Impacts of human activities of the atmosphere Flashcards
How do urban areas affect temperature? + one fact to prove it
Increase – urban heat island effect
Average temperature difference between London and rural areas is 1.3*C
Why do urban areas increase temperature? (6 reasons)
- Darker surfaces – decreased albedo
- Windows – glass reflects light towards the ground
- More pollution
- Less vegetation – evapotranspiration has a cooling effect
- Less surface water
- Less wind
How do urban areas affect precipitation? + one fact to prove it
Increase
5 – 15% more precipitation in urban areas
Why do urban areas affect precipitation? (4 reasons)
- Higher evapotranspiration
- Orographic rainfall
- Pollution for condensation nuclei
- Prevailing wind makes air move downwards away from the urban area so there is higher rainfall downwind from the city
How do urban areas affect wind? + one fact to prove it
Increase + decrease
Mean wind speeds are 20-30% lower in urban areas than rural
Why do urban areas affect wind?
Decrease = friction above and around buildings
Increase = convection from higher temperatures = stronger winds
Urban canyoning (venture effect)
How do urban areas affect cloud cover? + one fact to prove it
Increase
Up to ten per cent more frequent cloud cover
How do urban areas affect thunder storms? + one fact to prove it
Increase
Likelihood of thunderstorms is increased by 25%
Why do urban areas affect thunderstorms?
Thunderstorms develop in hot humid air
How do urban areas affect hail? + one fact to prove it
Increase
There is a 400% greater incidence of hailstorms
How do urban areas affect humidity? + one fact to prove it
Increase
Why do urban areas increase humidity?
The air is warmer in cities, therefore it can hold more moisture
How do urban areas affect acid rain? + one fact to prove it
Increase
How do urban areas affect fog? + one fact to prove it
Increase
Fogs and mists tend to be thicker and last longer in urban areas
