urban climate in London

Question 1

temperature

Answer 1

west end - 31 degrees (urbanised area, buildings, glass reflecting light)
richmond park - 23 degrees (2500 acres of protected green space)
urban heat island effect - due to darker surfaces in cities (e.g., buildings and tarmac) absorbing, retaining, and releasing heat from sun slowly back into atmosphere
walkie talkie - reflect light in concentrated beam onto the street below (temp reportedly reached 70 degrees) - melting car incident 2013 (Jaguar)
protective blinds added
more built-up areas have hotter temps as more heat can be absorbed

Question 2

Precipitation

Answer 2

in average year 200 dry days out o f365
total of around 23 inches across year
much rainier within london - because of UHI meaning more evaporation and precipitation

Question 3

fogs and thunderstorms

Answer 3

great fog of London (1952) - killed 4000
covered city for 5 days - caused by combination of industrial pollution and higher pressure weather conditions keeping pollution in atmosphere
thunderstorms most common in London and southeast
London seeing electrical storrms 30 days annually

Question 4

Wind

Answer 4

walkie talkie - 34 stories costing over £200 million
wind much more intense at base due to
downdraught effect - wind hitting a building and being forced downward and around (acceleration of wind if building squared corners)
Venturi effect - channelling of wind between buildings, squeezing the wind through a tunne;
rounder buildings (e.g., London’s gherkin) doesnt have same downdraught effect - winds arent as intense
cities reduce level of wind conditions deemed tolerable - prevents further buildings to prevent creating microclimates (tougher guidelines)

Question 5

Air quality

Answer 5

within city of Westminster (victoria street) air quality consistently poor - index of air quality by London air
PM10 - 10 (very high) PM2 - 6 (moderate)
worsens in winter and low winds as pollution and emissions are trapped near ground due to cold temperature inversion
people asked to reduce physical exertion especially when experiencing coughing and sore throat
air polluted inner city
richmond park - PM10 - 2 (low) PM2 - 2 (Low)
2020 - urban populations in south east at greater risk from air pollution
2015 - over 9000 Londoners dying early every year due to toxic air
approximately 50% pollution from road transport

Question 6

pollution reduction policies

Answer 6

ULEZ - central london - most vehicles driving in zone must meet tight emission standards or pay daily charge
when zone expands 18x larger
2021 - 44,000 fewer dirty vehicles driving into London
air pollution plunged sinze new mayor in 2016 (94% reduction in people living in areas with high levels of pollution)
protected space for cyclists
city trees (2020) - towers filled with moss that eats pollution whilst producing oxygen (takes in as much pollution as 275 regular trees)