Urban climate Flashcards
Albedo
The reflexivity of a surface and it is the ratio between the amount of incoming insulation and the amount of energy reflected back into the atmosphere
Particulate air pollution
A form of air pollution caused by release of particles and noxious gases into the atmosphere
Photochemical pollution
Temperature in version
An atmospheric condition in which temperature usually increases with height, as this doesn’t allow convection they trap pollutant in the lower layer of the atmosphere
Urban heat Island
The zone around and above a urban area which has higher temperatures than the surrounding rural areas
Urban microclimate
A small scale variation and temperature, precipitation, humidity, windspeed and evaporation that occur in particular environment such as an urban area
UHI
1– 3° warmer than its surrounding areas, can be as much as 12° warmer, temperatures will fluctuate depending on season, weather conditions, sun intensity, and ground cover
Why cities tend to be warmer than
Surfaces tend to be less reflective, air pollution from industries and vehicles increases cloud cover = pollutant dome, urban areas are designed to dispose of surface water quickly reduces the potential for cooling fire evaporation reduces vegetation meaning less evaporate transpiration, heat from industries, buildings and vehicles also burn fuel
Why is it concern?
Extreme heat measures can cause health problems – heat wave of 2019 in Paris 42.6°C 1435 deaths, strain on supply of energy cooling and air-conditioning, increase water consumption, anticyclone weather conditions, higher pollution levels
Managing Urban Island effect
Cool surfaces, green roads – roads with a more poor surface allowing water to seep through, green roofs – reduce rooftop temperatures reduce rainwater run-off, urban greening
Precipitation
Rainfall can be higher over and urban areas in rural areas, this is because higher urban temperatures and increase the development of low pressure over cities in relation to surrounding areas, convectional rainfall tends to be heavier and more frequent
Fog
Thunderstorms
Develop in mid air and are characterised by violent and heavy precipitation, chance of these have increased
Channeling
Wind Direction down long straight Canon like streets where there is less fraction these are sometimes referred to as urban cannons
Venturi effect
The phenomenon in which wind velocities increase when air flows through an increasingly in our gap
Air quality
particular air pollution, particles and nauseous gases, carbon monoxide – affects transport of oxygen around the blood, nitrogen oxide – inflame lining of lawn, particulate matter – settle in airways causing health problems, sulphur dioxide – coughing tightening of chest and airways can also produce acid rain
Clean air act 1956
London smog – 1952, smoke free zones, monitor pollution, cleanup construction sites 12% of nitrogen oxide emissions, 280,000 trees planted, ultra low emission zone 2019, hybrid and zero emission and gym buses increase, 1500 electric vehicles charging points installed, £48 million scrappage fund for polluting cars
