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).
Graham McIntire
e5528d0135