Heat Waves and Human Well-Being in Madrid (Spain)

Domingo Rasilla,Alberto Martilli,Fernando Allende,Felipe Fernández

doi:10.3390/atmos10050288

Abstract

Heat waves pose additional risks to urban spaces because of the additional heat provided by urban heat islands (UHIs) as well as poorer air quality. Our study focuses on the analysis of UHIs, human thermal comfort, and air quality for the city of Madrid, Spain during heat waves. Heat wave periods are defined using the long-term records from the urban station Madrid-Retiro. Two types of UHI were studied: the canopy layer UHI (CLUHI) was evaluated using air temperature time-series from five meteorological stations; the surface UHI (SUHI) was derived from land surface temperature (LST) images from MODIS (Moderate Resolution Imaging Spectroradiometer) products. To assess human thermal comfort, the Physiological Equivalent Temperature (PET) index was applied. Air quality was analyzed from the records of two air quality networks. More frequent and longer heat waves have been observed since 1980; the nocturnal CLUHI and both the diurnal and nocturnal SUHI experience an intensification, which have led to an increasing number of tropical nights. Conversely, thermal stress is extreme by day in the city due to the lack of cooling by winds. Finally, air quality during heat waves deteriorates because of the higher than normal amount of particles arriving from Northern Africa.

Highlights

The warming of global temperatures during the last 150 years has been accompanied by an increase in the occurrence of heat waves [1,2], a trend that seems to be in close agreement with the most probable scenarios provided by climate models for the rest of the 21st century [3,4]
The objective of this study was to identify some characteristics of the heat waves that have been observed in Madrid since 1880 and to assess the urban heat island, thermal comfort, and air quality during those events
We first review the main temporal characteristics of heat waves in the Madrid metropolitan area to continue with an analysis of how heat waves affect the urban heat islands (UHIs) phenomenon

Summary

Introduction

The warming of global temperatures during the last 150 years has been accompanied by an increase in the occurrence of heat waves [1,2], a trend that seems to be in close agreement with the most probable scenarios provided by climate models for the rest of the 21st century [3,4]. Heat wave impacts are diverse and widespread (crop failures, livestock losses, disruption of transportation, spreading of wildfires, power outages), but are harmful in urban areas, due to the high population density and the urban heat island (UHI) effect, among other factors. UHI refers to a human-induced modification of the regional climate whereby the cities become warmer than their rural surroundings. The prolongation of the diurnal thermal stress into the nocturnal hours deprives the population of relief, producing serious impacts on sensitive groups [10,11,12,13]

Objectives

Results

Conclusion