3.2.3.4 Urban Climate

Question 1

Define the urban heat island effect

Answer 1

• the temperature in urban microclimates being higher than surroundings
• can be upwards of 5 degrees in summer

Question 2

3 reasons for the urban heat island effect

Answer 2

• surfaces in urban areas have a lower albedo
• pollutants trapping radiation (condensation nuclei)
• absense of water for evapotranspiration

Question 3

Managing urban heat island effect

Answer 3

• green roofs
• cool pavements
• increase in vegetation

Question 4

Masdar (Abu Dhabi)

Answer 4

• 40k people
• Solar energy
• natural shade
• utilises Venturi effect for cooling

Question 5

Fogs

Answer 5

• urban areas increases fog
• Kew, middle of London, 79 hours of fog yearly
• Heathrow, outskirts of London, 40 hours of fog
• 1952 London ‘pea soup’ fog caused 4000 deaths

Question 6

Rainfall

Answer 6

• increased rainfall in urban areas
• pollution induced (condensation nuclei)
• rapid evapotransipration rates

Question 7

Thunderstorms

Answer 7

• the likelihood of a thunderstorm is increased by 25% in urban areas

Question 8

Wind

Answer 8

• generally, wind is decreased because buildings create drag
• venturi effect: narrow gaps increasing velocity
• channeling: gaps in buildings dragging down wind

Question 9

Types of pollutants

Answer 9

• particulate matter
• CO and CO2
• NO2

Question 10

How many deaths a year are attributed to pollution in the UK

Answer 10

40,000