https://calcofi.io/datasets/calcofi_ctd-derived/ CTD Derived Products California Cooperative Oceanic Fisheries Investigations 2026-10-21 eng Hydrographic products DERIVED from the CalCOFI CTD cast profiles rather than measured: spice (spiciness at 0 dbar, TEOS-10) and the sensor-pair averaged sigma-theta at every published CTD depth; and, per cast, the mixed-layer depth (the CalCOFI legacy definition, with two alternative criteria beside it), the depth and value of the chlorophyll-a maximum and the chlorophyll-a integrated over the top 200 m, by the definitions of the CalCOFI CTD team. Computed from the full-resolution 1 m bins of the CalCOFI CTD Cast Files after the provider's quality flags are applied. EARTH SCIENCE > OCEANS > SALINITY/DENSITY > DENSITY EARTH SCIENCE > OCEANS > OCEAN CIRCULATION > OCEAN MIXED LAYER EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > CHLOROPHYLL GCMD Science Keywords Physical Oceanography sigma_theta_ave kg/m3 spiciness0 https://calcofi.io/datasets/calcofi_ctd-derived/ 29.8–37.8°N, 126.5–117.3°W -126.4843 -117.2734 37.8491 29.8268 1993 2026 CalCOFI data@calcofi.io Input. The full-resolution 1 m bins of the CalCOFI CTD Cast Files, as the calcofi_ctd-cast ingest stages them (obs_ctd_full), for the cast of each station occupation that the ingest publishes in obs (the down cast, the up cast only where no down cast exists). A value the provider flags 8 (questionable) or 9 (bad) is dropped before anything is computed; the temperature and salinity used are the sensor-pair averages the ctd-cast ingest rebuilds by the provider's flags (combine_sensor_pair_sql()). Tiers. final and preliminary_with_bottle casts get every product. preliminary_without_bottle casts have no bottle-corrected salinity, so they get only the temperature-criterion mixed-layer depth: nothing salinity-based (spice, sigma-theta, density MLD) and no chlorophyll estimate, following Rasmus Swalethorp's rule (2026-09-09) that uncorrected sensors are not shown. Spice (spiciness0, kg m-3): absolute salinity from practical salinity (gsw_SA_from_SP), conservative temperature from in-situ temperature (gsw_CT_from_t), then spiciness at 0 dbar (gsw_spiciness0), TEOS-10 via the Gibbs SeaWater toolbox (IOC, SCOR and IAPSO 2010; McDougall and Barker 2011) and McDougall and Krzysik (2015). Positive is spicy (warm, salty), negative minty. Averaged sigma-theta (sigma_theta_ave, kg m-3): the two sensors' sigma-theta combined by the provider's flags, the same rule as every CTD pair. Mixed-layer depth (m, per cast): the CalCOFI legacy definition given by the CTD team (Rasmus Swalethorp, 2026-09-23), the depth at which sigma-theta is 0.02 kg m-3 greater than at a reference depth of 10 m (mld_sigma_theta_002). Two alternative criteria are published beside it: a sigma-theta increase of 0.125 kg m-3 (Levitus 1982; mld_sigma_theta_0125) and a temperature departure of 0.2 deg C (de Boyer Montegut et al. 2004; mld_temperature_02, the only one a cast without bottle-corrected salinity can have). Each is interpolated linearly between the bracketing bins; a cast that never crosses the threshold, or does not reach 10 m, has none. The 0.03 kg m-3 criterion released in v2026.10.01 (mld_sigma_theta_003) is retired. Chlorophyll-a maximum (per cast): the depth of the highest value of a 3 m running mean of the bottle-fitted sensor estimate (est_chlorophyll_a_sta_corr), and that mean (Rasmus Swalethorp, 2026-09-23: a 3 m mean so a narrow spike is not the maximum while a narrow layer still is). At the top and bottom of the profile the mean is over the bins within reach. Integrated chlorophyll-a (mg m-2, per cast): the sum of the same estimate's 1 m bins over the top 200 m, or to the cast bottom if shallower (chl_integrated_depth says how deep it reached; Rasmus Swalethorp, 2026-09-23). A bin missing inside the profile is interpolated, and the shallowest bin is carried to the surface only when it is no deeper than 5 m. Relative geostrophic velocity between adjacent stations of each CalCOFI line, referenced to 500 dbar, is computed by the same ingest (ctd_geostrophic()) but is not in the release while the treatment of shelf pairs and closely spaced stations is reviewed with the CTD team (questions.csv Q03, Q04; CalCOFI/workflows#103). Every rule is a function in calcofi4db (ctd_spice(), ctd_sigma_theta_ave(), ctd_mld(), ctd_chl_max(), ctd_integrate(), ctd_geostrophic()) with unit tests. The mixed-layer and chlorophyll definitions are the CTD team's (questions.csv Q01, Q02). References. de Boyer Montegut, C., G. Madec, A. S. Fischer, A. Lazar and D. Iudicone (2004), Mixed layer depth over the global ocean: an examination of profile data and a profile-based climatology, J. Geophys. Res. 109, C12003, doi:10.1029/2004JC002378. Levitus, S. (1982), Climatological Atlas of the World Ocean, NOAA Professional Paper 13. McDougall, T. J. and O. A. Krzysik (2015), Spiciness, J. Mar. Res. 73, 141-152, doi:10.1357/002224015816665589. IOC, SCOR and IAPSO (2010), The international thermodynamic equation of seawater - 2010 (TEOS-10), IOC Manuals and Guides 56. McDougall, T. J. and P. M. Barker (2011), Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox, SCOR/IAPSO WG127. Kelley, D., C. Richards and WG127 (2023), gsw: Gibbs Sea Water Functions, R package. obs The occurrence-headline long table: one scalar measurement per row, environmental (realm = 'env') and biological (realm = 'bio') together. Biological taxon is the global taxon_key; sub-occurrence detail (length/stage bins, behavior) lives in obs_attribute, and event-level effort in sample_measurement. data_0.parquet 19732825 d5487fea8586390ad71d1958808b3c76ea684db0bcd3a0a9aac7b518a033a0d4 Apache Parquet https://storage.googleapis.com/calcofi-db/ducklake/tables/obs/dataset_key=calcofi_ctd-derived/039a0f3d598825ccbcd9aaee/data_0.parquet obs_id Observation ID Surrogate key, renumbered globally when the release concatenates the per-dataset shards. BIGINT dimensionless integer realm Realm env for physical/chemical measurements, bio for organism observations. VARCHAR env for physical/chemical measurements, bio for organism observations. dataset_key Dataset Key Provenance stamp: provider_dataset. VARCHAR Provenance stamp: provider_dataset. sample_key Sample Key The sampling event this observation came from; joins sample. VARCHAR The sampling event this observation came from; joins sample. grid_key Grid Key CalCOFI station grid cell, denormalized from sample so rollups need no join. NULL for region-pooled data. VARCHAR CalCOFI station grid cell, denormalized from sample so rollups need no join. NULL for region-pooled data. cruise_key Cruise Key Cruise, denormalized from sample so rollups need no join. VARCHAR Cruise, denormalized from sample so rollups need no join. latitude Latitude Observation latitude (WGS84). DOUBLE degree real longitude Longitude Observation longitude (WGS84). DOUBLE degree real datetime Datetime Observation time (UTC). NULL for region-pooled data with no event time. TIMESTAMP YYYY-MM-DDThh:mm:ss depth_min_m Depth Min Shallowest depth this observation represents. DOUBLE meter real depth_max_m Depth Max Deepest depth this observation represents; equal to depth_min_m for point measurements (bottle, CTD scan). DOUBLE meter real taxon_key Taxon Key Global taxon key, worms:<AphiaID> or itis:<TSN> for birds. NULL for env rows. Joins taxon. VARCHAR Global taxon key, worms:<AphiaID> or itis:<TSN> for birds. NULL for env rows. Joins taxon. life_stage Life Stage Life stage where the source resolves one (larva, adult, juvenile, egg, phyllosoma). VARCHAR Life stage where the source resolves one (larva, adult, juvenile, egg, phyllosoma). measurement_type Measurement Type Measured quantity; joins the measurement_type vocabulary. VARCHAR Measured quantity; joins the measurement_type vocabulary. measurement_value Measurement Value The measured value, in the units measurement_type declares. DOUBLE dimensionless real measurement_qual Measurement Qualifier Source quality flag, verbatim. VARCHAR Source quality flag, verbatim. measurement_prec Measurement Precision Source-reported precision where available. DOUBLE dimensionless real hex_id Hex ID H3 cell at resolution 10, stored as UBIGINT. Aggregate coarser at query time with h3_cell_to_parent(hex_id, res) — there is no per-resolution column ladder. UBIGINT dimensionless whole sample_measurement Event-level (effort) measurements: quantities that describe the sampling event itself rather than anything observed in it — net volume filtered, standard haul factor, proportion sorted, bottle cast conditions. Kept apart from obs so effort is never mistaken for an observation. sample_measurement_id Sample Measurement ID Surrogate key. BIGINT dimensionless integer sample_key Sample Key The sampling event this effort measurement describes; joins sample. VARCHAR The sampling event this effort measurement describes; joins sample. dataset_key Dataset Key Provenance stamp: provider_dataset. VARCHAR Provenance stamp: provider_dataset. measurement_type Measurement Type Measured quantity; joins the measurement_type vocabulary. VARCHAR Measured quantity; joins the measurement_type vocabulary. measurement_value Measurement Value The measured value, in the units measurement_type declares. DOUBLE dimensionless real measurement_qual Measurement Qualifier Source quality flag, verbatim. VARCHAR Source quality flag, verbatim. measurement_type measurement_type Measurement Type Measurement Type VARCHAR Measurement Type description Description Description VARCHAR Description units Units Units VARCHAR Units valid_min Valid Min Valid Min DOUBLE dimensionless real valid_max Valid Max Valid Max DOUBLE dimensionless real valid_depth_min_m Valid Depth Min M Valid Depth Min M DOUBLE dimensionless real valid_depth_max_m Valid Depth Max M Valid Depth Max M DOUBLE dimensionless real derivation Derivation Derivation VARCHAR Derivation is_canonical Is Canonical Is Canonical BOOLEAN Is Canonical _source_column Source Column Source Column VARCHAR Source Column _source_table Source Table Source Table VARCHAR Source Table _source_datasets Source Datasets Source Datasets VARCHAR Source Datasets _qual_column Qual Column Qual Column VARCHAR Qual Column _prec_column Prec Column Prec Column VARCHAR Prec Column grain Grain Grain VARCHAR Grain denominator Denominator Denominator VARCHAR Denominator category Category Category VARCHAR Category variable Variable Variable VARCHAR Variable nerc_p01 Nerc P01 Nerc P01 VARCHAR Nerc P01 units_nerc_p06 Units Nerc P06 Units Nerc P06 VARCHAR Units Nerc P06 provider Provider Provider VARCHAR Provider dataset Dataset Dataset VARCHAR Dataset CalCOFI. (2026). CalCOFI CTD Derived Hydrographic Products (from the CalCOFI CTD Cast Files). CalCOFI.io. https://calcofi.io/workflows/ingest_calcofi_ctd-derived.html calcofi_ctd-derived https://calcofi.io/datasets/calcofi_ctd-derived/ v2026.10.21 CalCOFI (2026). CalCOFI Integrated Database, release v2026.10.21 [Data set]. Scripps Institution of Oceanography, NOAA Fisheries, and California Department of Fish and Wildlife. https://calcofi.io/db-schema/?v=v2026.10.21 2026-10-21