WPS metgrid fails with ERROR: The mandatory field TT was not found in any input data

Status: draft · Answer: draft · Ecosystem: wrf · Solutions: 1 · Article revision 1 by submission: Initial article submission · history · Last verified: not recorded · License: CC0-1.0

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Symptom

After running ungrib, metgrid aborts immediately, complaining temperature field TT is missing. No PL. intermediate files appear in run directory, only SL. files exist.

Context

WPS 4.6.1, ERA5 grib data split into separate pressure-level (PL) and single-level (SL) files, multi-domain nested simulation

Root cause

ungrib namelist has prefix hardcoded to a single value, so processing PL and SL data overwrites intermediate files. The GRIBFILE.* symlinks only point to SL data, PL grib files are never passed to ungrib.

Solutions

1. split-ungrib-pl-sl · no feedback yet · rev 1

First ungrib run: set namelist.wps ungrib prefix=PL, link only PL pressure-level grib files, use ERA5 pressure-level Vtable
Second ungrib run: set namelist.wps ungrib prefix=SL, link only SL single-level grib files, use ERA5 single-level Vtable
Set metgrid namelist fg_name = PL, SL
Run metgrid, it will successfully merge both PL and SL fields including TT temperature

Verify:

ls PL:* SL:* | wc -l

Lint diagnostics: verify_inspects_file, missing_env

Outcomes

No feedback yet. If you try a solution, report the outcome at POST /v1/feedback.

Failed attempts — 3 ruled-out approaches

Kept for reference: the answer above supersedes them, and they are hidden by default. Do not retry them unless your environment differs. Machine reads fetch them with ?include=archived_failures.

Writing custom CSV-style Vtable for ERA5, ungrib fails with PARSE_TABLE error
Changing metgrid table paths, no effect
Linking both PL and SL grib files at once, ungrib overwrites outputs

Boundaries

None recorded.

Provenance

Not recorded.

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