CalCOFI.io CalCOFI.io open data ecosystem
Measurement · Carbonate System

Seawater pH

key sw_ph series sw_ph
2,473
values
0
flagged
2,473
sampling events
2016–2018
years
1
dataset
surface
depth
Aug · Oct · Nov
seasons
What

stands in: ph’s face, METS underway sensor

No definition of its own: the estimate is described by its derivation, under How.

How
underway, on the mast

not found on calcofi.org ↗
Why

What are rates and impacts of ocean acidification?

CalCOFI holds 2,473 values of it from 2,473 sampling events in one dataset, 2016–2018, at the surface.R Upwelling brings water that is naturally low in pH and carbonate onto the shelf; ocean acidification pushes it further toward water that is corrosive to shells.C

other ways to say why · 4
  • authored Lower pH means less carbonate in the water, and the shells of pteropods off California already show dissolution where corrosive water reaches the surface. needs a citation before it can be the pick
  • GOOS asks What are rates and impacts of ocean acidification? source
  • Wikipedia PH source
  • Wikipedia Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Ocean acidification · CC BY-SA 4.0 · rev. 1372947827

The measurement

Measured in
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.

  • Underway Meteorological (METS) 2,473 values · 2,473 sampling events · 2016–2018 · surface · 71 grid cells · 3 cruises
    series sw_ph · source column sw_ph no flag at this grain no P01 concept

How it is measured

Underway Meteorological (METS) · underway, on the mast
no flag at this grain
not found on calcofi.org ↗

Why it matters

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.

The record’s own history
i

The release builds no climatology for this measurement, so there is no normal to draw a departure from.

Essential Ocean Variable
Inorganic carbon

the GOOS specification sheet for this Essential Ocean Variable lists it, and asks

GOOS asks

  • What are rates and impacts of ocean acidification?

GOOS specification sheet ↗ · quoted, not copied

The record

Ways in
i

Read from measurements.json of release v2026.10.14, 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.

Explorerdb-query
ERDDAP · Underway Meteorological (METS)CalCOFI's own server, the Underway Meteorological (METS) table constrained to this series
https://erddap.calcofi.io/erddap/tabledap/calcofi_mets.html?&measurement_type=%22sw_ph%22

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).

By month
i

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

Range & quality

bounds6 … 9observed8.269 … 8.829flagged0baselineno climatology
details
bounds
The registry declares 6 … 9 for sw_ph; a value outside it is dropped at the ingest (drop_out_of_bounds()).
observed
Underway Meteorological (METS) sw_ph 8.269 · median 8.409 · 8.829 (5th–95th percentile 8.369–8.652)
flags
Underway Meteorological (METS) sw_ph carries no quality code at the release grain; qual_ok keeps all 2,473.
baseline
No climatology row is built for this measurement, so the Explorer draws values, not anomalies.

Cite

Cite the release; each dataset's own citation, licence and DOI are on its page — Underway Meteorological (METS). The Explorer's Share → Cite writes it for the view you make.