The formula to calculate the Air Mass (AM) is:
\[ AM = \frac{1}{\cos(ZA)} \]
Where:
In this context, the air mass is a measure of how much atmosphere sunlight has to travel through to reach a point. It’s measured as a ratio of the amount of atmosphere relative to the amount of atmosphere sunlight has to travel through when it is directly overhead. For example, 1.25 air masses would be 25% more air mass than directly above.
A zenith angle is a measure of the angle from the surface to the line of the sun in the sky. It is measured only at sea level.
Let's assume the following value:
Using the formula to calculate the Air Mass:
\[ AM = \frac{1}{\cos(30^\circ)} \approx 1.15 \]
The Air Mass (AM) is approximately 1.15.