Explain why there is a surplus of solar energy in tropical latitudes and a deficit towards the poles (4)
1. Curvature of the earth + Angle of Incidence - The suns angle in the sky decreases towards the poles due to the curvature of the earth, which spreads the heat energy over a larger surface area- The suns rays are concentrated in the tropical latitudes as the intensity of insolation is greatest were rays strike vertically- Suns rays have less atmosphere to pass through at the tropics, so less of the suns energy is lost through reflection+ absorption by clouds, gas and dust2. Seasonal differences in isolation- Tilt of the axis (23.5o) results in the sun being higher in the sky between the tropics throughout the year, focusing energy on this latitude - There is no solar insolation at the winter solstices at the poles, resulting in 24-hour darkness, compared to the tropics that receive insolation throughout the year (constant) - this creates a large deficiency between the two 3. The Albedo effect- Albedo rates differ from darker forest surfaces at the tropics, where radiation is absorbed, in contrast the ice/snow caps in the polar areas reflect radiation
