- Without the Sun’s presence, weather would not exist as it is the main source of energy.
- Global variations in solar radiation receipt lead to a constant imbalance of energy.
Factors affecting radiation receipt:
- Latitudinal variations. This energy is redistributed from areas of high solar radiation receipt at the equatorial and tropics, to areas of low solar radiation receipt near the poles – as it strives to reach a global equilibrium.
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- Diurnal (daily) variations exist i.e maximum receipt at midday when the Sun is at its greatest angle.
- Temporal (time dependent) variations exist due to the altering tilt of the Earth’s axis.
How does wind form?
- Inequalities in solar radiation over the Earth’s surface causes differences in air pressure, hence movement of energy as hot air rises and displaces cold air.
- The Earth’s rotation influences its direction by the Coriolis force – the deflection of motion to the right in the northern hemisphere and to the left in the southern hemisphere.
- Friction the Earth’s surface roughness including the presence of mountain belts, sand dunes, tower blocks etc, perturbs air flow causing it to converge into a low which rises above the obstruction or to diverge away into a high.
Properties of the atmosphere
Recommended website:
http://www.geol.umd.edu/~jmerck/geol100/lectures/33.html (Excellent diagrams and RS images displaying atmospheric stratification and global convection cells).
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