Urban Climate Flashcards
What is the urban heat island?
The phenomenon of urban areas being warmer than rural areas
What is an example of a place that has a clearly defined UHI?
London
Where are the highest temperatures in cities with a UHI?
Industrial areas - CBD
What are temperature ‘sinks’?
Pockets of cool air above parks and bodies of water
What are temperatures ‘plateaus’?
Areas within the city with the same land use generally have the same temperatures.
What are rapid changes of temperature called?
Temperature ‘cliffs’
What are 4 main causes of UHI effect?
Absorption of heat by urban surfaces
Air pollution
Heat from human activity
Less evapotranspiration
How does absorption of heat by urban surfaces cause a UHI?
Concrete, brick and tarmac surfaces absorb and store heat from the sun during the day.
How does air pollution cause a UHI?
Air pollution increases cloud cover over the city. It also creates a pollution dome.
What’s a pollution dome?
A layer of pollution over the city.
How does heat from human activity cause a UHI?
Everything releases heat
How does less evapotranspiration cause a UHI?
When it rains the water’s quickly removed by drainage systems so there’s less water to evaporate.
When is the UHI effect stronger?
At night
Why is the UHI effect stronger at night?
Because rural areas cool down bur urban don’t - surfaces still release heat.
Why is average wind speed usually lower in cities than rural areas?
Tall buildings create friction that slows down the moving air.
