CUE - Urban Climate: Key Terms Flashcards
Albedo
The reflectivity of a surface.
It is the ratio between the amount of incoming insulation and the amount of energy reflected back into the atmosphere.
Light surfaces reflect more than dark surfaces so have a greater albedo.
Isotherm
A line joining places with equal temperature
Channelling
Wind redirected down long, straight canyon-like streets where there is less friction. These are sometimes referred to as urban canyons.
Venturi effect
The squeezing of wind into an increasingly narrow gap, resulting in a pressure decrease and velocity increase of winds.
Microclimate
The small-scale variations in temperature, precipitation, humidity, wind speed and evaporation that occur in a particular environment such as an urban area.
Urban dome
The urban microclimate is sometimes called an urban dome. This is the area within which the weather is different from that of surrounding rural areas. There are 2 levels in the dome: the Urban Canopy and the Urban Boundary Layer.
Photochemical pollution/smog
A form of air pollution that occurs mainly in cities and can be dangerous to health. Exhaust fumes become trapped by temperature inversions and, in the presence of sunlight, low-level ozone forms. It is associated with high-pressure weather systems.
Temperature inversion
Atmospheric condition in which temperature, unusually increases with height. As in versions are extremely stable conditions and do not allow convection, they trap pollution in the lower layer of the atmosphere.
Urban heat island
The zone around and above an urban area, which has higher temperatures than the surrounding rural areas.
Carbon monoxide
A colourless, tasteless, odourless, poisonous gas produced by incomplete combustion of fuel.
Nitrogen dioxide
Reacts with hydrocarbons in sunlight to create ozone and contributes to the formation of particles.
Particulate matter (PM)
Tiny bits of solids or liquids in the air.
Sulphur dioxide
A colourless gas with a strong odour when a material or fuel containing sulphur is burned.
Smog
A mixture of fog and smoke particulates.
