Assessing Heatwaves and Their Association with North African Dust Intrusions in the Algarve (Portugal)

• Main Authors: Raquel Fernandes, Marcelo Fragoso
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Atmosphere
• Subjects: atmospheric patterns; cluster analysis; <i>Excess Heat Factor</i>; PM₁₀; Saharan dust events
• Online Access: https://www.mdpi.com/2073-4433/12/9/1090

Heatwaves are an extreme meteorological event in which affected populations may also be exposed to deteriorated air quality conditions due to the increase in air pollutant concentrations, such as PM₁₀ (particulate matter < 10 µg/m³). In order to identify heatwaves (1973–2019) in the region of Faro (Algarve) during the hot season (April–September), the <i>Excess Heat Factor</i> (EHF) index was applied. The Mann–Kendall test revealed an upward trend in three heatwave metrics in Faro, and the trend of accumulated heat load (EHF load) was also positive as would be expected, but its signal was not statistically significant. An inventory of North African dust events (2006–2019) was made, and their simultaneous occurrence with heatwaves was assessed, pointing to only 20% of dust events of the Sahara occurring simultaneously with heatwave days. A cluster analysis was conducted on daily geopotential height fields at 850 hPa level over the 2006–2019 period, and four distinct patterns were identified as the most prominent synoptic circulations promoting both heatwave conditions and North African dust over the Algarve.