Reader Timothy writes in with a question:
It seems that the north pole would get more daylight during the summer solstice than the equator does during an equinox. During the summer solstice, the north pole would get the equivalent of (24hrs)sin(23.5 ° ) = 9.57 hours of sunlight from directly overhead (the zenith). During the equinox, the equator would get the equivalent of (12 hrs / pi radians) ∫ sin θ d θ (integrating from zero to pi) = 7.64 hours of sunlight from the zenith. We only integrate from zero to pi, when the sun is above the horizon.
I am curious as the reasons why the north pole would be colder even around the summer solstice than the equator around an equinox. I presume factors would include heat capacity of water and ice, albedo of ice, wind patterns, attenuation of light in the atmosphere, etc.
In other words, in the perpetual daylight of an Alaskan (or polar) summer, the total energy being pumped into each square meter is pretty hefty considering there’s no night to reduce the average. But on the equator with the sun directly overhead at noon, the sunlight will be diluted by the fact that not only is the sun’s angle constantly changing but for fully half of the 24-hour day there’s no light at all.
But pretty clearly the Equatorial spring is hotter than the polar summer. What gives?