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Slot: Calendar (CF) (calendar)

Calendar of the time axis. gregorian is the default; only matters when a source uses a non-standard calendar. Covers both the CF calendar values and product-specific conventions that CF has no term for — e.g. Daymet's fixed 365-day year (daymet_365), which keeps Feb 29 but drops Dec 31 in leap years and is therefore neither gregorian nor noleap.

Tier: recommended

Why this slot matters

Some climate-model output uses non-standard calendars (365-day noleap, 360-day); joining such a series to real-world Gregorian clinical dates without converting shifts daily values progressively through the year — a silent, cumulative misalignment.

In plain terms

Most data uses the ordinary calendar, but some climate models simplify — for example pretending every year has exactly 365 days (no leap days) or twelve 30-day months. If you line those dates up against a real calendar without converting, they slowly drift out of sync.

URI: envar:slot/calendar

Applicable Classes

Name Description Modifies Slot
TemporalReference Temporal provenance of an environmental exposure value: native temporal grain... no

Properties

Type and Range

Property Value
Range CalendarEnum
Domain Of TemporalReference

Cardinality and Requirements

Property Value

Examples

Value
gregorian
daymet_365

See Also

Identifier and Mapping Information

Annotations

property value
tier recommended
justification Some climate-model output uses non-standard calendars (365-day noleap, 360-day); joining such a series to real-world Gregorian clinical dates without converting shifts daily values progressively through the year — a silent, cumulative misalignment.
explanation Most data uses the ordinary calendar, but some climate models simplify — for example pretending every year has exactly 365 days (no leap days) or twelve 30-day months. If you line those dates up against a real calendar without converting, they slowly drift out of sync.
covered_by None

Schema Source

Mappings

Mapping Type Mapped Value
self envar:calendar
native envar:calendar

LinkML Source

name: calendar
annotations:
  tier:
    tag: tier
    value: recommended
  justification:
    tag: justification
    value: Some climate-model output uses non-standard calendars (365-day noleap,
      360-day); joining such a series to real-world Gregorian clinical dates without
      converting shifts daily values progressively through the year — a silent, cumulative
      misalignment.
  explanation:
    tag: explanation
    value: Most data uses the ordinary calendar, but some climate models simplify
      — for example pretending every year has exactly 365 days (no leap days) or twelve
      30-day months. If you line those dates up against a real calendar without converting,
      they slowly drift out of sync.
  covered_by:
    tag: covered_by
    annotations:
      omop_gaia:
        tag: omop_gaia
        annotations:
          extent:
            tag: extent
            value: absent
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: No calendar/time-origin slot in gaia.
      degauss:
        tag: degauss
        annotations:
          extent:
            tag: extent
            value: absent
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: DeGAUSS emits no calendar field.
      amadeus:
        tag: amadeus
        annotations:
          extent:
            tag: extent
            value: full
          status:
            tag: status
            value: verified
          where:
            tag: where
            value: thredds_dataset.xml day axis (days since 1900-01-01, calendar =
              gregorian)
          evidence:
            tag: evidence
            value: EnVar/examples/heat/COMPARISON.md §H (time-origin / calendar ✅)
          note:
            tag: note
            value: The THREDDS day axis declares the calendar (gregorian) and time
              origin explicitly.
      cher:
        tag: cher
        annotations:
          extent:
            tag: extent
            value: absent
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: C-HER has no calendar-of-time-axis field.
      codata:
        tag: codata
        annotations:
          extent:
            tag: extent
            value: out_of_layer
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: The calendar of a specific product's time axis is instance-layer
              representation detail outside the conceptual EV/DDI-CDI layer.
description: Calendar of the time axis. `gregorian` is the default; only matters when
  a source uses a non-standard calendar. Covers both the CF `calendar` values and
  product-specific conventions that CF has no term for — e.g. Daymet's fixed 365-day
  year (`daymet_365`), which keeps Feb 29 but drops Dec 31 in leap years and is therefore
  neither `gregorian` nor `noleap`.
title: Calendar (CF)
examples:
- value: gregorian
  description: The default; used by ACAG PM2.5.
- value: daymet_365
  description: Daymet — fixed 365-day year; keeps Feb 29, drops Dec 31 in leap years.
from_schema: https://w3id.org/linkml/microschemas/envar
see_also:
- https://cfconventions.org/cf-conventions/cf-conventions.html#calendar
rank: 1000
domain_of:
- TemporalReference
range: CalendarEnum