Urban Climate Flashcards
(30 cards)
Explain the term ‘Albedo’
How much a surface can reflect heat
In UHI’s what is a ‘Sink’
Areas of cool air above parks and bodies of water
Which weather system leads to clear skies and low winds, in turn leading to a greater UHI effect?
Anticyclones
How does air pollution affect UHIs?
It causes increased cloud cover which traps heat and reflects it back to the surface.
What type of map can be used to examine temperatures in UHIs?
Isotherm maps
Why is fog more frequent in urban areas?
Higher concentration of condensation nuclei
What three items are required to form a thunderstorm?
Humidity, rapid uplift and instability
Why are frost+ snow less likely in urban
areas?
UHI effect
Why is average wind speed lower in urban areas?
Tall buildings create friction which slows down moving air.
What name is given to the rapid and abrupt changes in direction of wind in urban areas?
Turbulence
What effect is caused by wind being channelled down streets?
Canyon effect
What are vortices caused by?
Turbulent wind hitting other buildings or the ground.
What causes ‘Eddying’
Pressure gradients between windward and leeward sides of buildings
Why is Chicago known as ‘The Windy City’?
Grid system of buildings causes wind tunnels.
What are the main causes of: Particles or particulate matter- Carbon monoxide
Nitrogen dioxide
Sulphur Dioxide
Vehicle exhausts, Road transport ,Coal and oil burning
Smog is a mixture of what two airborne items?
Smoke and Fog
What nickname was given to the occurrence of thick smog?
‘Pea-souper
What causes photochemical smog?
Pollutants (eg nitrogen and sulphur oxides) coming into contact with sunlight, and breaking down into harmful chemicals such as Ozone.
Explain what is meant by
Temperature Inversion
A layer of warm air forms on top of a layer of cold air.
Why did Los Angeles have such
problems with photochemical smog?
Millions of vehicles, frequent sunshine and basin topography.
Why are anticyclonic conditions a
particular problem with air pollution?
Air descends and is static due to lack of wind.
Congestion charging
People are charged if they use their vehicle in certain places at certain times.
Reduce pollution by reducing road traffic.
E.g. London, Durham City
Pedestrianisation
Vehicles are prevented from entering certain places at certain times. Reduces pollution by reducing rad traffic. E.g. Briggate in Leeds.
Public transport improvements
Encouraging people to use public transport instead of their cars reduces pollution.
Improved bus services to make bus journeys cheaper, faster and more efficient. One way to do this is with bus lanes so buses don’t get stuck in slow traffic.
Park and ride schemes to make it easier to access public transport.
Trams and light railway services which run on lies, so they don’t get caught in road congestion. They also pollute less than buses.
