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sea level

vr.tr.sea-level · thing-q125465

Let an agent explain sea level and how it is defined and measured, relay tidal, eustatic and past sea level concepts from geodesy, oceanography and geology references, describe sea level rise with findings attributed, and distinguish mean sea level from tide level, geoid and local datums.

Thing Registry Cross-cutting context XCT.QLT
Bundle → Layer → Finding → QuestionsClassifiersWhat it isWhy it existsDistinguishing featuresWhat robots and AI may and may not doMoral aspectsOwnersLinks to other meta-modelsIdentity and identifiersDirect propertiesRecognitionCapabilities and actionsHazards and failure modesStandards and interfacesContext of useSources

Bundle → Layer → Finding → Questions Filled

4 bundles · 8 layers · 8 findings · 16 questions

Understand What sea level is.

Definition

Definition.

Definition

Definition.

  1. What is sea level, and how do mean sea level, tide level, eustatic sea level and the geoid differ? definition
  2. Is the question about the datum, tides, geology or climate change? boundary

Measurement

Measurement.

Measurement

Measurement.

  1. How is sea level measured by tide gauges and satellite altimetry? measurement
  2. Which entry fits tide gauge? action
Change Sea level change.

Rise

Current rise.

Rise

Rise.

  1. How fast is global sea level rising, why, and what are projections, as assessments report? provenance
  2. Which references are standard? provenance

Past

Past sea level.

Past

Past.

  1. How has sea level changed over geological time, and how is past sea level reconstructed? provenance
  2. Which sources are cited? provenance
Use Use as a datum.

Datums

Datums.

Datums

Datums.

  1. How do national datums and chart datums relate to mean sea level? provenance
  2. Which entry fits vertical datum? action

Mapping

Mapping and navigation.

Mapping

Mapping.

  1. How are elevations and depths referenced to sea level in maps and charts? provenance
  2. Which entry fits nautical chart? action
Context Impacts and adaptation.

Impacts

Impacts.

Impacts

Impacts.

  1. How does sea level rise affect coasts, cities and islands, with findings attributed? provenance
  2. Is the presentation neutral? boundary

Adaptation

Adaptation.

Adaptation

Adaptation.

  1. How do communities adapt to rising seas? provenance
  2. Which entry fits coastal management? action

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.QLT
Other names and narrower kinds
tide level, Past sea level, Eustatic sea level

What it is Filled

The average level of the ocean surface, used as a vertical datum for measuring elevation and depth, defined locally by tide gauges as mean sea level over a period and globally by satellite altimetry, varying with tides as tide level, with eustatic changes in the volume of the oceans over geological time, and reconstructed as past sea level from geological records; global mean sea level is rising as ice melts and oceans warm.

Why it exists Filled

Let an agent explain sea level and how it is defined and measured, relay tidal, eustatic and past sea level concepts from geodesy, oceanography and geology references, describe sea level rise with findings attributed, and distinguish mean sea level from tide level, geoid and local datums.

Distinguishing features Filled

  • Vertical datum
  • Tidal and long-term variation
  • Global and local
  • Climate indicator

What robots and AI may and may not do Filled

Must not

  • Present local sea level change without accounting for land subsidence or uplift.
  • Mix up vertical datums when reporting heights or depths.
  • Present a partisan view of sea level rise as settled or deny measured trends.
  • Alter or fabricate tide gauge or satellite records.

Only with a human decision

  • Using sea level projections for flood defence or planning decisions.

May

  • Report sea level measurements with the datum, method and period used.
  • Distinguish local relative sea level from the global mean.

Moral aspects Filled

  • Coastal and island communities face loss of homes and land from rising seas.
  • Datum errors in charts and plans can endanger ships and buildings.

Who is affected

  • Coastal residents
  • Island nations
  • Mariners

Owners Filled

Steward

National mapping and hydrographic agencies maintain datums and tide gauges.

Master systems

  • Tide gauge and sea level data archives

Links to other meta-models Filled

parent

  • Q135524331 - registry parent class
  • Q1929501 - registry parent class
  • Q9364781 - registry parent class

related

  • vertical datum - in registry terms
  • water level - in registry terms
  • two-dimensional continuant fiat boundary - in registry terms
  • geoid - a gravitational equipotential surface

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.sea-level
  • Wikidata: Q125465 (https://www.wikidata.org/wiki/Q125465)

Direct properties not applicable Not applicable

  • global mean rise since 1900: about 20 cm
  • current rate: about 4 mm per year - satellite era
  • Last Glacial Maximum sea level: about 120-130 m lower note

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Average level of the ocean surface
  • Mean sea level, tide level, eustatic sea level, past sea level
  • The geoid is a gravitational surface; local datums differ; tide level varies hourly
  • Not a visible object; the ocean surface as a reference.

Capabilities and actions required Filled

  • explain definitions
  • relay measurement
  • describe sea level change
  • distinguish related concepts

Hazards and failure modes required Filled

  • Confusing local and global sea level
  • Ignoring land subsidence in relative sea level
  • Partisan framing of sea level rise

Standards and interfaces required Filled

  • National vertical datum standards
  • IPCC assessments of sea level change
  • IHO tidal datum conventions

Context of use required Filled

  • Reference for elevation and monitoring ocean change.
  • mean sea level at tide gauges
  • tide level and tidal datums
  • global mean sea level from altimetry
  • eustatic sea level
  • relative sea level including land movement
  • past sea level from geological records

Sources Filled

  1. Wikidata item Q125465: sea level - identity and sense of the item
  2. Wikipedia: Sea level - general description of the item

Open questions

  • Should sea level rise and tidal datum be separate primary entries?
  • How should geodesy and climate sources be linked?
  • The registry entry has merged aliases naming distinct concepts; should they be split off?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q125465/spec.json