Urban Climates
How does human activity affect
climate?
The Effects of the Urban Climate
in the U.K.
WHY?
Urban Heat Island
London night –
May
Why best at
night?
In high pressure?
Where highest?
Where lowest?
Range?
Draw a cross-section
Urban heat Island cross-section – USA City
Albedos
Nearer to 1 =
more energy
reflected
Car engines /
exhausts
Buildings with central heating
Impact of parks?
when greatest?
Urban Rainfall
Sun’s energy absorbed by buildings
Decreased air pressure
Increased air pressure
Cumulus cloud where rising warm air meets colder air
Convectional rain
More dust particles for condensation nuclei
Urban Winds
• Wind is funnelled by tall
buildings
• Prevailing wind
• Gusty winds may be two
or three times stronger
than average
• ‘canyon’ effect of tall
buildings
Future Trends – different cities
What are the advantages and disadvantages of the urban microclimate for a city
dweller?
What trends can we see for ‘all’ cities?