Potential density (TEOS-10)
Potential density anomaly (sigma-theta, TEOS-10) per bottle, from the bottle's own temperature and salinity
kg/m³key sigma_theta_teos10NERC P01 SIGTPR03P06 units UKMCseries sigma_theta_teos10
CalCOFI holds 841,673 values of it from 34,790 sampling events in one dataset, 1949–2021, from the surface to 5,351 m. At 10–50 m it has fallen 0.02 per decade since 1984.R
- 841,673
- values
- 0
- flagged
- 1949–2021
- years
- 1
- dataset
- 0–5,351 m
- depth
- every month
- months
Measured in
1 dataset
i
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.
i
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.
-
series
sigma_theta_teos10· source columntemperature; salinity; depthno flag at this grain
Explorera depth section vs normaldb-queryThis page as JSON R · Python · Parquet
Every way in 7 ways · Parquet · R · Python · JSON
Read from measurements.json of release v2026.10.21, 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.
ExplorerExplorer · a depth section vs normaldb-querySELECT * FROM read_json('…/v2026.10.21/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'sigma_theta_teos10'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("sigma_theta_teos10"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('sigma_theta_teos10')").df()How it is measured Computed from the bottle's own temperature and salinity (TEOS-10)
Potential density anomaly referenced to 0 dbar (sigma-theta) by TEOS-10, from each bottle's own temperature and salinity at the sea pressure of its depth; the modern value beside the bottle database's legacy DECODR sigma_theta. A bottle whose temperature or salinity the provider flags 8 or 9 has none. (the record's own derivation (measurement_type.csv; calcofi4db::bottle_spice_sigma0()))
- gsw_p_from_z
- gsw_SA_from_SP
- gsw_CT_from_t
- gsw_sigma0
Why it matters no reason registered yet
The record’s own history 7 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 3,962 values at 2000+ m have no
normal to depart from, because the release’s climatology stops at its
deepest built bin. Carrying it to the bottom is one argument of
build_climatology() and puts these bands on the page too.
i
Deeper than the climatology reaches: 3,962 values at 2000+ m have no
normal to depart from, because the release’s climatology stops at its
deepest built bin. Carrying it to the bottom is one argument of
build_climatology() and puts these bands on the page too.
Units and range kg/m³ · -8 … 37 declared · 0 flagged
kg/m³ (kg/m3 in metadata/measurement_type.csv) · P06 units UKMC
details
- bounds
- The registry declares
-8 … 37 kg/m³forsigma_theta_teos10; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- Bottle Derived Products
sigma_theta_teos1020.94 · median 25.99 · 28.15 kg/m³ (5th–95th percentile 24.12–27.2) - flags
- Bottle Derived Products
sigma_theta_teos10carries no quality code at the release grain; qual_ok keeps all 841,673. - baseline
- A monthly climatology exists for this measurement (the release's climatology table: 1993–2013, dataset × station × the cruise's month × 10 m bin), so the Explorer can draw anomalies against it rather than values.
- derivation
- calcofi4db::bottle_spice_sigma0(): sea pressure gsw_p_from_z(-depth, latitude), then gsw_SA_from_SP, gsw_CT_from_t, gsw_sigma0 (TEOS-10, IOC/SCOR/IAPSO 2010) on the bottle's own temperature (T_degC) and salinity (Salnty); a bottle whose T_qual or S_qual is 8 or 9 has none. The bottle database's own sigma_theta is DECODR's legacy value, kept beside it
The familiar scale i
Bars are each series' 5th–95th percentile, the line its minimum to maximum, the ring its median;
the marks are metadata/measurement_scale.csv's, each hovering to its own source.
i
Bars are each series' 5th–95th percentile, the line its minimum to maximum, the ring its median;
the marks are metadata/measurement_scale.csv's, each hovering to its own source.
By depth · by month 0–5,351 m · every month
By depth i
Values per depth band at the release grain, one thin bar per series. The bands are the
record's own (0-10 … 2000+ m).
i
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 i
Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in
the months the ships sail.
i
Values per calendar month, one row per series: CalCOFI's quarterly cruises show as peaks in the months the ships sail.
Cite the release, v2026.10.21
Cite the release; each dataset's own citation, licence and DOI are on its page — Bottle Derived Products. The Explorer's Share → Cite writes it for the view you make.