Sea‐Land Breeze Climatology in Middle‐Eastern Tunisia (2000–2020)

ABSTRACTThis study summarises the results of work conducted on the characteristics of the coastal breeze between 2000 and 2020 in central‐eastern Tunisia, and particularly in the region of Sfax where this phenomenon at mesoscale strongly impacts air quality. In a first step, this study shows from hourly weather data, given by Tunisian National Institute of Meteorology (TNIM), from five synoptic stations in central‐eastern Tunisia the characteristics of the sea and land breeze. The mean annual occurrence of the phenomenon in question ranges from 34% in Kairouan (50 km from the sea) to 63% in Sfax (6 km from the sea). It is more prevalent during the summer months and its characteristics vary depending on the latitude, distance to the sea and the coastline. Therefore, it becomes more frequent by heading south and approaching the sea where its frequency approaches 80% in July and August, as it is the case in Enfidha, Mahdia, Monastir and Sfax. The speed and duration of the sea breeze are of significant importance for meteorological stations situated in close proximity to the sea. The mean speed is approximately 4.5 m/s in winter (DJF) and 5.7 m/s in summer (JJA), with a duration of up to 11 h during the summer months. In the same season, the mean speed in Kairouan is 1.5 m/s, with an average duration of 4 h. At Cape of Mahdia, the wind rose is multidirectional, while at the other stations, the dominant direction of the sea breeze is close to perpendicular to the coastline. The location of the sea breeze front was determined by means of MSG satellite images and wind data. The study revealed that the annual mean inland of the sea breezes is 70 km, with notable variations throughout the year. The distance is 90 km during the summer months, but reduces to 33 km during the winter. Secondly, wind data from 14 automatic meteorological stations demonstrate the influence of the city and topography on the breeze in the region of Sfax. It emerges that the duration of the sea breeze is longer in cities near the coastline because of an early rise and a late sunset under the influence of the urban heat island (UHI). Moreover, in an island environment, the circulation of the coastal breeze is more impacted by the synoptic wind, as is the case in Kerkennah.