I am using vertintegral, from version ioapi3.1, and it gives me the error that ZF and DENS are not found in the METCRO3D file:
 "METCRO3D" opened as OLD:READ-ONLY   
 File name "/pln10/STATE_CMAQ/CMAQv5.0.2/data/aqmp16/mcip/carb_met/METCRO3D_2012_07"
 File type GRDDED3 
 Execution ID "mcip"
 Grid name "METCRO_State_107"
 Dimensions: 97 rows, 107 cols, 18 lays, 15 vbles
 NetCDF ID:    131072  opened as READONLY            
 Starting date and time  2012183:060000 (6:00:00   July 1, 2012)
 Timestep                          010000 (1:00:00 hh:mm:ss)
 Maximum current record number       749
  Variable ZF not found in met file  METCRO3D
 Variable DENS not found in met file  METCRO3D
 
 *** ERROR ABORT in subroutine VERTINTEGRAL
 Fatal setup error(s)
But the variables are in the file (see below). Any clue of what could be happening?
netcdf METCRO3D_2012_07 {
dimensions:
TSTEP = UNLIMITED ; // (749 currently)
DATE-TIME = 2 ;
LAY = 18 ;
VAR = 15 ;
ROW = 97 ;
COL = 107 ;
variables:
int TFLAG(TSTEP, VAR, DATE-TIME) ;
TFLAG:units = “<YYYYDDD,HHMMSS>” ;
TFLAG:long_name = "TFLAG           " ;
TFLAG:var_desc = "Timestep-valid flags:  (1) YYYYDDD or (2) HHMMSS                                " ;
float JACOBF(TSTEP, LAY, ROW, COL) ;
JACOBF:long_name = "JACOBF          " ;
JACOBF:units = "M               " ;
JACOBF:var_desc = "total Jacobian at layer face                                                    " ;
float JACOBM(TSTEP, LAY, ROW, COL) ;
JACOBM:long_name = "JACOBM          " ;
JACOBM:units = "M               " ;
JACOBM:var_desc = "total Jacobian at layer middle                                                  " ;
float DENSA_J(TSTEP, LAY, ROW, COL) ;
DENSA_J:long_name = "DENSA_J         " ;
DENSA_J:units = "KG/M2         " ;
DENSA_J:var_desc = "J-weighted air density: MM5-total dens, WRF-dry dens                            " ;
float WHAT_JD(TSTEP, LAY, ROW, COL) ;
WHAT_JD:long_name = "WHAT_JD         " ;
WHAT_JD:units = "KG/(M*S)        " ;
WHAT_JD:var_desc = "Jacobian and density weighted vert contravariant-W                              " ;
float TA(TSTEP, LAY, ROW, COL) ;
TA:long_name = "TA              " ;
TA:units = "K               " ;
TA:var_desc = "air temperature                                                                 " ;
float QV(TSTEP, LAY, ROW, COL) ;
QV:long_name = "QV              " ;
QV:units = "KG/KG           " ;
QV:var_desc = "water vapor mixing ratio                                                        " ;
float PRES(TSTEP, LAY, ROW, COL) ;
PRES:long_name = "PRES            " ;
PRES:units = "Pa              " ;
PRES:var_desc = "pressure                                                                        " ;
float DENS(TSTEP, LAY, ROW, COL) ;
DENS:long_name = "DENS            " ;
DENS:units = "KG/M3         " ;
DENS:var_desc = "density of air: MM5-total density, WRF-dry density                              " ;
float ZH(TSTEP, LAY, ROW, COL) ;
ZH:long_name = "ZH              " ;
ZH:units = "M               " ;
ZH:var_desc = "mid-layer height above ground                                                   " ;
float ZF(TSTEP, LAY, ROW, COL) ;
ZF:long_name = "ZF              " ;
ZF:units = "M               " ;
ZF:var_desc = "full-layer height above ground                                                  " ;