THE CONCEPT OF URBAN HEAT ISLAND

URBAN HEAT ISLAND

Refers to the situation where by  urban areas are warmer compared to sub-urban or rural areas, this occur due to temperature difference  between urban and sub urban or rural areas.

The temperature difference of these areas are caused by the following factors.

CAUSES OF URBAN HEAT ISLAND

i)                    Dark surface / objects

ii)                   Lack of evapotranspiration in urban areas (for example through lack off vegetation)

iii)                 Existence of tall buildings

EFFECTS OF URBAN HEAT ISLAND

i)                    Increase day time temperature, reduced night time cooling

ii)                   Increase the use of air conditions

iii)                 It cause general discomfort, for stance respiratory difficulties, even death related mortality.

MITIGATION OF URBAN HEAT ISLAND

i)                    White roofs

Ø  Painting roofs tops white to increase reflection and reduce absorption of incoming solar radiation

ii)                   Green roofs

Ø  This is the practice of having vegetation on a roof such as having trees or a garden purposely to increase evapotranspiration

iii)                 Planting trees in cities

Ø  Also for the purpose of increasing evapotranspiration

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