Do different parts of the world receive different amounts of sunshine during the year? Ignore clouds, or consider only what is received either on the cloud tops or surface, whichever is available. Is it the same at the poles as at the equator? ... the northern and the southern hemispheres?

Consider two interpretations of the above: (1) number of hours per year that the sun is up, (2) the total insolation (total solar energy received per unit of area of the ground) received during the year, weaker when the sun is low near the horizon than when it is high in the sky.

Hmmm, based on my limited understanding of geography and the real world:

At the equator every day has twelve hours sunshine
At the poles there are 6 months of light and 6 months of darkness.
At the points in between summer days have more than 12 hours of sunshine, winter days have less than 12 hours of sunshine and at each equinox there are exactly 12 hours sunshine.

So my guess on the first question is that every point on the globe has the same number of hours sunshine through the year.

On the second question...

At the equator it's hot.
At the poles it's cold.

Assuming that the atmosphere has roughly the same insulating properties at the pole and the equator, then the equator must clearly receive more energy from the sun than the poles. Presumably this relates to the average angle of the sun which is almost 90deg at the equator and almost 0deg at the poles.

So my guess for question 2 is that the insolation increases as one moves from the poles to the equator.

No rocket science, no equations, just good old fashioned common sense!

Posted by fwaff on 2003-03-09 22:07:16