Large Cities Have Their Own Climatic Conditions
Large cities have their own climatic conditions. To what extent is this true? (40 marks)
Large cities have their own climatic conditions and can be referred to as having a micro-climate. Micro-climates are small scale variations in temperature, precipitation, humidity, wind speed and evaporation that occur in an environment. This would therefore suggest that the statement is in fact true.
Large cities create their own climate and weather which is known as the ‘urban climate dome’ within which weather is different from the surrounding rural areas. This dome is split in two levels, the first being below roof level where there is an urban canopy where processes act in the space between buildings (also known as canyons). This is caused due to spatially integrated heat and moisture exchanges between the city and its overlying air. The second layer is the urban boundary layer where the dome extends downwind and at height as a plume into the surrounding rural areas. Fluxes across this plane comprise those from individual units, such as roofs, canopy tops, trees and roads, integrated over larger land-use divisions such as suburbs.
The first factor would suggest that the statement is true is that there is a difference in temperature in large cities due to the urban heat island as on average in cities, temperatures are one to three degrees warmer but on occasions can be as much as ten degrees higher than the surrounding rural area. There are a variety of reasons why the urban heat island occurs. One of these is the building materials used to construct cities like bricks and concrete. These materials have high heat capacities and ability to conduct heat. Therefore, they are able to absorb and store large amounts of heat in the day which is slowly released at night. Another reason is that the vertical walls and roofs of buildings increase the area exposed at the surface, further enhancing the absorption and storage of heat. In addition to this, they also reduce the ability
Large cities have their own climatic conditions and can be referred to as having a micro-climate. Micro-climates are small scale variations in temperature, precipitation, humidity, wind speed and evaporation that occur in an environment. This would therefore suggest that the statement is in fact true.
Large cities create their own climate and weather which is known as the ‘urban climate dome’ within which weather is different from the surrounding rural areas. This dome is split in two levels, the first being below roof level where there is an urban canopy where processes act in the space between buildings (also known as canyons). This is caused due to spatially integrated heat and moisture exchanges between the city and its overlying air. The second layer is the urban boundary layer where the dome extends downwind and at height as a plume into the surrounding rural areas. Fluxes across this plane comprise those from individual units, such as roofs, canopy tops, trees and roads, integrated over larger land-use divisions such as suburbs.
The first factor would suggest that the statement is true is that there is a difference in temperature in large cities due to the urban heat island as on average in cities, temperatures are one to three degrees warmer but on occasions can be as much as ten degrees higher than the surrounding rural area. There are a variety of reasons why the urban heat island occurs. One of these is the building materials used to construct cities like bricks and concrete. These materials have high heat capacities and ability to conduct heat. Therefore, they are able to absorb and store large amounts of heat in the day which is slowly released at night. Another reason is that the vertical walls and roofs of buildings increase the area exposed at the surface, further enhancing the absorption and storage of heat. In addition to this, they also reduce the ability