Desert Yellow vs Green Ochre

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Green Ochre is more saturated than Desert Yellow.

Can I use Green Ochre instead of Desert Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Green Ochre is more saturated than Desert Yellow.

Can I use Desert Yellow instead of Green Ochre?

The same difference applies the other way round: Desert Yellow is more muted.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.