Figure 1 – effect of angle of inclination on Insolation

♤ The sun’s rays with small angle traverse more of the atmosphere than rays striking at a large angle. Longer the path of sun’s rays, greater is the amount of reflection and absorption of heat by atmosphere. As a result the intensity of insolation at a place is less (figure 1). Angle of inclination of solar radiation depends on latitude of a place. The higher the latitude the less is the angle they make with the surface of the earth resulting in slant sun rays. Figure 1 show the winter Solstices in the Northern Hemisphere where angle of inclination is zero at 66 ½ N latitude.