Complex winds, complex comfort: the impacts of sea breezes on coastal heat stress

Sea and land breezes (SLB) affect air temperature, humidity, wind, and cloudiness in coastal areas. These local wind patterns are also the primary environmental factors that determine human thermal comfort - or lack thereof - which results in heat stress. We formulated a novel sea breeze identification method that combines changes in a comfort-related index with meteorological-sensitive criteria. In this presentation the method is illustrated.

We describe an application of the method to a set of quality-controlled observations from a coastal station near Nice, France and its successful identification of 590 sea breeze events, occurring on 54% of summer days, during 31 summer seasons from 1993 to 2023. We also demonstrate how the method can be used to assess whether heat stress is alleviated or exacerbated in the context of SLB. We found, for instance, that most of the events are linked to increases in humidity and wind speed, and offer heat relief by encouraging the body's evaporative cooling at their onset, which is typically in the morning. In addition, we provide a characterisation of those events associated with heat aggravation.

The presentation will discuss the findings in detail and highlight a more sophisticated understanding of heat stress in regions impacted by local winds.