Create two x axes, but one of them is a log scale

Hello all,

I have a bit of a unique problem that I haven't been able to find a solution for. I have a semilog set up right now so that I have a linear variable (windspeed) on the y and a log variable (mass flux) on the x. Each mass flux value has several windspeed values attributed to it. Each mass flux also has a diameter attached to it, and that's what I'd like to plot on the top x axis. I'd like it so the linear diameter values can line up exactly with the mass flux values. Short of just adding in these numbers to the top manually in Illustrator, is this possible?