Wind-waves in the coast of mainland Portugal induced by post-tropical storms

Abstract

In this short communication paper, we investigate the characteristics of wind-waves in Portugal mainland coast induced by post-tropical storms. Six major Atlantic hurricane events that occurred between 2012 and 2019 are studied: Rafael (2012), Joaquin (2015), Ophelia (2017), Leslie and Michael (2018), and Lorenzo (2019). None of these events has made landfall as a hurricane or tropical storm in mainland Portugal. However, Leslie and Ophelia have undergone extratropical transition close to mainland Portugal. We use wave buoy data at three different locations offshore mainland Portugal to characterize wind-waves during the events. The wind-waves here studied reached the coast in October. When compared with the dominant Northern Hemisphere winter wind-wave storms (December to March), the wind-waves here studied presented relatively mild wave conditions (maximum significant wave heights up to 5 m) that barely exceed wind-wave storm thresholds. Nevertheless, these wind-waves presented high mean direction variability, and induced high peak wave periods (up to 18 s).