# Ice Water Content from GFS file

I am working my way through this paper: http://downloads.hindawi.com/journals/amete/2017/8707234.pdf

Equations 10 and 11 require the ice water content. I can't find it in the GFS grib2 file variables. Did I miss it, or is possible to derive it from the available information. Right now I have pressure, temperature, and relative humidity.

There is a parameter ice water mixing ratio in the gfs.t<hour>z.pgrb2.0p25.f<step> file given at isobaric levels.