Characterization of Surface Urban Heat Island in the Greater Toronto Area Using Thermal Infrared Satellite Imagery

Abstract

For the past decades, there have been increasing concerns about urban environmental degradation, especially under the circumstance of urbanization. This thesis compares the trends between air temperature and surface temperature, and characterizes spatial distribution and connection with relevant urban characteristics, in the Greater Toronto Area (GTA) of Ontario in the context of surface urban heat island (SUHI). The trends in annual and seasonal temperature were investigated in the GTA from 1984 to 2014. The Mann-Kendall test is used to assess the significance of the trends and the Theil-Sen slope estimator is used to identify their magnitude. Statistically significant increasing trends for annual mean temperatures are observed mainly at the urban and suburban stations. The temperature variation is consistent with the pace of urbanization, however, the choice of the stations is vital in the estimation of the UHI intensity which can overestimate or underestimate the prediction. A local scale investigation was continued by applying Landsat and ASTER thermal-band images in order to characterize SUHI intensity in the study area. Results show that strong SUHI phenomenon is mainly observed at downtown Toronto and industrial areas. As the enhancement of urbanization, tracking and monitoring of SUHI is imperative to understand the potential impact of the increased heat waves.