4. Definitions: the different types of urban heat island

The most widespread definition of the urban heat island phenomenon is the most general. The urban heat island is the positive difference in air temperature between urbanized areas on the one hand, and rural areas on the other. However, there are several types of urban heat island .

The underground heat island is the type least studied in the scientific literature. It corresponds to a temperature difference between the ground beneath cities, including urban soils and underground building materials, on the one hand, and rural soils on the other.

The surface heat island is the temperature difference...