When the sun's rays strike Earth's surface near the equator, the incoming solar radiation is more direct. Therefore, the solar radiation is concentrated over a smaller surface area, causing warmer temperatures. The Sun does not heat all parts of the Earth to the same extent; the Equator receives more energy than the poles. This is because the Earth is round and spins leaning over in relation to the Sun. The sun's rays are strongest at the equator where the sun is most directly overhead and where UV rays must travel the shortest distance through the atmosphere. The Northern Hemisphere receives the maximum intensity of the sun's rays, while the angle of sunlight decreases in the Southern Hemisphere. Most of the energy in the Earth system comes from just a few sources: solar energy, gravity, radioactive decay, and the rotation of the Earth. Solar energy drives many surface processes such as winds, currents, the hydrologic cycle, and the overall climate system. The Earth absorbs most of the energy reaching its surface, a small fraction is reflected. In total approximately 70% of incoming radiation is absorbed by the atmosphere and the Earth's surface while around 30% is reflected back to space and does not heat the surface. Due to the spherical shape of the Earth, sunlight falls on different parts at different angles. Direct and focused sun rays falls on the equator and hence, the regions here are hotter and warmer.

The sun's rays are the most concentrated around the equator. Moving north or south of the equator, the sun's rays are spread over a larger area, so each square meter of Earth's surface receives less solar energy. This is because of the angle of the sun's rays as they strike Earth's curved surface. The equator gets the most direct sunlight year-round. The angle of sunlight hitting the equator is more direct than it is at the poles, so the poles receive less direct sunlight. The Northern Hemisphere receives the maximum intensity of the sun's rays, while the angle of sunlight decreases in the Southern Hemisphere. The Sun does not heat all parts of the Earth to the same extent; the Equator receives more energy than the poles. This is because the Earth is round and spins leaning over in relation to the Sun. Because Earth is a sphere, not all part of the Earth receives the same amount of solar radiation. More solar radiation is received and absorbed near the equator than at the poles. Near the equator, the Sun's rays strike the Earth most directly, while at the poles the rays strike at a steep angle.The Sun's rays strike Earth's surface most directly at the Equator. Near the poles, the Sun's rays strike the surface at a slant. This spreads the rays over a wide area. The more focused the rays are, the more energy an area receives. Due to the spherical shape of the Earth, sunlight falls on different parts at different angles. Direct and focused sun rays falls on the equator and hence, the regions here are hotter and warmer. When the sun's rays strike Earth's surface near the equator, the incoming solar radiation is more direct. Therefore, the solar radiation is concentrated over a smaller surface area, causing warmer temperatures. At latitudes near the equator (0 ° 0\degree 0°), the Earth's surface is almost directly perpendicular to the angle of the sun's rays. In these regions, solar radiation is intense because the sun's energy is concentrated over a small surface area.

Just higher power density if radiation is perpendicular (cosine of incident angle) and thinner layer of atmosphere to pass, if radiation is perpendicular to atmosphere.

Thanks Dr. Jan Balaz for participating in the discussion.

In the latitudes between 23.5 degrees North and 23.5 degrees south, the Sun passes directly overhead twice each year. The more slanted the sun's rays are, the longer they travel through the atmosphere, becoming more scattered and diffuse. Because the Earth is round, the frigid Polar Regions never get a high sun, and because of the tilted axis of rotation, these areas receive no sun at all during part of the year. Higher latitudes receive less solar radiation because the sun's rays stride the Earth's surface at a less direct angle. This spreads the same amount of solar energy over a larger area, resulting in lower temperatures. More solar radiation is received and absorbed near the equator than at the poles. Near the equator, the Sun's rays strike the Earth most directly, while at the poles the rays strike at a steep angle.The Sun's rays strike Earth's surface most directly at the Equator. Near the poles, the Sun's rays strike the surface at a slant. This spreads the rays over a wide area. The more focused the rays are, the more energy an area receives. At latitudes near the equator (0 ° 0\degree 0°), the Earth's surface is almost directly perpendicular to the angle of the sun's rays. In these regions, solar radiation is intense because the sun's energy is concentrated over a small surface area. When the sun's rays strike Earth's surface near the equator, the incoming solar radiation is more direct. Therefore, the solar radiation is concentrated over a smaller surface area, causing warmer temperatures. Due to the spherical shape of the Earth, sunlight falls on different parts at different angles. Direct and focused sun rays falls on the equator and hence, the regions here are hotter and warmer. As you can see above, because of the curve of the Earth a sunbeam of Insolation hitting the Earth at higher latitudes has to spread out over a larger surface area than one reaching the Equator. Thus lowering the amount of Insolation per km2 in more Northerly and Southerly latitudes.At higher latitudes, the angle that the sun's rays hit Earth is lower due to Earth's curved shape. This causes the sun's energy to be spread over a larger surface area, which results in lower overall temperatures north and south of the equator. The equator receives the most direct and concentrated amount of sunlight. So the amount of direct sunlight decreases as you travel north or south from the equator. Look at the diagram of Earth above that shows different latitudes. The sun's rays are the most concentrated around the equator. Moving north or south of the equator, the sun's rays are spread over a larger area, so each square meter of Earth's surface receives less solar energy. This is because of the angle of the sun's rays as they strike Earth's curved surface. The Northern Hemisphere receives the maximum intensity of the sun's rays, while the angle of sunlight decreases in the Southern Hemisphere. The Sun does not heat all parts of the Earth to the same extent; the Equator receives more energy than the poles. This is because the Earth is round and spins leaning over in relation to the Sun.