Surface PAR (CTD cast)
Surface PAR
µE/m²/skey sparP06 units UMESseries spar
CalCOFI holds 501,471 values of it from 7,098 sampling events in one dataset, 1993–2026, from the surface to 3,630 m. At 200–500 m it has risen 60.44 per decade since 1993.R Light is the other half of photosynthesis: how deep it reaches sets the bottom of the layer where anything can grow, and the water’s own plankton is what dims it.C
- 501,471
- values
- 18
- flagged
i
18 of these 501,471 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
spar· source columnspar· flag columnsparqno P01 concept 18 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 = 'spar'library(calcofi4r)
con <- cc_get_db() # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("spar"))import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('spar')").df()How it is measured CTD sensor
Why it matters 4 ways to say it
other ways to say why · 3
- Surface light and light at depth are measured together so a cast can be read as a fraction of that day’s sun rather than an absolute. needs a citation before it can be the pick
- Wikipedia Photic zone source
- Wikipedia Photosynthetically active radiation (PAR) designates the spectral range of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. Photosynthetically active radiation · CC BY-SA 4.0 · rev. 1372897979
The record’s own history 7 depth bands against the 1993–2013 normal
Each year against the normal i
Deeper than the climatology reaches: 3,084 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: 3,084 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 µE/m²/s · -100 … 5000 declared · 18 flagged
µE/m²/s (uE/m2/s in metadata/measurement_type.csv) · P06 units UMES
details
- bounds
- The registry declares
-100 … 5000 µE/m²/sforspar; a value outside it is dropped at the ingest (drop_out_of_bounds()). - observed
- CTD Cast Files
spar-83.36 · median 1.974 · 4998 µE/m²/s (5th–95th percentile 0–2085) - flags
- CTD Cast Files
sparsparqon 420 of 501,471 rows:0402 ·818; qual_ok keeps 501,453. 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.