The Impact of Climate Change on the Dynamics of the Urban Thermal Environment: The Case Study of the Touristic Area of Porto, Portugal

Urban Heat Island (UHI), tends to exacerbate existing differences between urban and rural areas, with the difference between the temperatures in the city and nearby rural areas depending mainly on the city’s population. The UHI is generally quantified using Air Temperature (AT), although Remote Sensing data can also be used to provide values for Land Surface Temperature (LST) throughout the entire study area. The aim of this current chapter is to identify the primary critical areas of UHI, taking into consideration the issues it poses to human health. The UHIair intensity was analyzed at 37 points in the Porto Metropolitan Area. The estimation of LST allowed us to identify the spatial patterns of this variable, as well as the most and least critical areas with the highest intensity of Surface Urban Heat Island (UHIsurf) for the period between 2005 and 2018. Then, some criteria were parameterized to define the Air Urban Heat Island (UHIair). A thermohygrometer and an anemometer were used to define measurement points for AT, relative humidity (RH%) and wind speed (WS) along a transept that crosses the city of Porto. The survey period was July–August 2019, December–February 2020, and July–August 2020. The area with the highest average intensity of the UHI corresponds to the central core of Porto, where São Bento railway station and Avenida dos Aliados are located, areas with a high volume of motor vehicles and greater passenger traffic. The results of the present study serve as an indicator for the improvement of thermal comfort in areas with high recreational and leisure value (or potential) in the Porto Metropolitan Area. Finally, some measures have been developed aimed at improving the comfort of those who visit these spaces in the city, taking into account a fundamental condition for the use of urban space—the relationship between society and nature.