Urban Climates

Question 1

What are the general impacts of Urban Climates?

Answer 1

• higher T°C:
  
  • greater SA to absorb heat
  • low albedo of tarmac + concrete so less insolation reflected
  • high buildings trap insolation + absorb heat
  • more heat for atmo. due to dec. evtp
  • pollutants trap heat
• lower humidity:
  
  • lack of veg. so less transpiration
  • high drainage density removes water
  • fewer bodies of water so less water available or evaporate
• more intense storms:
  
  • greater instability of air, so stronger convection above urban areas
• slower winds:
  
  • wind scattered by buildings
• less snowfall:
  
  • due to higher T°Cs

Question 2

What are the general causes of Urban Climates?

Answer 2

• human activity: radiant heat from heating systems + buildings contributed up to 50%
• insolation: due to pollution, longwave radiation is trapped + insolation dec.