3.2.3.4 - Urban Climate Flashcards
What aspect of the climate can urban areas modify?
Windspeeds
Temperature
Clouds of precipitation.
Pollution.
In what ways can winds be modified by urban areas?
Lower speeds
Greater variability.
Large-scale convection.
Why are windspeeds generally lower in urban areas?
The roughness of the land surface, consisting of buildings, at a variety of heights, create greater surface friction
What is an urban canyon?
A street with tall buildings, either side, but a space in between
What is the Venturi effect?
The effective squeezing the airflow, increased as buildings, get taller towards the city centre
Where is the highest air pressure?
In the upper part of the building with air flowing down the front and over the top
How does convection occur over urban areas?
Convection and uplift over the area means that air pressure is lowered and air is drawn in from surrounding rural areas
What is the urban heat island?
Urban areas are an average 2° warmer than the surrounding rural areas
What is albedo?
the ability of a surface to reflect sunlight. Light-colored surfaces (high albedo) reflect more sunlight than dark-colored surfaces (low albedo).
What is Skyview factor?
The amount of sky you can see without your view being impeded by Toe buildings
What is specific heat capacity?
The amount of energy required to raise the temperature of 1 kg of the material by 1 kelvin
What is the intensity of an urban heat island?
The maximum difference between the temperature of the ruralarea and the peak urban temperature
How can weather conditions impact the intensity of the urban heat island?
High pressure systems with clear nights and sunny days increase the intensity
What are the five main factors causing having heat island?
Anthropogenic heat
Height in arrangement of buildings.
Nature of building materials.
Presence of water.
Pollutants.
What is sensible heat?
Heat energy, which can be felt, as opposed to latent heat, which must be measured
