Atmo: Energy Budget & Temp Variations Flashcards
What is scattering?
Some insolation that passes through the earth’s atmosphere will be scattered as gases and dust particles in the atmosphere redirect this energy via scattering. Shorter waves are scattered more than longer waves.
What is reflection?
When reflected, the radiation is returned to space in short wave form. The amount of energy that gets absorbed by the surface depends on the colour and type of surface.
Light coloured surface, smooth shiny surface: reflect more
The amount of insolation received by a surface is dependent on its _________
Albedo - associated with surface reflectivity.
Ice: High albedo
Dense forest: Low albedo
Greatest variability is over water.
Describe absorption
Insolation can also be absorbed by the atmosphere which thereby gains heat and warms up. Gases inc. water vapour as well as clouds, dust and haze in the atmosphere absorb certain wavelengths. Oxygen removes most short wave radiation and ozone absorbs longer wave radiation.
What is the natural greenhouse effect?
Our atmosphere is largely transparent to short-wave and more absorptive to long wave radiation. This gives rise the the green house effect whereby gases such as carbon dioxide & water vapour warm up the earth by absorbing and re emitting radiation.
What are the 3 reasons for the latitudinal difference in insolation amount?
1) beam spreading
2) more atmosphere to pass through
3) albedo
What is the energy surplus in the equator?
About 2.4 times more solar energy is available at the equator than the poles
What is the global energy balance?
The balance between the amount of incoming shortwave solar radiation (insulation) and the amount of long wave terrestrial radiation so that net radiation is zero.
How does beam spreading affect amount of insolation received?
At the tropics, the sun is directly overhead at the sub solar point and insolation is the most concentrated. There is less beam spreading and the amount of radiation received is the highest. With increasing latitude, solar radiation reaches the surface at a lower angle. More beam spreading means less solar radiation is received at the poles.
(Draw diagram)
What is the second reason for the latitudinal difference in insolation amount?
Insolation has more atmosphere is pass through near the poles due to low angle of approach. Hence, more energy is absorbed, scattered or reflected than over equatorial areas, resulting in less insolation received at the poles. (Draw diagram)
What’s the 3rd reason for the latitudinal difference in insolation amount?
Albedo is higher in polar regions since snow and ice are very reflective. Albedo is lowest at equator she to vegetation cover. Results in heat surplus in tropics and deficit at poles.
What factors affect regional temperature variations?
POACA
- proximity to sea
- ocean currents
- altitude
- cloud cover
- aspect
How does proximity to sea affect temperatures? Explain.
Areas located near the sea with a coastal influence have milder seasons/ less seasonal contrast.
1) specific heat capacity of water is 5times as great as land, water cools down and heats up slower than land
2) radiation received at the surface of a waterbody can penetrate water and distribute its energy throughout a very large mass. Insolation absorbed by land heats only a very thin, opaque surface layer
3) water evaporates which absorbs latent heat, hence less warming occurs
4) water can be mixed vertically and horizontally
How does ocean currents affect temperatures?
Warm currents carry large amounts of energy, heat is transferred to the atmosphere and promotes high air temperatures. Cold currents reduces summer temperatures.
Name 1 warm current and 1 cold current
Gulf Stream and North Atlantic Drift
Labrador Current
