UPP Online Tutorial for UPPV4.1 | Control Files for GRIB2 > GRIB2: Variable and level modifications

To output a field, the body of the postcntrl.xml file needs to contain an entry for the appropriate variable and include at least the shortname, pname, level, and scale, with additional tags as deemed necessary. If a field is not in your postcntrl.xml but it is available for output, you may simply copy that parameter from the post_avblflds.xml.

Controlling which levels unipost outputs

To modify which levels to output, the values in the level tag will need to be edited to reflect the desired output levels for that variable. If the variable is defined over a specific layer, then both the level (first level of the layer) and level2 (second level of the layer) tags will need to be edited.

The list below details which variables are available for output for a variety of fields.

  • For isobaric output, 47 levels are possible from 2 to 1000 hPa (2, 5, 7, 10, 20, 30, 50, 70 mb and then every 25 from 75 mb to 1000 mb). Modifications to which isobaric levels are possible can be made in /UPPV4.1/src/unipost/CTLBLK.f.
    • Modify the variable LSMDEF to change the number of pressure levels in your array (e.g. LSMDEF=47)
    • Modify the SPLDEF array to change the values of pressure levels, i.e. (/200.,500....97500.,100000./)
  • For model-level output, all model levels are possible, from the highest to lowest
  • For soil levels, layers or levels depend on your LSM:
    • Noah LSM soil layers are 0-10, 10-40, 40-100, and 100-200 cm.
    • RUC LSM soil levels are 0, 1, 4, 10, 30, 60, 100, 160, and 300 cm. For the RUC LSM, it is necessary to turn on 5 additional levels in the wrf_cntrl.parm to output 9 instead of 4. (For the old RUC LSM, there are only 6 layers, and if using this, you will need to change RUC LSM from 9 to 6 in the WRFPOST.f routine).
    • Pliem-Xiu LSM layers are 0-1 and 1-100 cm.
  • For low, mid, and high cloud layers, the layers are ≥642 hPa, ≥350 hPa, and <350 hPa, respectively.
  • For PBL layer averages, the levels correspond to 6 layers with a thickness of 30 hPa each.
  • For flight levels, the levels are 30, 50, 80, 100, 305, 457, 610, 914, 1524, 1829, 2134, 2743, 3658, 4572, 6000 and 7010 m.
  • For AGL radar reflectivity, the levels are 4000 and 1000 m.
  • For surface or shelter-level output, specify the surface level for the particular variable. 

For a list of available fields for GRIB2, see the GRIB2 Table