Processing math: 100%

Air Mass Calculator

Formula

The formula to calculate the Air Mass (AM) is:

$AM = \frac{1}{\cos(ZA)}$

Where:

$AM$ is the Air Mass
$ZA$ is the Zenith Angle

What is an Air Mass?

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.

What is a Zenith Angle?

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.

Example Calculation

Let's assume the following value:

Zenith Angle (ZA) = 30 degrees

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.