Environmental Engineering Reference
In-Depth Information
Figure 9.8
The physical processes and properties that govern
the global climate and its changes.
Figure 9.9
Variations in sunspot frequencies, 1610-1999.
Source: Data from http://www.oma.be
7 per cent between perihelion and aphelion. If Earth is at the perihelion during the
northern hemisphere winter it will receive more energy and therefore be warmer than if it
were at the aphelion at that time. The time of year at which Earth is nearest the sun does
