10. Urban microclimate (25 minutes) - Pearson

Answers:
LEVEL: AS
GEOGRAPHY
10. Urban microclimate (25 minutes)
Study the map below showing the distribution of minimum temperature over London during a
night in May.
(a)
(i) What is the name give to lines linking places of equal temperatures?
(1 mark)
Isotherms (REMEMBER THERMS – THERMOMETERS).
(ii) What name is given to the situation shown in the map?
(1 mark)
The urban heat island effect.
(iii) What atmospheric conditions allow this pattern of temperatures to develop?
(3 marks)
Calm conditions, no wind (allows heat to build up).
Hot, cloudless day (allows maximum insolation).
Cloudless night skies (allow heat to escape).
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Answers:
LEVEL: AS
GEOGRAPHY
(iv) In what ways does the built-up area contribute to the development of this temperature
pattern?
(5 marks)
Heat absorbed by buildings and tarmac in the day is released at night.
Many dark colours to absorb solar insolation.
Domestic heating adds to natural heat release.
(v) What effects do rivers and reservoirs have on the pattern of temperatures? Give an example
to help your explanation.
(2 marks)
REMEMBER WATER COOLS TEMPERATURES
They displace the isotherms, especially along the Thames Valley in East London.
(b)
(i) In what ways does the microclimate around London differ from the microclimate of the
surrounding countryside?
(3 marks)
London’s microclimate has more cloud and rain, lower humidity and windspeed and higher
temperatures.
(ii) Give reasons for these differences.
(6 marks)
More cloud creates more condensation nuclei which create more rain. The lower humidity is the result
of less transpiration and evaporation. Buildings block wind, leading to lower windspeeds.
Temperatures are higher since less radiation is absorbed as much is reflected (from glass) and absorbed
by concrete during the day.
(c) For a city or cities you have studied, describe how pollution from them, have caused health
problems to the related populations.
(9 marks)
City case studies often focus on Mexico City and Los Angeles. The main pollutants are cars and
industry. Name these pollutants and describe their effect on people directly and indirectly (visibility).
(Total marks 30)
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