Pressure
dbarkey pressureNERC P01 PRESPR01P06 units UPDBseries pressure
CalCOFI holds 704,112 values of it from 9,872 sampling events in one dataset, 1993–2026, from the surface to 3,630 m. At 200–500 m it has fallen 0.22 per decade since 1993.R Pressure is how a CTD knows where it is, and depth is where the story is: off Southern California oxygen, nitrate and phosphate have changed at different rates in each layer.C
- 704,112
- values
- 18
- flagged
i
18 of these 704,112 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). - 1993–2026
- years
- 1
- dataset
- 1–3,630 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
pressure· source columnpressure· flag columnpr_q18 flagged
Explorera depth section vs normaldb-queryERDDAPThis page as JSON R · Python · Parquet
Every way in 8 ways · ERDDAP · Parquet · R · Python · JSON
Read from measurements.json of release v2026.11.05, 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('…/v2026.11.05/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'pressure'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("pressure"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('pressure')").df()How it is measured Sea-Bird CTD profiling pressure sensor
A strain-gauge pressure sensor on the CTD, corrected to read zero at sea level. (calcofi.org CTD FAQ circa 2020)
CTD FAQ circa 2020 on calcofi.org ↗Why it matters 3 ways to say it
other ways to say why · 2
- Every profile in the record is placed in the water column by its pressure, so a depth error moves a value into the wrong layer rather than losing it. needs a citation before it can be the pick
- Wikipedia Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the ambient pressure. Pressure · CC BY-SA 4.0 · rev. 1378601778
The record’s own history 7 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 3,237 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: 3,237 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 dbar · 0 … 6500 declared · 18 flagged
dbar · P06 units UPDB
details
- bounds
- The registry declares
0 … 6500 dbarforpressure; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Cast Files
pressure1.005 · median 185.4 · 3688 dbar (5th–95th percentile 16.11–514.2) - flags
- CTD Cast Files
pressurepr_qon 420 of 704,112 rows:0402 ·818; qual_ok keeps 704,094. 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 × station × the cruise's month × 10 m bin), so the Explorer can draw anomalies against it rather than values.
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 1–3,630 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, v2026.11.05
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.