To what extent do urban areas modify their climate?
Amelia Scotney
‘To what extent do urban areas modify their climate?’ – 40 marks.
Cities create their own microclimates and their sites are almost always warmer, compared to a nearby rural location, than if the city were not there. The differences in urban climates are due to a number of different factors.
The Urban Heat Island effect is known as the zone of hot air that develops over the urban areas and consequently higher temperatures than the surrounding rural area. Temperatures progressively decline as you move further from the urban areas; an example of this can be seen between Central London and the surrounding area, as there is a temperature difference of 6 degrees. However, even small urban areas can have urban heat island effects.
Heat islands form for a variety of reasons that aren’t present in the surrounding rural areas. For example, urban areas have extensive dark surfaces (roads and roofs) and absorb heat during the day and release it slowly at night when the temperatures cool. Urban heat island effect is particularly visible at night time due to this reason, as the urban areas still retain heat even when the rural areas are much cooler. Temperature differences between urban and rural areas can vary from 0.6 degrees (day) to 3-4 degrees (night). People and human activities such as transport, industry and power stations also generate their own heat. The pollutants from cars act as a condensation nuclei leading to the formation of cloud and smog, which traps radiation within the area. On average urban areas contain 10 times the amount of condensation nuclei than rural areas. The lack of vegetation in urban areas reduces the amount of moisture in the air. This is intensified by drains and sewers, which remove surface water quickly.
On average, precipitation rates are 5-10% higher in urban areas than in rural areas. The main reason for this trend is that urban areas tend to make more condensation nuclei; the tiny particles are
‘To what extent do urban areas modify their climate?’ – 40 marks.
Cities create their own microclimates and their sites are almost always warmer, compared to a nearby rural location, than if the city were not there. The differences in urban climates are due to a number of different factors.
The Urban Heat Island effect is known as the zone of hot air that develops over the urban areas and consequently higher temperatures than the surrounding rural area. Temperatures progressively decline as you move further from the urban areas; an example of this can be seen between Central London and the surrounding area, as there is a temperature difference of 6 degrees. However, even small urban areas can have urban heat island effects.
Heat islands form for a variety of reasons that aren’t present in the surrounding rural areas. For example, urban areas have extensive dark surfaces (roads and roofs) and absorb heat during the day and release it slowly at night when the temperatures cool. Urban heat island effect is particularly visible at night time due to this reason, as the urban areas still retain heat even when the rural areas are much cooler. Temperature differences between urban and rural areas can vary from 0.6 degrees (day) to 3-4 degrees (night). People and human activities such as transport, industry and power stations also generate their own heat. The pollutants from cars act as a condensation nuclei leading to the formation of cloud and smog, which traps radiation within the area. On average urban areas contain 10 times the amount of condensation nuclei than rural areas. The lack of vegetation in urban areas reduces the amount of moisture in the air. This is intensified by drains and sewers, which remove surface water quickly.
On average, precipitation rates are 5-10% higher in urban areas than in rural areas. The main reason for this trend is that urban areas tend to make more condensation nuclei; the tiny particles are