Hi,

 

First of all, cause this is my first message, I say hello to everyone and I would like to apologize for my english, it is not my native language.

 

I am looking for a software that could give me the amount of solar energy received on earth according to latitude, longitude, altitude and day of the year.

 

I think that such software exist but I don't where I can find it.

 

Many thanks in advance.

Luminosity of the Sun = 4 * 10 26 watts

 

The formula for the surface area of a sphere is: 4 pi r^2

 

A sphere with a radius equal to the Earth / Sun distance would have a surface area of:

4*3.14*150000000000^2= 2.81E+23 square meters.

 

So each square meter on Earth receives

 

4e26 / 2.81e23 = 1442 watts of energy.

 

Just Google for more accurate values for Solar Luminosity and Earth / Sun distance. Earth is a little closer to the Sun in Winter, so you could take this into account too.

 

Then for latitude and time of day, you have to figure out the Sun's altitude in the sky. If it is overhead, at 90 degrees, then sin(90) = 1. A square meter at this point would receive 100% of the 1442 watts. But if the Sun were only 45 degrees high, then it would receive sin(45)=0.707 or 70.7% of 1442 watts. If the Sun were setting on the horizon, then sin(0) = 0, it would receive 0% of the 1442 Watts.

 

There's a free program called Stellarium (Google to find the download page) that will tell you the Sun's altitude in the sky as well as the Earth / Sun distance for any given instant. Then you could feed these numbers into the above formulas.