Atmosphere and Weather Flashcards
What is meant by the term Albedo?
The proportion of energy reflected back to the atmosphere depending on a surface’s reflectivity
Define reflected solar radiation
The energy from the sun as short wave radiation that is not absorbed by the surfaces
Define sensible heat transfer
Heat exchanged by conduction / convection between warmer and colder bodies or a change in temperature of an object by heat exchange with no phase change
Briefly explain how dew is formed (3)
By condensation of moisture on a surface as the air is cooled to dew point or by contact with a surface losing heat by radiation
Explain why night time temperatures vary across an urban area (5)
- Release of heat absorbed during the day
- Variations in amount of heat absorbed due to surface characteristics e.g. albedo / density
- Heat released from anthropogenic sources e.g. heating and lighting of buildings / power stations / industry / vehicles
- Pollution blanket
- Protection against wind
- Variations in density of buildings (open space)
Briefly describe how some incoming solar radiation is prevented from reaching the earth’s surface (3)
- Absorption from the atmosphere
- Reflection by clouds
- Scattering by dust
Define short wave radiation
Incoming solar radiation
Define long wave radiation
Outgoing terrestrial radiation whereby the earth’s surface has been heated by solar radiation
Briefly explain what is meant by a temperature inversion (3)
An increase rather than a decrease of temperature with height. They can form at the surface e.g. advection cooling or in the upper atmosphere e.g. stratosphere
Define dew point
The temperature at which relative humidity is 100%
Advection fog
Occurs when warm air flows over a cold surface and its temperature is chilled to dew point
Radiation fog
Occurs when the ground loses heat at night by long-wave radiation and chills the air to its dew point
Define mist
Cloud at ground level and occurs when visibility is between 1000-5000m and relative humidity is over 93%
Define fog
Cloud at ground level and occurs when visibility is below 1000m - dense fog occurs when the visibility is below 200m
2 ways condensation can take place
- Cooling of air
2. Addition of moisture into the atmosphere e.g. via sea breeze
When does temperature inversion happen?
When there are relatively calm (high-pressure) conditions and little mechanical turbulence from the wind that causes the air to mix
Why are temperature inversions important?
They influence air quality
When does temperature inversion act as a lid for pollutants?
Under high-pressure conditions and limited air movement - it causes the pollutants to remain in the lower atmosphere next to the Earth’s surface. The cold air at the surface is dense so it will tend to star at the surface.
Only when the surface begins to heat up and in turn warms the air above it, the warm air will be able to rise and with it any pollutants that it may contain
Where are temperature inversions common?
In depressions and valleys - cold air may sink to the bottom of the valley and be replaced by warmer air above it
When does the South Pole receive most insolation
December-January (summer solstice)
What does STHP stand for?
Subtropical high-pressure belts and it is permanent
Which has the greatest seasonal contrast in pressure - land or sea?
Land
How does a cold land mass influence pressure?
It causes high pressure