Maximum buoyancy frequency N²
Maximum buoyancy frequency squared N2 (TEOS-10, 10 m running mean) between 10 and 200 m, at pycnocline_depth
1/s2key buoyancy_n2_maxno NERC concept says exactly thisseries buoyancy_n2_max
one value per cast One value per cast. This measurement is worked out once for each cast rather than read at every depth, so it has no depth profile and no anomaly against a normal; its values are rows of sample_measurement, not of obs_env.
CalCOFI holds 8,525 values of it from 8,525 sampling events in one dataset, 1993–2026, one per cast.R The largest N² of the cast, at the pycnocline: how sharp the main density step is, and so how strongly the surface layer is sealed off from the water below.C
- 8,525
- values
- 0
- flagged
- 1993–2026
- years
- 1
- dataset
- 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
buoyancy_n2_max· source columntemperature_ave; salinity_ave_corr; pressureone value per cast no flag at this grain no P01 concept
Explorerdb-queryThis page as JSON R · Python · Parquet
Every way in 6 ways · 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.
Explorerdb-querySELECT * FROM read_json('…/v2026.11.05/catalog.json')
-- objects[] WHERE table = 'sample_measurement'
-- then filter the rows:
-- measurement_type IN ('buoyancy_n2_max')library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "sample_measurement") |> filter(measurement_type %in% c("buoyancy_n2_max"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM sample_measurement WHERE measurement_type IN ('buoyancy_n2_max')").df()How it is measured no method registered yet
No method row is registered for this measurement yet (metadata/measurement_method.csv).
Why it matters 2 ways to say it · EOV Subsurface temperature
the GOOS specification sheet for this Essential Ocean Variable lists it
other ways to say why · 1
- Wikipedia In atmospheric dynamics, oceanography, asteroseismology and geophysics, the Brunt–Väisälä frequency, or buoyancy frequency, is a measure of the stability of a fluid to vertical displacements such as those caused by convection. More precisely it is the frequency at which a vertically displaced parcel will oscillate within a statically stable environment. Brunt–Väisälä frequency · CC BY-SA 4.0 · rev. 1381494343
Units and range 1/s2 · -0.2 … 0.2 declared · 0 flagged
1/s2
details
- bounds
- The registry declares
-0.2 … 0.2 1/s2forbuoyancy_n2_max; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Derived Products
buoyancy_n2_max1.16288e-05 · median 0.0003771 · 0.01581 1/s2 (5th–95th percentile 0.000205–0.0009765) - flags
- CTD Derived Products
buoyancy_n2_maxcarries no quality code at the release grain; qual_ok keeps all 8,525. - 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::ctd_pycnocline(): the value of buoyancy_n2 at pycnocline_depth (questions Q11)
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 month every month
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 Derived Products. The Explorer's Share → Cite writes it for the view you make.