Luxury effect and Urban Heat Island: a reassessment in Madrid.

“Greenness is often associated with more attractive, healthful, and wealthy urban areas since vegetation increases the urban biodiversity and reduces summer temperatures. Some analyses have pointed out a relationship between neighborhood demographics and urban vegetation that has been referred to as “luxury effect” (Leong, Dunn, and Trautwein 2018) or tree gap (Visram 2021), from which wealthy residential areas benefit from greater vegetation cover and a lower intensity of the urban heat island effect. So, this contribution relates some of the urban features, derived from remote sensing, with the dynamic of the urban heat island of Madrid, and some socio-demographic parameters at census tract level, for the summers of the 2008-2017 period.

The remote sensing indices were calculated from Landsat 5 and Landsat 8 platforms (https://earthexplorer.usgs.gov/). The urban heat island of Madrid was studied using the “Climate variables for cities in Europe from 2008 to 2017” dataset, obtained from Copernicus (https://cds.climate.copernicus.eu/cdsapp#!/software/app-health-urban-heat-islands-current-climate?tab=app), combined with observed temperature data from the Spanish Meteorological Agency (AeMet) and the Regional and Local authorities (Ayuntamiento and Gobierno Regional de Madrid). Demographic data were retrieved from the Atlas de distribución de renta de los hogares (https://www.ine.es/dyngs/INEbase/es/operacion.htm?c=Estadistica_C&cid=1254736177088&menu=ultiDatos&idp=1254735976608) and the Municipality of Madrid (https://www.madrid.es/portales/munimadrid/es/Inicio/El-Ayuntamiento/Estadistica?vgnextchannel=8156e39873674210VgnVCM1000000b205a0aRCRD).

Analyses show that Madrid's UHI is particularly intense at night, while during daytime is much weaker. This can be explained by the thermal behavior of its urban periphery, which is mainly made up of agricultural areas with rainfed crops, suffering an intense daytime heating. It is also observed that the relationship between remote sensing indices and the urban temperatures varies depending on the information provided by the indices (vegetation, built-up or aquatic surfaces density) and the time of day. The "luxury effect" is not evident, as the relationship between vegetation, heat island and various sociodemographic indicators is statistically weak. As an urban space which has evolved from many decades, Madrid offers a remarkable spatial diversity in terms of income levels or demographic composition, although some risk neighborhoods can be delimited because of the coincidence of a high amount of vulnerable population (low income, senior population, migrants) and an intense urban heat island.”