OK, I’m sure there is a mind-numbingly obvious answer to this, but my sleep-addled brain hasn’t been able to come up with it.
My understanding of why it’s hot in the Summer and cold in the Winter (at least here in the northern hemisphere) is that it has to do with the fact that the Earth as a 23 degree tilt to its axis. In the summertime, the northern hemisphere is tilted toward the sun, meaning more sunlight per day, meaning more heat. [And yes, I know that it has nothing to do with how close the Earth is to the sun, since the Earth is actually further from the sun in the Summer than in the Winter.]
If all that is true, howrever, why isn’t the North Pole the hottest place on Earth in the summertime? Isn’t it receiving more direct sunlight than any other place on the planet during that period? I have heard that the sun never sets in the summertime way up north – wouldn’t 24 hours of daylight make things a little toasty? What am I missing here? Is it the presence of all the stored ice from the Winter? Is it the weather patterns? Is the sunlight not as “direct” as I am assuning it to be? Or does Santa Clause just have a very large air conditioner?
The sun doesn’t rise very high above the horizon even during summer at the north pole. The earth’s tilt results in the pole getting more light in the summer than the winter, but even at the height of summer, the pole receives much less energy per square meter than do lower latitudes simply because the land up there does not directly face the light source.
Ah. That would definitely qualify as a crucial piece of information about which I was previously unaware. I just assumed the sun would be almost directly overhead most of the day…
The axial tilt of the earth is not that severe. If it had about 60 degrees of tilt then it wold be much warmer at the pole with the sun just circling high in the sky for months at a time.
The latitude’s where the sun can be directly overhead are bounded by the Tropics of Cancer and Capricorn. Those of course are around 23 degrees from the Equator. Therefore those regions get the most sunlight year round and are obviously the hottest.
If you live outside that range, e.g., MA, you should have noticed that the sun never gets directly overhead you. So how could it ever get directly overhead a location farther north?
The amount of heat reaching the surface is proportional to the sine of the sun’s height for those periods where the sun is above the horizon. From about May 25th through July 15th, the north pole does receive more sun than any other place on earth even though the sun is only 20+ degrees above the horizon.
The surface at the poles is white and reflects most of the sunshine back into space.
I was in Deadhorse, AK, lat June 1st. The Arctic ice was still right up to the shore, By late July, the southern limit of the ice retreats a few nundred miles towards the pole.
