;Alves et al, 2020;Belo-Pereira and Santos, 2020). However, RMSE are higher than those reported by Alves et al (2020).…”

“…Snapshots of surface maps for the 2nd of February 2010 flash flood event are shown in Figures 8A-D. The wind field clearly reflects the orographic effects on the lower atmospheric level, frequently detected in Madeira Island (Couvelard et al, 2012;Caldeira and Tomé, 2013;Caldeira et al, 2014;Pullen et al, 2017b;Caldeira, 2018;Alves et al, 2020Alves et al, , 2021Belo-Pereira and Santos, 2020). This pattern is particularly evident at 06:00 and 12:00 UTC, when moderate northeasterly winds (∼15 m s −1 ) intercepted the island's topography, inducing an intensification of the wind at the eastern and western flanks, and a deceleration in the southern (wake) side (<5 m s −1 ; Figures 8A,B).…”

“…Given its location, at the eastern boundary of the North Atlantic Subtropical Gyre, the climate is mainly controlled by the Azores subtropical highpressure system interacting with its topography. The high terrain acts as a perpendicular barrier to the prevailing northeastern trade winds (Caldeira et al, 2002;Prada et al, 2009;Gorricha et al, 2012;Alves et al, 2020;Belo-Pereira and Santos, 2020). As a result, many microclimates form within the island (Espinosa et al, 2021).…”

“…These data were provided by the Portuguese Institute for Sea and Atmosphere (IPMA), with data available since 2007. The model simulations were quantitatively assessed based on statistical analysis (correlation coefficient-r, root-mean-square error-RMSE, and bias; Table 2) widely used to evaluate atmospheric model performance (e.g., Alves et al, 2020;Belo-Pereira and Santos, 2020). Additionally, precipitation data for 9 meteorological stations were obtained from the Portuguese water resources database (SNIRH) 1 to be used in the long-term analysis of SPM and Chla (shown in Figures 1A,B).…”

A computer vision approach for satellite-driven wind nowcasting over complex terrains

“…Accurate forecasting of wind speed and direction is challenging, especially in areas with complex topography such as Madeira Island, where the terrain significantly affects weather patterns, with greater relevance at the Madeira International Airport, Portugal [1,2] which, from this point forward, will be designated by its International Civil Aviation Organization code, LPMA [3]. In aviation, precise wind forecasting is crucial for ensuring operational safety, as wind parameters are key factors contributing to weather-related aviation incidents [4].…”