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A Level Human Geography > CUE - Urban Climate > Flashcards

Flashcards in CUE - Urban Climate Deck (30)
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1
Q

What is the urban climatic dome?

A

The urban area within which the climate and weather is different from that of the surrounding rural areas in terms of temperature, relative humidity, precipitation, visibility, air quality and wind speed.

2
Q

Urban weather has less…

A
sunshine duration
occurrence of frosts
relative humidity in winter
relative humidity in summer
snowy days
3
Q

Urban weather has more

A
total precipitation
rainy days
annual mean temp
winter max temp
cloud cover
occurrence of fog
condensation nuclei
4
Q

What is the urban canopy?

A

The urban canopy is the layer of air closest to the surface in the cities, extending upwards to mean building height, where processes act in the spaces between buildings.

5
Q

What is the urban boundary layer?

A

The layer above the urban canopy, that forms a dome of warmer air that extends downwind and, at height, as a plume into surrounding rural areas.

6
Q

How do urban surfaces have different albedos than rural areas?

A

In urban areas there are more dark surfaces such as pavements and roofs, which have a very low albedo. In addition, there are many highly reflective buildings made from glass which have very high albedos but reflect the heat back onto the ground and into the city.

7
Q

4 reasons why temperatures fluctuate in urban areas

A

season
weather conditions
sun intensity
ground cover

8
Q

4 causes of the urban heat island

A

albedo - building materials have low albedo so absorb heat in day and release at night, large windows concentrate heating effect into surrounding streets by reflecting energy downwards
air pollution - industries and vehicles, increases cloud cover and creates pollution dome
urban moisture and heat budget - water falling on surface disposed of asap, reducing evapotranspiration, more energy can heat atmosphere
industry and people - industries, buildings vehicles burn fuel. air conditioning units release hot air to atmosphere. people generate heat

9
Q

Issue with the urban heat island: as temperatures rise in the summer months…

A

Conditions in buildings and on city transport systems can become uncomfortable. Increases cases of heat stroke, asthma, organ damage and death. Babies and elderly are most likely to be affected.

10
Q

Issue with the urban heat island: Hot and still anticyclonic weather conditions responsible for intensive urban heat island events…

A

Also produce higher air pollution levels.

11
Q

Issue with the urban heat island: prolonged survival and high reproduction rates of…

A

Some animal and insect pests can be a problem. There is greater potential of algal blooms in water courses.

12
Q

Issue with the urban heat island: earlier flowering times of…

A

plants and trees in cities and a prolonged growing season may cause discomfort for city residents due to a longer allergy season.

13
Q

Issue with the urban heat island: increased water consumption…

A

by residents and businesses places extra strain on the water supply infrastructure and can lead to water use restrictions.

14
Q

Issue with the urban heat island: excessive heat puts…

A

an increased strain on the supply of energy for cooling and air conditioning.

15
Q

Issue with the urban heat island: climate change…

A

is expected to increase the intensity of the urban heat island effect in most urban areas.

16
Q

Issue with the urban heat island: an increased risk of the deterioration…

A

of historical monuments and buildings through increased rates of temperature related chemical weathering.

17
Q

Strategies to address the issues with the urban heat island: cool surfaces

A

roofs built from materials with high albedo absorb and store less solar energy during the day, so emit less heat at night.

18
Q

Strategies to address the issues with the urban heat island: green roofs

A

reduce rooftop temperatures by up to 20-40 degrees. reduce rainwater runoff, act as insulators and increase urban biodiversity.

19
Q

Strategies to address the issues with the urban heat island: urban greening

A

planting trees and vegetation provides shade and can have a natural cooling effect. they also act as carbon stores, can reduce urban flooding and filter pollutants from the air.

20
Q

Strategies to address the issues with the urban heat island: sky view factor

A

the openness between buildings in an urban area. a restricted sky view reduces the escape of heat from street and building surfaces, contributing to heat within street canyons.

21
Q

Strategies to address the issues with the urban heat island: cool cars

A

a lighter coloured car reflects more sunlight than a traditional dark car. this cools the inside of the car and reduced the need for air conditioning.

22
Q

Causes of photochemical smog

A

2 main causes are vehicles and industry

  • most likely in anticyclonic conditions: high pressure system, dry, little wind or cloud
  • also when temperature inversions occur (cold air trapped under warm): e.g in LA (where there’s a basin)
  • pollutants are trapped
  • sunlight reacts with pollutants (e.g nitrogen oxides)
23
Q

Where does carbon monoxide mainly come from?

A

road transport

24
Q

What causes nitrogen dioxide?

A

road transport (50%)

25
Q

Where do particulates mainly come from?

A

Power stations and vehicle exhausts

26
Q

Source of sulphur dioxide

A

industry e.g power stations

27
Q

Impact of carbon monoxide

A

affects the transport of oxygen around the body

breathing in low levels can result in: headaches, fatigue, nausea

28
Q

Impact of nitrogen dioxide

A

can inflame the lining of the lung - worse for people who suffer from asthma
oxidation of this can also cause weathering of buildings

29
Q

Impact of particulates

A

health problems for the airway and lungs

30
Q

Impact of sulphur dioxide

A

coughing tightening of chest and narrowing of airways

can also produce haze, acid rain, damage to plants and buildings

Decks in A Level Human Geography Class (41):