1. URBAN MICROCLIMATES

2. Construction of cities lead to: Profound changes in the climate of a specific locality

3. What do cities do?
They destroy the existing microclimate and create new ones.
There are three processes involved:
1. production of heat
2. alteration of land surface
3. modification of the atmosphere

4. PRODUCTION OF HEAT Combustion of fuels
Release of heat stored in city’s brickwork and concrete
Creation of ‘urban heat island’

5. Altlanta urban heat island

6. Urban heat profile

7. Another urban heat profile!

8. Urban temperature transect

9. ALTERATION OF LAND SURFACE
Buildings and streets can change wind speeds

10. Other urban variables to consider:

11. Wind velocities can vary very locally in urban areas

12. Wind velocities can be increased!

13. MODIFICATION OF THE ATMOSPHERE
Air pollution reduces sunlight
Development of smog
Calm conditions with descending air and warm pollutants rising create an inversion layer.

14. Los Angeles inversion layer

15. Increase in condensation nuclei leading to fog