CDO

Hello,

I have a soil temperature file.
I have a file of soil temperatures that I would like to linear interpolate to 0.01, 0.1, 0.5, 1.0 m...... because the data itself does not have the right division of the soil layers for research needs!
After reading the user guide of CDO, I found that both "intlevel" and "intlevel3d" can be used for interpolation. However, "intlevel" is a linear horizontal interpolation, while "intlevel3d" is a linear level interpolation from/to 3d vertical coordinates.I am not sure which method should be used for soil temperature.

Which interpolation method, "intlevel" or "intlevel3d", can be used to interpolate the soil temperature?
If "intlevel3d", how should the input icoordinate and ifile2 files be generated?

Thank you very much!