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Slot: Day-Boundary Convention (day_boundary_convention)

Where the 24-hour day window starts. Mandatory. Daymet = local_midnight; PRISM = 24h_ending_1200_GMT; NARR / ERA5 sub-daily = utc_midnight. The single most-omitted slot in the literature and a known source of cross-study disagreement.

Tier: core

Why this slot matters

The single most-omitted slot in the environmental-health literature and a known source of cross-study disagreement: Daymet's local-midnight day and PRISM's 24h-ending-1200-GMT day slice the same thermometer readings differently, so the "daily Tmax" for the same calendar date can differ between products and lagged analyses can shift by a whole day. It is also the exposure-side half of the day-boundary cross-check against the clinical-side clinical_date_assignment_convention.

In plain terms

When does "Tuesday" start and end for this dataset — midnight local time, midnight in London, or noon-to-noon? Different products genuinely disagree, which changes which hot afternoon lands on which day.

URI: envar:slot/day_boundary_convention

Applicable Classes

Name Description Modifies Slot
TemporalReference Temporal provenance of an environmental exposure value: native temporal grain... yes

Properties

Type and Range

Property Value
Range DayBoundaryConventionEnum
Domain Of TemporalReference

Cardinality and Requirements

Property Value

Examples

Value
local_midnight
not_applicable

See Also

Identifier and Mapping Information

Annotations

property value
tier core
justification The single most-omitted slot in the environmental-health literature and a known source of cross-study disagreement: Daymet's local-midnight day and PRISM's 24h-ending-1200-GMT day slice the same thermometer readings differently, so the "daily Tmax" for the same calendar date can differ between products and lagged analyses can shift by a whole day. It is also the exposure-side half of the day-boundary cross-check against the clinical-side clinical_date_assignment_convention.
explanation When does "Tuesday" start and end for this dataset — midnight local time, midnight in London, or noon-to-noon? Different products genuinely disagree, which changes which hot afternoon lands on which day.
covered_by None

Schema Source

Mappings

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

LinkML Source

name: day_boundary_convention
annotations:
  tier:
    tag: tier
    value: core
  justification:
    tag: justification
    value: 'The single most-omitted slot in the environmental-health literature and
      a known source of cross-study disagreement: Daymet''s local-midnight day and
      PRISM''s 24h-ending-1200-GMT day slice the same thermometer readings differently,
      so the "daily Tmax" for the same calendar date can differ between products and
      lagged analyses can shift by a whole day. It is also the exposure-side half
      of the day-boundary cross-check against the clinical-side `clinical_date_assignment_convention`.'
  explanation:
    tag: explanation
    value: When does "Tuesday" start and end for this dataset — midnight local time,
      midnight in London, or noon-to-noon? Different products genuinely disagree,
      which changes which hot afternoon lands on which day.
  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 day-boundary slot anywhere in gaiaCatalog or gaia-db.
      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 records no day-boundary convention.
      amadeus:
        tag: amadeus
        annotations:
          extent:
            tag: extent
            value: absent
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: The NetCDF time axis (days since 1900-01-01) has no calendar day-edge
              clarification — pure ambiguity.
      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 field for where the 24-hour day window starts.
      codata:
        tag: codata
        annotations:
          extent:
            tag: extent
            value: absent
          status:
            tag: status
            value: asserted
          where:
            tag: where
            value: no column
          note:
            tag: note
            value: Day-boundary convention is an EnVar-novel commensurability slot
              no standard carries; not merely out-of-layer — genuinely absent.
description: Where the 24-hour day window starts. **Mandatory.** Daymet = `local_midnight`;
  PRISM = `24h_ending_1200_GMT`; NARR / ERA5 sub-daily = `utc_midnight`. The single
  most-omitted slot in the literature and a known source of cross-study disagreement.
title: Day-Boundary Convention
examples:
- value: local_midnight
  description: Daymet convention — day starts at local midnight.
- value: not_applicable
  description: Annual PM2.5 aggregate — no day boundary is meaningful.
from_schema: https://w3id.org/linkml/microschemas/envar
see_also:
- https://daymet.ornl.gov/
- https://prism.oregonstate.edu/
- https://psl.noaa.gov/data/gridded/data.narr.html
rank: 1000
domain_of:
- TemporalReference
range: DayBoundaryConventionEnum