Smart Monitoring of Urban Heat Islands in Algiers, Algeria: A Hybrid Approach Using Mobile Sensors and Satellite Data

Abstract

Due to fast urbanization, urban heat islands (UHIs) raise urban temperatures and have been widely studied/monitored for their implications on quality of life, public health, and energy use under climate change. This article introduces a smart monitoring approach from studying the UHIs in Algiers, Algeria, a densely populated Mediterranean city sensitive to extreme heat events like the heat wave of July 2019. Two vehicle-mounted prototypes measuring air temperature and humidity were deployed to collect data, complemented by three satellite images for land surface temperature (LST) analysis and mapping. Data processing included matching mobile measurements with satellite overpasses, computing land surface temperature (LST) using a standard algorithm, and mapping urban heat islands (UHIs) with the help of geographic information systems (GIS) interpolation. The results demonstrated an important linear relationship between sensor air temperature and LST in Algiers (R2 = 0.752), where discrepancies between sensor air temperature and LST revealed the complexities of the UHI phenomenon. The study proves that smart monitoring is possible, but also shows that the methods must be improved in order to provide accurate and scalable monitoring. It set the stage for dynamic visualization on a web server, which facilitated real-time heat wave alerts. However, constraints of limited sensor coverage underuse of humidity data, and vehicle-related biases limit the scalability of this approach. This approach enhances urban heat island (UHI) characterization over conventional approaches, providing a flexible platform for climate adaptation initiatives in cities, one that can be extended beyond UHI following optimization.