2: Energy and Radiation

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Figure \(\PageIndex{1}\): Sunrise over South America (Courtesy NASA)

Solar radiation is the source of energy that drives most environmental processes acting at the surface of the Earth. The spatial variation of energy affects the spatial variation of temperature, wind, and moisture which determine the geography of soils, vegetation, climate and landforms. The awesome power of hurricanes and tornados is driven by the heating of water and subsequent heat release during condensation. Unequal heating of the Earth's surface creates wind that heaps sand into great dunes.

The most noticeable global pattern is the seasonal change in where regions of positive and negative net radiation occur. Regions of positive net radiation and energy gain occur during the summer months, and thus shifts from northern to southern hemisphere. Large positive net radiation appear in the tropics, large negative at the poles. Why does this spatial and temporal pattern in net radiation occur and what are the implications? Will this pattern change in the future?

Learning Objectives

By the end of the chapter you should be able to:

Compare and contrast energy, heat and temperature.
Define sun angle, solar declination, day length, and describe their geographical variation through the seasons.
Calculate the noon sun angle for any latitude on the solstices and equinoxes.
Explain the global pattern of insolation, net radiation, sensible heat and latent heat.

See if you are prepared for this chapter by "Getting Ready for Chapter 4: Energy and Radiation".