The Atmosphere Flashcards
How far is the earth from the sun?
about 150 million km
What happens when the suns energy reaches earth?
It heats the earths atmosphere unequally
Results in pressure differences between the tropics and polar regions
What does the differences in pressure in earths atmosphere cause?
Wind and ocean currents
How does the sun heat the earth? (In the form of…)
In the form of short wave radiation called insolation
How does the earth heat the atmosphere?
In the form of long wave radiation called terrestrial radiation
Why doesn’t insolation reach the earths surface evenly?
Because the earth is a sphere
Which places receive more/less insolation?
More: places near the equator (warmer)
Less: places near poles (cooler)
Equator ANGLE
Suns rays hit the earth at a perpendicular angle, which spreads the energy over a smaller area.
Poles ANGLE
Suns rays hit the earth at an oblique angle which spreads the energy over a larger area
Equator AREA
The energy is spread out over a smaller area, so it is more concentrated
Poles AREA
The energy is spread out over a larger area so it is less concentrated.
Equator ATMOSPHERE
There is less atmosphere for the energy to pass through, so less energy is lost through scattering, absorption, reflection
Poles ATMOSPHERE
There is more atmosphere for the energy to pass through, so more energy is lost through scattering, absorption, reflection
Describe earth’s energy balance between the tropics
The angle of incoming solar rays is high
More energy is gained than lost so it is hotter (energy surplus)
Describe earth’s energy balance between the polar regions
The angle of incoming solar rays is low, so solar heating is low
More heat is reflected into space
More energy is lost than gained (deficit)
What’s the effect of the energy balance in polar and tropical regions?
Near 37 both north and south of the equator, a balance exists between energy gained and energy lost
How is the energy balance between the tropics and poles maintained?
Transfer of heat by wind (80%) and by water (20%)
How is a pressure gradient force formed?
The uneven heating of the earth causes pressure differences because warm air is less dense and rises.
This difference creates a pressure gradient force and causes wind to blow from regions of high pressure to regions of low pressure.
If the earth did not rotate on its axis a belt of low pressure would form in the hot equatorial regions while a belt of high pressure would form over the cold polar areas.
Describe single cell atmospheric circulation
The pressure differences causes cold, dry winds to blow from the polar high pressure to the equatorial low pressure.
Warm moist air rises at the equator. This warm air diverges in the upper atmosphere and flows towards the poles.
The air cools over the polar regions. It becomes more dense and sinks down back towards the surface.
Describe Coriolis Force
Because the earth rotates from west to east, the coriolis force deflects winds.
According to Ferrell’s law, winds are deflected to the right in the northern hemisphere and to the left in the southern hemisphere.
How do oceans contribute to heat transfer?
Water has a high specific heat which means oceans can absorb and store more heat than the land. The sea takes longer to warm up/cool down than the land.
Ocean circulation moves heat that is stored in the water from the low to the high latitudes.
Specific heat
This is the heat capacity; which is the amount of heat a specific material can hold compared to another material of the same mass
Discuss surface ocean currents
Warmer ocean currents carry the stored heat from the tropics towards the poles latitudes. Colder ocean currents from the higher latitudes carry water to the lower latitudes, where it is heated again.
In the northern hemisphere the surface currents mostly curve to the right and in the southern hemisphere they curve to the left (due to the coriolus force)
Discuss deep ocean currents
There is also a transfer of energy by deep ocean currents. This is due to differences in density of ocean water, depending on its temperature and salinity.
What do the surface ocean currents and deep ocean currents make up together?
The ocean conveyor belt
