Climate on a local scale: urban climates Flashcards
What does albedo mean?
Albedo si the reflectivity of a surface and the ratio between the amount of incoming insolation and the amount of energy reflected back into the atmosphere.
What is a microclimate?
It is a small scale variation in temperature, precipitation, humidity, wind speed and evaporation in the environment.
What is photochemical smog?
A type of air pollution that appears mainly in urban areas that can be dangerous to health.
What is a temperature inversion?
An atmospheric condition where temperature increases with altitude. They are very stable conditions that don’t allow convection and therefore trap pollution in the lower layer of the atmosphere.
What is an urban heat island?
The zone around and above and urban area which has higher temperatures that the surrounding rural areas.
How are urban heat islands formed?
The urban surfaces like concrete and tarmac absorb the suns insolation during the day and store it and release it over night, keeping the urban areas warmer that normal than the surrounding rural areas.
Also as water flows straight to drains there is less evaporation leading to more heat stored in the urban surfaces.
What effect does a heat island have on precipitation?
There is some evidence that there may be more precipitation over urban areas due to the warmer areas producing low pressure and rising air that cools and condenses to form clouds –> rain
