BIOL 1108 Lecture Notes - Lecture 43: Biome, Northern Hemisphere, Energy Density
Document Summary
The latitudinal difference in incoming solar energy density explains why earth"s surface is hotter at the equator and cools towards the poles. At the equator, solar energy strikes earth directly, resulting in high influx of energy per unit area. At high latitude, incoming solar energy strikes earth at an angle, resulting in lower fluxes of energy per unit area. Solar radiation, wind, and ocean currents, and topography determine the distribution of major climatic zones on earth. Because of earth"s tilt, the northern hemisphere receives more solar energy per unit area in july than at other times of the year. Rising and descending air organizes the atmosphere into a series of cells from the equator to the poles. High temperatures warm air near the equator, and because of its lower density, the warm air rises. As air rises and spreads outward toward the poles, it cools, eventually becoming dense enough to sink back to the surface.
