Hi Robert,

The RUC2 uses a "hybrid isentropic-sigma" veritcal coordinate
system, with 40 levels.  Documentation can be found at  One of the links will take you
to a RUC Techincal Procedures Bulletin pdf file, which
explains the system in more detail.


Kevin Tyle, Systems Administrator               **********************
Dept. of Earth & Atmospheric Sciences           ktyle@xxxxxxxxxxxxxxxx
University at Albany, ES-235                    518-442-4571 (voice)
1400 Washington Avenue                          518-442-5825 (fax)
Albany, NY 12222                                **********************

On Sun, 14 Apr 2002, Robert Mullenax wrote:

> I downloaded one of the RUC2 grids from
> and passed it through dcgrib.  The grid is:
> ruc2.t23z.bgrbf01
> I looked at the resulting GEMPAK file and the vertical coordinate
> is labeled HYBL, and ranges from 40 to 1.  Does anyone know
> what that is, and what units?
> Thanks,
> Robert Mullenax

  • References:
    • HYBL
      • From: Robert Mullenax