International Space Station perturbations

The largest perturbation in the inclination is 0.02 deg and its period is half the orbital period.

The largest perturbation in the semi-major axis is 6 km and its period is half the orbital period.

Here's the nodal precession due to the short-periodic perturbations on the osculating ascending node.
The two vertical dashed lines represent the orbital period.

Like the previous graph, also this graph shows the short-periodic perturbations, but this graph is for the inclination.