Latitudinal effects
Intensity of insolation is not the same at all latitudes
Earth is roughly spherical, so insolation passing through 1 m2 screen
- Illuminates an area = 1 m2 where surface is perpendicular to radiation (near equator)
- Illuminates an area = 1 m2 x (1/sin45�) = ~ 1.4 m2 where surface is inclined ~45� to radiation (at 45� latitude)
- Illuminates an area = 1 m2 x (1/sin30�) = ~ 2 m2 where Earth�s surface is inclined ~30� to radiation (at 60� latitude),
Moving from the equator to the poles, insolation per unit area decreases uniformly