Fluorescence voltage
- 688,917
- values
- 221
- flagged
i
221 of these 688,917 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). - 9,675
- sampling events
- 1993–2026
- years
- 1
- dataset
- 1–3,630 m
- depth
- Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov
- seasons
stands in: chlorophyll-a measured fluorometrically’s face, raw CTD fluorometer voltage
No definition of its own: the estimate is described by its derivation, under How.
Is the biomass of the ocean changing?
CalCOFI holds 688,917 values of it from 9,675 sampling events in one dataset, 1993–2026, from the surface to 3,630 m. At 200–500 m it has fallen 0.17 per decade since 1993.R Every phytoplankter carries chlorophyll-a, so it is the standard measure of how much plant life the sunlit layer holds: the base of the food web the rest of the survey counts.C
other ways to say why · 5
- The fluorometer reads a profile continuously where the bottles read a handful of depths, so it is what shows the shape of the chlorophyll maximum. needs a citation before it can be the pick
- Chlorophyll is what satellites see as ocean colour, and bottle chlorophyll like CalCOFI’s is among the ground truth their algorithms were fitted to. needs a citation before it can be the pick
- GOOS asks Is the biomass of the ocean changing? source
- Wikipedia Phytoplankton source
- Wikipedia Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. Chlorophyll a · CC BY-SA 4.0 · rev. 1373717553
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.
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
fluorescence_v· source columnfluor_v· flag columnfluor_qno P01 concept 221 flagged
The structure
RDKit 2026.03.6 from the ChEBI molfile, in the page’s ink · CC BY 4.0. ChEBI’s roles are never shown.
How it is measured
The CTD fluorometer's raw voltage, calibrated daily against a standard and a blocked-light zero; not itself chlorophyll units. (calcofi.org CTD FAQ circa 2020)
CTD FAQ circa 2020 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.
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
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.
the GOOS specification sheet for this Essential Ocean Variable lists it, and asks
GOOS asks
- Is the biomass of the ocean changing?
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.
ExplorerExplorer · a depth section vs normaldb-queryi
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.
SELECT * FROM read_json('…/v2026.10.14/catalog.json')
-- objects[] WHERE table = 'obs_env'
-- AND partition_value = 'fluorescence_v'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("fluorescence_v"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('fluorescence_v')").df()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.
Range & quality
details
- bounds
- The registry declares
-1 … 15 Vforfluorescence_v; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Cast Files
fluorescence_v-0.1229 · median 0.036 · 10.06 V (5th–95th percentile 0.0037–0.9532) - flags
- CTD Cast Files
fluorescence_vfluor_qon 221 of 688,917 rows:8140 ·981; qual_ok keeps 688,696. 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.
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.