Wave Climate Variability along the Coastlines of Senegal over the Last Four Decades

Abstract

Knowledge of wave climate is essential for efficient management of the world’s coastal areas. Senegal is a relevant case, given its high coastal vulnerability to energetic wave conditions. This study investigates wave climates along the coastal zone of Senegal based on a new high-resolution hindcast covering the period 1980–2021. This study evaluates the average, seasonal, and extreme values for the significant wave heights (Hs), periods (Tm02/Tp), and mean directions (DIR). In boreal winter, the wave climate is dominated by swells coming from the North-Atlantic lows. In contrast, in boreal summer, the Southern Coast (from Dakar to Casamance) is exposed to swells generated in the South Atlantic Ocean. Throughout their refraction around the Dakar Peninsula, NW swells rotate by ~100° from NW to SW, while their Hs is roughly halved when reaching the Southern Coast of Senegal. Over the studied period, trends in Hs are weak (~0.6 cm.decade−1) on the Northern Coast and double on the Southern Coast (~1.2 cm.decade−1), mostly due to an increase during boreal summer (2 cm.decade−1). The wave periods show weak trends (~0.05 s.decade−1), and DIRs show weak counterclockwise rotation (−1°.decade−1). These trends are explained by the main climate modes of the Atlantic Ocean (NAO/EA during winter, SAM during summer) and are important for future research and long-term monitoring of the Senegalese Coast.