[Ncep.list.emc.fv3gfs_tickets] FV3GFS Ticket #22: Calculate vertical velocity in CHGRES

[FV3GFS Trac Ticket]

#22: Calculate vertical velocity in CHGRES
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 Reporter:  george.gayno@…  |      Owner:  george.gayno@…
     Type:  task            |     Status:  new
 Priority:  major           |  Milestone:
Component:  component1      |    Version:
 Keywords:  CHGRES          |
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 The GFS NEMSIO atmospheric restart files do not contain vertical velocity
 (in order to save disk space).  Therefore, when using current OPS GFS
 files, `CHGRES` will output missing vertical velocity (stored as zero).
 GFDL recommends that `CHGRES` output vertical velocity to improve model
 spin-up and forecast quality.

 According to Sajal, vertical velocity is computed in `POST` using these
 routines:
 *
 [https://svnemc.ncep.noaa.gov/trac/fv3gfs/browser/trunk/global_shared.v15.0.0/sorc/ncep_post.fd/CALVOR.f?rev=97077#L385
 caldiv]
 *
 [https://svnemc.ncep.noaa.gov/trac/fv3gfs/browser/trunk/global_shared.v15.0.0/sorc/ncep_post.fd/CALVOR.f?rev=97077#L657
 calgradps]
 *
 [https://svnemc.ncep.noaa.gov/trac/fv3gfs/browser/trunk/global_shared.v15.0.0/sorc/ncep_post.fd/GFSPOST.F?rev=97077#L904
 modstuff2]

 Incorporate these routines into `CHGRES`.

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Ticket URL: <https://svnemc.ncep.noaa.gov/trac/fv3gfs/ticket/22>
fv3gfs <https://svnemc.ncep.noaa.gov/trac/fv3gfs>
NGGPS FV3GFS Development