Urban Heat Islands

Urban Heat Island Over 100 years, it is known that two adjacent cities are usually warmer than the surrounding area. Warm areas in the urban area, known as urban heat islands, can affect the concentration of air pollution. Urban heat islands are formed when industrial areas and urban areas develop and heat gets richer. In rural areas, most of the incoming solar energy is used to evaporate water from vegetation and soil. In the city there are few vegetation and exposed soils, most of the sun's energy is absorbed by the urban structure and asphalt.

Over the years, the existence of urban heat island has raised concern. When heat is generated and maintained in industrial areas and urban areas, urban heat islands are formed. Most of the solar energy reaching rural areas is consumed by vegetation and evaporation of moisture from the soil. In the city, the vegetation is small, the soil is exposed, and most of the solar energy is absorbed by buildings and asphalt, so the surface temperature increases. Automotive, factory, industrial and domestic air conditioners emit more heat. Therefore, the temperature in the city is usually 1 to 3 ° C higher than the temperature of the surrounding landscape. Impacts include a reduction in soil moisture and a reduction in resorption of carbon dioxide emissions.

Along with the worldwide population growth and the development of the city center, the heat generated from the human activity and impermeable surfaces leads to a climate known as Urban Heat Island (UHI). Urban heat islands are defined as closed isotherms. This usually refers to the surface (canopy) of air near the ground, which is relatively warmer than the surroundings. Usually, high temperature is recorded in the center of the central city. By changing the land cover from natural vegetation to building materials, short wave energy (heat) is absorbed during the day and stored in low albedo asphalt, concrete and glass. Distributing extra heat becomes even more difficult as it absorbs hot air in building materials and in places close to each other. In addition, excessive use of air conditioning, reduction of heat island effect, release of waste heat to the atmosphere, rise in temperature