Albedo

Albedo is the fraction of Sun’s radiation reflected from a surface. Albedo varies depending on the amount of cloud cover, the angle of the sun, the particle matter in the air and the surface area (Lutgens, Tarbuck, Tasa, 2011).Thus a higher albedo indicates a surface that absorbs less heat, and remains cooler. There are several factors that cause higher temperatures in urban area like dark rooftops, dark asphalt surfaces, and more buildings with more emitted heat from air conditioners and furnaces and denser traffic which cause elevated emissions of air pollutants. Dark roofs and dark asphalt surfaces have much lower albedos than rural areas, and this causes a buildup of heat in cities during the summer months and because the heat absorbed by the paved surfaces continue to radiate heat during the night. This effect creates a higher average temperature. The same effect causes a smaller daily temperature range in urban areas. These factors combined the low albedo surfaces and the human activities in urban areas create the heat island effect. This is an effect where the average temperature of an urban area is higher than nearby rural areas.

The other factors that might affect the temperature differences between the two settings are water vapor in the air, the aerosols, ozone depletion. The water vapor in the air can affect temperatures by absorbing heat energy given off the Earth (Lutgens et al, 2011). Another factor that might affect temperatures is aerosols which can absorbs or reflect in coming radiation (Lutgens et al, 2011). Ozone depletion is the final factor that might affect temperatures because the ozone filters out UV radiation from the sun, ozone depletion can cause changes in temperature.

Lutgens, F., Tarbuck, E., Tasa, D. (2011). Foundations of Earth Science. (6th ed). New Jersey: Pearson Prentice