METEOROLOGIST JEFF HABY
An urban heat island is the warmer temperatures that can be experienced over an urban area. There are several factors that can make the
temperature warmer over an urban area. One factor is the heat absorbed by buildings and concrete. Less energy is available for use by
photosynthesis (less vegetation in the city) and for latent heat absorption (less water such as soil moisture and plant moisture
in the city), thus more solar radiation goes into direct warming in an urban area. Another factor is the presence of greenhouse gases. The
carbon dioxide released by cars and factories increases the amount of longwave energy absorbed in the air which in turn increases the
air temperature. Another factor is light wind. When the wind is light, there is less mixing between the air over the city and the air
in the rural areas. When winds are light there will tend to be a greater temperature difference between the country and the city. This
can produce an urban heat island.
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