urban climate Flashcards
1
Q
what is the urban heat island effect?
e.g: Melbourne’s heat island is…
A
- urban areas are warmer than surrounding rural areas
- Melbourne’s heat island - 1.13 degrees
2
Q
what is the urban heat island effect?
e.g: Melbourne’s heat island is…
A
- urban areas are warmer than surrounding rural areas
- Melbourne’s heat island - 1.13 degrees
3
Q
venturi effect
A
- when the airflow of wind is squeezed, high velocities are produced
- this effect increases as buildings tend to get taller towards city centre
4
Q
albedo?
examples?
A
the amount of heat reflected off certain surfaces
- grass albedo is 16-26%
- concrete albedo is 10-35%
5
Q
sky view factor
A
the amount of sky we can see without our view being impacted by tall buildings
6
Q
wider impact of urban heat island..
A
- UHI increases convection leading to showers and more chance of storms by up to 25%
- low pressure draws moist air in which increases cloud coverage
- urban areas receive up to 10% more coverage
7
Q
downdraught effect
A
- air is being deflected (either up or down) when it hits the building
- predominantly on windward side of the building
8
Q
speed effect
A
- air moves at a faster rate when there’s a higher altitude
- friction near the ground causes a slower rate at a lower altitude
9
Q
down wind eddy / counter current effect
A
- wind blows over building
- low pressure area on leeward side of building
- air sinks down to fill the area of low pressure
- forms a cycle of air movement currents
10
Q
where does air pollution mainly come from?
A
- vehicle / transport emissions
- industry
11
Q
particulate pollution
A
the release of particles and noxious gases into the atmosphere
12
Q
photochemical pollution
A
creates smogs consisting of ozone and peroxyacetly nitrate (PAN)
13
Q
Londons Pea Souper smog - 1953
- cause?
- why was it amplified?
- Deaths?
A
- cause: power stations and people heating homes with cheap coal
- amplified by: lack of wind
- 12,000 deaths
14
Q
what did the London smog of 1953 lead to?
A
clean air act of 1956
15
Q
why do HICs experience less pollution today?
A
- more money to invest in environment schemes
- more regulations in HICS
- HIC populations use cleaner energy sources
- LICs often based on manufacturing
16
Q
long term impacts of air pollution
A
- shorter life expectancy
- increased health issues so people can’t work so less income which slows economic growth
- loss of tourism
17
Q
urban areas have ____% more precipitation than rural areas
A
5-15% more precipitation
18
Q
why is there more urban precipitation?
A
- dust and pollution create more condensation nuclei
19
Q
why is there a higher risk of flooding in urban areas?
A
- less vegetation so less evapotranspiration
- impermeable surfaces
- gutters and drains quickly carry water to rivers meaning lag time is shorter
20
Q
ways of reducing air pollution
A
- urban green areas
- zoning of industry
- transport solutions
- clean air acts
21
Q
how does urban greening help?
A
- vegetation absorbs CO2 and releases oxygen
- removes pollutants from air
- makes air cleaner/healthier
22
Q
an example of urban greening
A
London
- mayor wants to increase amount of surface areas greened by 5% by 2030
23
Q
how does zoning of industry help?
A
- placing industry on the outskirts of the city reduces the concentration of pollution
- less people driving into city to work in the factories
- air quality in city improves
24
Q
examples of transport solutions
A
- congestion charges in the CBD
- public transport (eg: Curitiba bus system has taken 80% of population out of cars)
- carpool lane
- promoting greener transport such as bikes
25
clean air acts
- regulate industry and how much is being emitted
| - regulates cars on how clean/efficient they are
26
what are SUDS?
- sustainable urban drainage systems
| - water management strategies designed to drain surface water moire sustainably than traditional practices
27
types of SUDS
- swales
- wetland
- permeable pavements
- infiltration trenches
- green roofs
28
swales
- provide temporary storage for storm water to reduce peak flows
- encourage microbial decomposition
29
wetland
- increased biodiversity
| - aesthetically pleasing
30
permeable pavemets
- reduces flooding
| - pollutant removal takes place in sub-base material
31
infiltration trenches
- stone filled reservoirs which water gradually infiltrates
| - pollutants removed by absorption and microbial decomposition
32
what three objectives are SUDS aimed towards?
- control quantity of run-off
- improve quality of run-off
- enhance nature conservation
33
venturi effect
- when the airflow of wind is squeezed, high velocities are produced
- this effect increases as buildings tend to get taller towards city centre
34
albedo?
| examples?
the amount of heat reflected off certain surfaces
- grass albedo is 16-26%
- concrete albedo is 10-35%
35
sky view factor
the amount of sky we can see without our view being impacted by tall buildings
36
wider impact of urban heat island..
- UHI increases convection leading to showers and more chance of storms by up to 25%
- low pressure draws moist air in which increases cloud coverage
- urban areas receive up to 10% more coverage
37
downdraught effect
- air is being deflected (either up or down) when it hits the building
- predominantly on windward side of the building
38
speed effect
- air moves at a faster rate when there's a higher altitude
| - friction near the ground causes a slower rate at a lower altitude
39
down wind eddy / counter current effect
- wind blows over building
- low pressure area on leeward side of building
- air sinks down to fill the area of low pressure
- forms a cycle of air movement currents
40
where does air pollution mainly come from?
- vehicle / transport emissions
| - industry
41
particulate pollution
the release of particles and noxious gases into the atmosphere
42
photochemical pollution
creates smogs consisting of ozone and peroxyacetly nitrate (PAN)
43
Londons Pea Souper smog - 1953
- cause?
- why was it amplified?
- Deaths?
- cause: power stations and people heating homes with cheap coal
- amplified by: lack of wind
- 12,000 deaths
44
what did the London smog of 1953 lead to?
clean air act of 1956
45
why do HICs experience less pollution today?
- more money to invest in environment schemes
- more regulations in HICS
- HIC populations use cleaner energy sources
- LICs often based on manufacturing
46
long term impacts of air pollution
- shorter life expectancy
- increased health issues so people can't work so less income which slows economic growth
- loss of tourism
47
urban areas have ____% more precipitation than rural areas
5-15% more precipitation
48
why is there more urban precipitation?
- dust and pollution create more condensation nuclei
49
why is there a higher risk of flooding in urban areas?
- less vegetation so less evapotranspiration
- impermeable surfaces
- gutters and drains quickly carry water to rivers meaning lag time is shorter
50
ways of reducing air pollution
- urban green areas
- zoning of industry
- transport solutions
- clean air acts
51
how does urban greening help?
- vegetation absorbs CO2 and releases oxygen
- removes pollutants from air
- makes air cleaner/healthier
52
an example of urban greening
London
| - mayor wants to increase amount of surface areas greened by 5% by 2030
53
how does zoning of industry help?
- placing industry on the outskirts of the city reduces the concentration of pollution
- less people driving into city to work in the factories
- air quality in city improves
54
examples of transport solutions
- congestion charges in the CBD
- public transport (eg: Curitiba bus system has taken 80% of population out of cars)
- carpool lane
- promoting greener transport such as bikes
55
clean air acts
- regulate industry and how much is being emitted
| - regulates cars on how clean/efficient they are
56
what are SUDS?
- sustainable urban drainage systems
| - water management strategies designed to drain surface water moire sustainably than traditional practices
57
types of SUDS
- swales
- wetland
- permeable pavements
- infiltration trenches
- green roofs
58
swales
- provide temporary storage for storm water to reduce peak flows
- encourage microbial decomposition
59
wetland
- increased biodiversity
| - aesthetically pleasing
60
permeable pavemets
- reduces flooding
| - pollutant removal takes place in sub-base material
61
infiltration trenches
- stone filled reservoirs which water gradually infiltrates
| - pollutants removed by absorption and microbial decomposition
62
what three objectives are SUDS aimed towards?
- control quantity of run-off
- improve quality of run-off
- enhance nature conservation
