3234 - Urban Climate Flashcards
Define urban climate
The small scale variations in temperature, precipitation, humidity, wind speed and evaporation than occur in a particular environment e.g an urban area
Define urban dome
The urban microclimate is sometimes called an urban dome. This is the area within which the weather is different from that of the surrounding rural areas. The two levels in the dome is the urban canopy and the urban boundary
Define 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 and so have a greater albedo
What kind of surface has a low albedo
A dark surface that absorbs light
What kind of surface has a high albedo
A lighter colour that reflects light
How is albedo expressed
On a scale from 0-1
0= total absorption
1= complete reflecting/ance of solar radiation
What is the albedo of grass
0.25-0.30
Albedo of tar/ gravel
0.03-0.18
Albedo of highly reflective roof
0.60-0.70
What does a high albedo mean
The surface reflects the majority of the radiation that hits it and absorbs the rest
What does a low albedo mean
A low albedo means a surface reflects a small amount if the incoming radiation and absorbs the rest
