Measurement · Physical Oceanography · 1/m

Beam attenuation coefficient

The registry carries no authored label for this measurement, so the name above is the canonical series' own description in metadata/measurement_type.csv (variable.csv holds the authored labels, five today).

NERC P01 ATTNXXZZP06 units UPRM 1/mkey beam_attenuation series beam_attenuation

600,762
values: 8,360
sampling events: 1993–2026
years: 1
dataset: 1–3,630 m
depth: Jan · Feb · Mar · Apr · May · Jun · Jul · Aug · Sep · Oct · Nov
seasons

Heads-up The beam_attenuation series from CTD Cast Files carries no flag at this grain, so its values cannot be screened this way.

Measured in

CTD Cast Files 600,762 values · 8,360 sampling events · 1993–2026 · 1–3,630 m · 96 grid cells · 119 cruises

series beam_attenuation · source column bat no bound declared no flag at this grain

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.

By depth

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

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

Range & quality

bounds: No physical bound is declared for this series in metadata/measurement_type.csv, so nothing is enforced at the ingest and the range below is simply what the release carries.
observed: CTD Cast Files beam_attenuation -12.29 · median 0.5875 · 75.64 1/m (5th–95th percentile 0.2817–13.82)
flags: CTD Cast Files beam_attenuation carries no quality code at the release grain; qual_ok keeps all 600,762.
baseline: A monthly climatology exists for this measurement (the release's climatology table: 1993–2013, dataset × grid cell × calendar month × 10 m bin), so the Explorer can draw anomalies against it rather than values.

Ways in

Explorermaps, sections and time series of this measurement — opens prefilled
https://calcofi.io/explore/?var=beam_attenuation
Explorer · a depth section vs normalthe newest cruise's section against the climatology baseline
https://calcofi.io/explore/?lens=section&var=beam_attenuation&anom=1
db-querySQL in your browser — the shell opens with this query
https://calcofi.io/db-query/?sql=SELECT+%2A+FROM+__TBL%3Aobs_env__+WHERE+measurement_type+%3D+%27beam_attenuation%27+LIMIT+100%3B
ERDDAP · CTD Cast FilesCalCOFI's own server, the CTD Cast Files table constrained to this series
https://erddap.calcofi.io/erddap/tabledap/calcofi_ctd-cast.html?&measurement_type=%22beam_attenuation%22
Parquetobs_env is partitioned by measurement_type in the content-addressed store — resolved through the release catalog, never a path built by hand
```
SELECT * FROM read_json('…/v2026.09.10/catalog.json')
-- objects[] WHERE table = 'obs_env'
--   AND partition_value = 'beam_attenuation'
```

library(calcofi4r)
con <- cc_get_db()                      # the promoted release
tbl(con, "obs_env") |> filter(measurement_type %in% c("beam_attenuation"))

Python

import calcofi4py as cc
con = cc.cc_get_db()
con.sql("SELECT * FROM obs_env WHERE measurement_type IN ('beam_attenuation')").df()

This page as data

JSONthis measurement's entry of the release record, verbatim
https://calcofi.io/measurements/beam_attenuation.json

Read from measurements.json of release v2026.09.10, 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.

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.