parse_cdo_row/1 assumed cdo -outputtab,code,lev,value would always emit
numeric codes in the first column, but Debian's cdo 2.5.1 (the version
in the prod container) emits mixed output:
- 'codeNN' with a literal 'code' prefix for most GRIB1 parameters
- Short GRIB1 names for a few: 2tag2 (PRES sfc), saip (DPT 2m),
tpag10 (HGT)
Result: every row fell through to :error, yielding a 'no parseable
values' error and 986 discarded NarrFetchWorker jobs.
Fix: normalize the code token by stripping 'code' prefix when present
and mapping known 2.5.1 short names. UGRD/VGRD intentionally omitted
(no discard evidence yet) — comment documents the add-when-they-surface
plan.
Also exposed parse_cdo_outputtab/1 as @doc false for testability.
Post-2014 contacts with hrrr_status=:unavailable were being dispatched to
NARR, which 404s because NCEI's archive ends 2014-10-02. 14K of the 14.3K
candidates in prod are post-2014 — these are HRRR's responsibility.
- NarrClient.in_coverage?/1 returns true only inside 1979-01-01 → 2014-10-02
- narr_jobs_for_contact and maybe_enqueue_narr (contact_live) bail out of
coverage returning []
- BackfillEnqueueWorker.type_filter scopes :narr to qso_timestamp <
coverage_end so the cron doesn't keep picking post-2014 candidates
extract_profile_from_file shells out to cdo:
cdo -outputtab,name,lev,value -remapnn,lon=X_lat=Y <merged.grb>
parses the text output (varNNN ↔ NCEP GRIB1 param number lookup),
maps surface records to era5_profiles fields, builds the pressure
profile from each (TMP, HGT, SPFH) triple, and merges in the derived
fields from SoundingParams.derive/1. Returns the same attrs shape as
Era5BatchClient.build_profile_attrs/5 so the existing
bulk_insert_profiles path can ingest NARR rows unchanged.
fetch_profile_at picks records from a fetched inventory, byte-range
fetches each one into a per-record temp file, runs cdo -merge to build
a composite, calls extract_profile_from_file, and cleans up via
try/after.
Drive-by fix: ThetaE.dewpoint_from_spfh/2 returns Kelvin (its existing
test asserts that explicitly). Era5BatchClient was passing that
Kelvin value straight into "dwpc" (Celsius), which would then crash
SoundingParams.compute_refractivity_profile when it called Buck's
saturation-vapor-pressure equation with t=294 instead of t=21. The
bug never surfaced because era5_profiles is empty in production —
no ERA5 backfill has ever succeeded. Fixed in both era5_batch_client
and the new narr_client by subtracting 273.15 in the wrapper. Both
wrappers now have a comment pointing at the K→C conversion.
Test fixture test/fixtures/narr/narr_dfw_2010-06-15_12z.grb is the
spike-captured composite (1.1 MB — Lambert conformal projection
isn't sellonlatbox-subsettable so we can't shrink it further).
parse_inventory walks the wgrib1-format .inv text and returns a
{var, level} -> {byte_offset, length} index, computing each record's
length from the next record's offset (or file_size for the last one).
fetch_inventory does a GET on the .inv URL plus a HEAD on the .grb URL
to learn its size, then delegates to parse_inventory.
Both stubbable via Req.Test (config/test.exs adds narr_req_options
matching the existing era5_req_options / giro_req_options pattern).
Spike fixture at test/fixtures/narr/narr-a_221_20100615_1200_000.inv
backs the parser test — verifies the ("TMP", "2 m above gnd") and
("WVVFLX", "atmos col") records line up with the real bytes.
First slice of the NARR backfill client: url_for/1,
url_for_inventory/1, and snap_to_analysis_hour/1. Pure functions,
no network. Validates that NARR analyses only exist at 3-hourly
slots (00/03/06/09/12/15/18/21 UTC). The byte-range fetch and
cdo-driven point extraction land in follow-up commits per
docs/plans/2026-04-15-merra2-historical-backfill.md.
