{
  "key": "mld_temperature_02",
  "slug": "mld_temperature_02",
  "label": "Mixed-layer depth, temperature departure of 0.2 degC from 10 m (de Boyer Montegut et al. 2004)",
  "short_label": "Mixed-layer depth (ΔT 0.2 °C)",
  "description": "Mixed-layer depth, temperature departure of 0.2 degC from 10 m (de Boyer Montegut et al. 2004)",
  "units": "m",
  "units_nerc_p06": "http://vocab.nerc.ac.uk/collection/P06/current/ULAA/",
  "nerc_p01": null,
  "category": {
    "key": null,
    "name": "Physical Oceanography",
    "icon": "cat-physical",
    "realm": "env",
    "order": 1
  },
  "is_unified": false,
  "derivation": "calcofi4db::ctd_mld(criterion = 'temperature', threshold = 0.2, ref_depth = 10) on the 1 m bins; needs no salinity, so the only MLD on preliminary_without_bottle casts; an alternative to the headline mld_sigma_theta_002 (questions Q01)",
  "climatology": true,
  "bounds": {
    "valid_min": 0,
    "valid_max": 6500,
    "declared_by": [
      "mld_temperature_02"
    ]
  },
  "totals": {
    "n_values": 9605,
    "n_samples": 9605,
    "n_roots": 9605,
    "n_datasets": 1,
    "year_min": 1993,
    "year_max": 2026,
    "depth_min_m": null,
    "depth_max_m": null,
    "qual_ok_n": 9605,
    "n_flagged": 0
  },
  "series": [
    {
      "measurement_type": "mld_temperature_02",
      "dataset_key": "calcofi_ctd-derived",
      "source_column": "temperature_ave",
      "qual_column": null,
      "description": "Mixed-layer depth, temperature departure of 0.2 degC from 10 m (de Boyer Montegut et al. 2004)",
      "units": "m",
      "nerc_p01": null,
      "is_canonical": true,
      "n_values": 9605,
      "n_samples": 9605,
      "n_roots": 9605,
      "n_cells": 113,
      "n_cruises": 142,
      "year_min": 1993,
      "year_max": 2026,
      "depth_min_m": null,
      "depth_max_m": null,
      "years": {
        "1993": 130,
        "1994": 262,
        "1995": 259,
        "1996": 313,
        "1997": 281,
        "1998": 412,
        "1999": 261,
        "2000": 257,
        "2001": 250,
        "2002": 258,
        "2003": 312,
        "2004": 328,
        "2005": 280,
        "2006": 317,
        "2007": 283,
        "2008": 283,
        "2009": 311,
        "2010": 296,
        "2011": 310,
        "2012": 270,
        "2013": 320,
        "2014": 243,
        "2015": 299,
        "2016": 334,
        "2017": 319,
        "2018": 290,
        "2019": 231,
        "2020": 232,
        "2021": 256,
        "2022": 216,
        "2023": 309,
        "2024": 265,
        "2025": 324,
        "2026": 294
      },
      "months": [
        1753,
        591,
        376,
        2088,
        114,
        122,
        1602,
        673,
        117,
        956,
        1188,
        25
      ],
      "depth_bands": {
        "0-10": 0,
        "10-50": 0,
        "50-100": 0,
        "100-200": 0,
        "200-500": 0,
        "500-1000": 0,
        "1000-2000": 0,
        "2000+": 0
      },
      "qual": {
        "none": 9605
      },
      "qual_ok_n": 9605,
      "n_flagged": 0,
      "observed": {
        "min": 10.0558885582149,
        "p05": 10.6593696684299,
        "p50": 24.721577726218,
        "p95": 68.0731151032329,
        "max": 133.411473788328
      },
      "out_of_bounds": {
        "n": 0,
        "min": null,
        "max": null
      },
      "flags": [
        "no_flag_at_grain",
        "no_p01"
      ],
      "grain": "sample"
    }
  ],
  "related": [],
  "flags": [
    "no_label"
  ],
  "face": {
    "kind": "scale",
    "face_of": null,
    "stands_in_note": null,
    "source": "no NERC P01 on this key; shows its own familiar-scale figure only (D3)"
  },
  "method": [
    {
      "dataset_key": "calcofi_ctd-derived",
      "measurement_type": "mld_temperature_02",
      "platform": "ctd",
      "instrument": "Computed from the CTD profile (1 m bins)",
      "nerc_l22": null,
      "principle": "The mixed-layer depth: the shallowest depth where temperature departs from its value at the 10 m reference by 0.2 degC (de Boyer Montegut et al. 2004) on the 1 m bins; absent where the cast never crosses or does not reach 10 m. The only mixed-layer depth on preliminary_without_bottle casts.",
      "steps": [
        "take temperature at 10 m",
        "find the first depth 0.2 degC different"
      ],
      "wavelength_nm": null,
      "precision": null,
      "bibkeys": [
        "deboyermontegut2004"
      ],
      "calcofi_org_url": null,
      "text_fragment": null,
      "source": "the record's own derivation (measurement_type.csv)",
      "source_url": null
    }
  ],
  "why": [
    {
      "rank": 1,
      "kind": "authored",
      "text": "The mixed layer is the wind-stirred skin of the ocean above the density step that keeps deeper water from rising into it; how deep it is decides how much light the plankton in it get and whether deep nutrients can reach them, and off California warmer, more layered years have gone with fewer zooplankton.",
      "bibkeys": [
        "roemmich1995"
      ],
      "source_url": null,
      "eov": null,
      "goos_doc": null
    },
    {
      "rank": 2,
      "kind": "authored",
      "text": "There is no single mixed-layer depth: each criterion draws the line at a different density or temperature step from a 10 m reference, so the depths published here differ by design; compare a depth only with one made by the same criterion.",
      "bibkeys": [],
      "source_url": null,
      "eov": null,
      "goos_doc": null
    },
    {
      "rank": 3,
      "kind": "wikipedia",
      "text": "Mixed layer",
      "bibkeys": [],
      "source_url": "https://en.wikipedia.org/wiki/Mixed_layer",
      "eov": null,
      "goos_doc": null
    },
    {
      "rank": 4,
      "kind": "wikipedia",
      "text": "Pycnocline",
      "bibkeys": [],
      "source_url": "https://en.wikipedia.org/wiki/Pycnocline",
      "eov": null,
      "goos_doc": null
    }
  ],
  "grain": "sample"
}