Why is the net radiation smaller at the tropics than at the Ecuator?

Question

At the tropics, it's bigger than 200 kcal/cm2. At the Ecuator, it's 180 kcal/cm2. What's the reason of this? Explain thoroughtly.

Answer 1

The angle the Sun strikes the Earth at the tropics is more acute than at the equator.

Answer 2

cause of the difference in angle from the north pole and the magnetic pole 27,5 degrees
the earth is not exactly at 90 degrees from the sun