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 (23.5^o) 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