Caracterización de la isla de calor urbana superficial en la ciudad de Cuenca mediante imágenes satelitales

Abstract

Expansion and uncontrolled urban development have greatly altered the structure of land cover on a global scale. Drastic change of land use causes important secondary effects in the processes of energy balance on the Earth’s surface. Consequently, increasing rates of impermeable surfaces have given place to abnormal patterns of land surface temperature (LST). Areas with relatively high urbanization rates, such as densely populated cities, will probably be more vulnerable to non-desirable impacts of LST. The attractive nature of developed cities, due to potentially high life comfort in terms of transportation, recreation and industrialization, is the main factor that triggers fluctuations in LST values. The formation of surface urban heat islands (SUHI) is closely related with LST patterns and with land use structure. It is important to keep in mind that surface urban heat islands is one of the most common impacts derived from the process of urbanization. The unplanned expansion, mostly of impermeable surfaces can potentially increase the possibility of SUHI phenomenon to happen. Remote sensing technology is a valuable resource for the determination and quantification of the SUHI effect in a determined area. In this study, temporal evaluation of SUHI effect in the city of Cuenca is investigated. The goal of this study is to investigate surface urban heat island as a function of land surface temperature estimated from band 10 of the thermal infrared sensor (TIRS) of Landsat-8 satellite, for the period between 2013 and 2017. The results confirm the existence of a SUHI effect in the city, with variable intensities within specific locations; El Sagrario, Cañaribamba, San Blas, Gil Ramírez, Totoracocha and Sucre are the main areas that are being negatively affected by the consequences of heat islands. These areas have surfaces with the presence of SUHI in more than 50% of their territory, and they present average values of LST, between 34.28 and 35.97 °C. Additionally, the results showed that the average values of LST in the urban area were at least 3.83 to 4.87 °C higher than in undeveloped areas. Also, the positive correlation between LST and NDBI showed an amplifying effect of SUHI magnitude in developed locations, while areas with vegetation predominance attenuated the SUHI effect. On the other hand, urban centers grouped in some parts of the city received the worst ecological evaluation index. Finally, it is indispensable to mention that the adoption of measures to guide urban planning is a necessary alternative to mitigate the effect of heat islands, and to provide thermal comfort in urban zones, thus guaranteeing the quality of life of Cuenca’s population.