Measurement · Physical Oceanography · µmol/kg

DO sensor 2 (uncorrected)

The registry carries no authored label for this measurement, so the name above is the canonical series' own description in metadata/measurement_type.csv (variable.csv holds the authored labels, five today).

NERC P01 DOXMZZXXP06 units KGUM umol/kgkey oxygen_umol_kg_2 series oxygen_umol_kg_2

328,417
values: 46
flagged: 4,806
sampling events: 1999–2026
years: 1
dataset: 1–3,630 m
depth: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Oct · Nov
seasons

Heads-up 46 of these 328,417 values (under 0.1 %) are flagged by their provider as questionable or bad. The Explorer, the climatology and its anomalies leave them out; do the same when you read the data yourself (cc_qual_ok_sql() in calcofi4r, qual_ok_sql() in calcofi4py).

Measured in

CTD Cast Files 328,417 values · 4,806 sampling events · 1999–2026 · 1–3,630 m · 90 grid cells · 64 cruises

series oxygen_umol_kg_2 · source column ox2u_m · flag column ox2q 46 flagged

One row per series, one cell per year, darker with more values — the same strip the front door draws per dataset and a species page draws per taxon. Each row is one dataset's own measurement_type; the label is written once, in the title above.

By depth

Values per depth band at the release grain, one thin bar per series. The bands are the record's own (0-10 … 2000+ m).

By month

Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in the months the ships sail.

Range & quality

bounds: The registry declares 0 … 700 µmol/kg for oxygen_umol_kg_2; a value outside it is dropped at the ingest (drop_out_of_bounds()).
observed: CTD Cast Files oxygen_umol_kg_2 0.008 · median 102.6 · 667.1 µmol/kg (5th–95th percentile 15.45–249.4)
flags: CTD Cast Files oxygen_umol_kg_2 ox2q on 46 of 328,417 rows: 8 44 · 9 2; qual_ok keeps 328,371. The codes are this dataset's own vocabulary, uninterpreted.
baseline: A monthly climatology exists for this measurement (the release's climatology table: 1993–2013, dataset × grid cell × calendar month × 10 m bin), so the Explorer can draw anomalies against it rather than values.

Related measurements

Bottle dissolved oxygen oxygen_btl_umol_kg · CTD Cast Files · 1993–2025 · 127,192 values · P01 DOXMZZXX the same quantity from the CTD files' own bottle samples — plausibly the same physical bottles, so merging them would count the bottle dataset twice
Dissolved oxygen (µmol/kg) oxygen_umol_kg · oxygen_umol_kg_ave_sta_corr · Hydrographic Bottle · CTD Cast Files · 1949–2025 · 1,011,741 values · P01 DOXMZZXX one sensor of the pair beside the mean the file publishes
DO sensor 1 (uncorrected) oxygen_umol_kg_1 · CTD Cast Files · 1993–2026 · 670,785 values · P01 DOXMZZXX the other sensor of the pair, logged alongside
Reported oxygen (pre-QC) r_oxygen_umol_kg · Hydrographic Bottle · 1949–2021 · 690,698 values · P01 DOXMZZXX the source's own reported value before its QC — this page is the QC'd twin

The same quantity from another platform or another kind of sample, each its own page and never merged into this one: a dataset's own bottle samples would count that dataset twice, an underway intake is not a cast, and a replicate is not a mean. The reason is the record's (related[].why).

Ways in

Explorermaps, sections and time series of this measurement — opens prefilled
https://calcofi.io/explore/?var=oxygen_umol_kg_2
Explorer · a depth section vs normalthe newest cruise's section against the climatology baseline
https://calcofi.io/explore/?lens=section&var=oxygen_umol_kg_2&anom=1
db-querySQL in your browser — the shell opens with this query
https://calcofi.io/db-query/?sql=SELECT+%2A+FROM+__TBL%3Aobs_env__+WHERE+measurement_type+%3D+%27oxygen_umol_kg_2%27+LIMIT+100%3B
ERDDAP · CTD Cast FilesCalCOFI's own server, the CTD Cast Files table constrained to this series
https://erddap.calcofi.io/erddap/tabledap/calcofi_ctd-cast.html?&measurement_type=%22oxygen_umol_kg_2%22
Parquetobs_env is partitioned by measurement_type in the content-addressed store — resolved through the release catalog, never a path built by hand
```
SELECT * FROM read_json('…/v2026.09.10/catalog.json')
-- objects[] WHERE table = 'obs_env'
--   AND partition_value = 'oxygen_umol_kg_2'
```

library(calcofi4r)
con <- cc_get_db()                      # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("oxygen_umol_kg_2"))

Python

import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('oxygen_umol_kg_2')").df()

This page as data

JSONthis measurement's entry of the release record, verbatim
https://calcofi.io/measurements/oxygen_umol_kg_2.json

Read from measurements.json of release v2026.09.10, written at release by calcofi4db::build_measurements_catalog() beside taxa.json. The catalog's index is /measurements/; the JSON-LD on this page is a schema.org/DefinedTerm in the NERC P01 term set with a PropertyValue per series.

Cite

Cite the release; each dataset's own citation, licence and DOI are on its page — CTD Cast Files. The Explorer's Share → Cite writes it for the view you make.