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The points which, instantaneously, receive the least radiation during daylight hours must be (I assume) those that lie tangent to the Sun rays. These points rotate, so there's a whole circle of them surrounding each geographical pole. These points are not colder than the poles because (again, I assume) the radiation they receive is higher on average, although (instantaneously, during the day) the lowest anywhere on Earth.

So, the points on Earth that receive the least radiation on average must be within those circles. Which are they; are they the poles?

I should perhaps add that I am interested in the version of the problem that idealizes away from complications having to do with cloud cover or other atmospheric effects.

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  • $\begingroup$ so are you asking if any point of our planet have more or less than 12 hrs of average sunlight per year.a good place for information is this site timeanddate.com $\endgroup$ – trond hansen Mar 2 at 13:12
  • $\begingroup$ @trondhansen, thanks for your comment! Not just sunlight, but also radiation, e.g., watt per sq meter on, say, a yearly average. This quantity must look very different in the Equator and in near the poles, right? $\endgroup$ – Schiphol Mar 2 at 14:31
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    $\begingroup$ sciencedirect.com/topics/earth-and-planetary-sciences/… may or may not be helpful. As your tag notes, the word to google for is "insolation". If you want to allow for clouds and such globalsolaratlas.info may help, but only covers limited latitudes. $\endgroup$ – Barry Carter Mar 2 at 17:55
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    $\begingroup$ @Schiphol this is not an answer but i think the central parts of antarctica gets about 60 hrs less sunlight than the central arctic does in a year.en.wikipedia.org/wiki/Sunshine_duration i know too little about this to make an answer. $\endgroup$ – trond hansen Mar 2 at 18:26
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On an average those would be the poles. As you correctly pointed out, due to the tilt of the Earth's axis, there are large areas that receive very little and sometimes no sunlight at all and those change throughout the year. But on an average, poles are the ones that get the least amount of solar radiation.

For example, see this paper and in particular have a look at figures 2.6 and 2.7. The last of the two figures, which I will link here shows the graph of annual mean insolation as a function of latitude.

enter image description here

Here it's obvious that poles do receive the least amount of radiation on an average. But this is the idealized case, i.e. insolation at the top of atmosphere.

On the other hand, if you do take prevailing atmospheric conditions into account then it's a competition between the area between Spitzbergen and Iceland in the North and areas just off the coast of Antarctica in the South. Taken from Wikipedia article on Solar Irradiance the top picture shows top of the atmosphere insolation and the bottom one - ground-level insolation.

enter image description here

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    $\begingroup$ This is exactly what I needed, thanks. The change in slope around latitude ±70 in the first figure is what I thought might have counterintuitive consequences for the avg solar flux. Disappointed to see that it doesn't :) $\endgroup$ – Schiphol Mar 3 at 10:14

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