salinity
Enable an agent to recognise, compare and interpret salinity observations and determine which further measurements or responses their evidence supports.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to recognise, compare and interpret salinity observations and determine which further measurements or responses their evidence supports.
Salinity is the salt content of water or another medium, expressed through a specified compositional measure or an operational scale, with seawater, freshwater and soil applications using different conventions.
It can be Identify the salinity convention and reject ambiguous unit labels pending clarification; Compare observations after checking medium, method, scale and sampling compatibility; Derive a salinity estimate using a documented conversion within its validated domain; Detect supported salinity gradients, trends and use-specific threshold crossings; Request composition analysis, calibration checks or additional sampling when interpretation is underdetermined; Evaluate whether salinity evidence supports a proposed response and refer intervention design to the relevant process model.
Distinguishing features
An instance describes a medium's salt-related quality; a salt specimen or a dissolved salt mass without a reference amount does not by itself specify salinity.
A reported number must identify its convention: Practical Salinity and Absolute Salinity represent different operational quantities. [TEOS-10](https://teos-10.org/index.htm)
An electrical conductivity reading requires a declared interpretation before it functions as a salinity estimate; soil saturation-extract conductivity is an established soil salinity indicator. [FAO](https://www.fao.org/4/t0667e/t0667e05.htm)
A sodium hazard or individual-ion concentration must remain distinguishable from overall salinity. [FAO](https://www.fao.org/4/t0667e/t0667e05.htm)
A label such as saline or brackish must identify the classification scheme and medium before it can support a decision.
Scope
+ Definitions and operational conventions used to express salinity
+ Salinity observations tied to a sample, medium, location and time
+ Measurement methods, calibration, uncertainty and conversion assumptions
+ Spatial gradients and temporal changes in salinity
+ Application-specific salinity classifications and decision criteria
- Chemical identities and complete composition models of individual salts
- Water bodies, soils and industrial solutions as independently modelled things
- Conductivity meters and other measurement devices as equipment
- Sodicity, specific-ion toxicity, hardness and alkalinity as distinct qualities
- Salinisation processes and desalination systems as independently modelled processes
- Sensory saltiness and dietary sodium exposure
Characteristics
- Salinity-bearing medium
- Referenced water sample, aqueous solution, soil pore water or prepared soil extract Establishes what bears the quality and prevents an extract measurement from silently becoming an in-situ water measurement.
- Operational convention
- Practical Salinity; Absolute Salinity; declared salt mass fraction or concentration; soil extract conductivity indicator; other explicitly defined convention Determines what the reported value means and whether comparison or conversion is justified.
- Reported value and basis
- Numeric value with declared scale and denominator; examples include dimensionless Practical Salinity, Absolute Salinity in g/kg and soil extract conductivity in dS/m Preserves distinctions among a salinity scale, a mass fraction and an operational proxy. [TEOS-10](https://teos-10.org/index.htm), [FAO](https://www.fao.org/4/t0667e/t0667e05.htm)
- Measurement conditions
- Temperature in °C, pressure with stated reference and unit, and soil extraction ratio or moisture condition where applicable Makes the observation interpretable under the method actually used.
- Derivation and calibration
- Referenced raw observations, analytical protocol, calibration record and conversion procedure Allows an agent to trace a displayed salinity value back to evidence.
- Uncertainty and validity
- Uncertainty interval with stated confidence basis; within method range, extrapolated, suspect or unknown Determines whether a difference or threshold crossing is sufficiently supported.
- Observation coverage
- Sampling time, location, depth or soil horizon, and represented spatial or temporal extent Prevents a local sample from being treated as representative of an entire water body or root zone.
- Use-specific salinity class
- Class assigned by a named scheme, or unclassified Connects a measurement to a particular use without treating a classification as universal.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 19 findings · 32 questions.
Salinity meaning Establishes which salt-related quality an observation expresses.
Salinity conventions cannot be treated as interchangeable names for one numeric quantity.
Definition and convention
Records the operational definition and the community or authority using it.
Declared salinity quantity
Identify whether the observation expresses salt content, Practical Salinity or a declared proxy, preserving its source terminology.
- What exactly does salinity mean in this record, and which discipline or authority defines that meaning? definition
- Which source establishes the scale, denominator and reporting convention used? provenance
Adjacent qualities
Separates salinity from related measurements and hazards.
Proxy and hazard boundaries
Keep conductivity, dissolved-solids measurements and sodium-related indicators explicitly related to salinity rather than silently equating them.
- Is this record reporting salinity itself, a conductivity or dissolved-solids proxy, or an individual-ion property? boundary
- What evidence supports interpreting this proxy as salinity for the sampled medium? provenance
Sample and representation Connects a salinity observation to the material and extent it represents.
Salinity interpretation depends on whether the sample is ambient water, pore water or a prepared extract.
Medium and preparation
Identifies the sampled phase and any preparation that changes its relationship to the original medium.
Sample basis
Record water source or soil horizon and distinguish direct sampling from laboratory extraction.
- Does the value describe ambient water, soil pore water, a saturation extract or another prepared solution? definition
- What extraction ratio, saturation procedure, dilution or preservation step was used? measurement
Spatial and temporal support
Defines the location, depth and period represented by the observation.
Salinity coverage
Distinguish a point reading from a profile, composite sample or average across changing conditions.
- At what time, location and water depth or soil horizon was salinity sampled? measurement
- What evidence permits extending this value across a water column, field, root zone or reporting period? boundary
Measurement and conversion Makes the route from observation to reported salinity inspectable.
A plausible salinity number may still rely on an unsuitable calibration, composition assumption or conversion.
Analytical evidence
Captures the underlying measurement and its quality controls.
Method and calibration
Retain the analytical method, raw readings, calibration evidence and operating conditions behind the salinity result.
- Which raw measurements and analytical method produced the reported salinity? measurement
- Which calibration records and checks demonstrate that the method was suitable for this sample and range? provenance
- What temperature, pressure or reference-temperature corrections were applied? measurement
Conversion validity
Controls transformations between reporting conventions and proxies.
Justified transformation
Require a named transformation, its inputs and an applicability assessment while retaining the original observation.
- What equation, software version and auxiliary inputs were used to convert the original value? provenance
- Are the sample composition and measurement conditions within the transformation's supported domain? boundary
- What uncertainty should accompany the converted estimate, including uncertainty in any composition assumption? measurement
Variation and interpretation Determines whether salinity differences reflect environmental change or incompatible observations.
A salinity gradient or trend is meaningful only when its observations can support that comparison.
Comparable observations
Assesses compatibility before calculating differences or trends.
Supported salinity change
Separate changes in salinity from changes in scale, extraction procedure, sampling coverage or instrument behaviour.
- Do the compared values use compatible conventions, sample preparation and spatial or temporal coverage? boundary
- Does the observed difference exceed the combined measurement uncertainty and relevant sampling variability? measurement
Change explanations
Links changes to candidate mechanisms without making salinity alone establish causation.
Salt and water balance hypotheses
Record candidate explanations involving water balance, salt movement or phase changes and identify the evidence needed to distinguish them.
- What independent observations distinguish evaporation, dilution, saline inflow, salt dissolution or another proposed explanation? provenance
- Which additional flow, water-level, ion-composition or profile measurements would discriminate among the remaining explanations? action
Use and response Connects salinity evidence to a specified use and proportionate next action.
The significance of salinity depends on the receiving system, intended use and applicable decision rule.
Contextual classification
Anchors classes and thresholds to their intended application.
Applicable salinity criterion
Associate each classification with its authority, medium, measurement convention and relevant receptor or use.
- Which named classification or threshold applies to this use, organism, crop or receiving system? provenance
- Does the criterion require the same salinity convention, sampling basis and exposure period as the available observation? boundary
Response evidence
Determines whether to seek more evidence, monitor or refer a supported concern for intervention.
Salinity-informed action
Record the decision supported by salinity evidence, unresolved dependencies and a follow-up measurement capable of assessing the response.
- Does the evidence support continued monitoring, confirmatory sampling or evaluation of a salinity-management intervention? action
- Which additional composition, sodicity, organism-response or process constraints must be checked before selecting an intervention? boundary
- What subsequent salinity observation, using which convention and sampling basis, would demonstrate the intended result? measurement
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- The registry gives no sense; this description covers the measurable salt-content property across water and soils.
- Freshwater, brackish and saline category boundaries vary by discipline and classification system.
- This is recall, not source-verified research; check exact standard scope, measurement conventions and application-specific thresholds before publication.
- Which of these check these first hold for the sense of salinity this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Practical Salinity of seawater, derived from conductivity
- Absolute Salinity of seawater, expressed as a mass fraction
- Reference Salinity under the reference seawater composition convention
- Freshwater salinity
- Soil salinity, commonly assessed through extract conductivity
- Which of these kinds and varieties hold for the sense of salinity this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Oceanographic salinity notation - S_P, S_A, S_R - Symbols for Practical Salinity, Absolute Salinity and Reference Salinity respectively; these identify different quantities, not interchangeable units.
- Which of these identifiers and schemes hold for the sense of salinity this model covers, and on what evidence? provenance
Standards and regulation
Recalled without web access and unsourced; every item is a lead to verify.
- Practical Salinity Scale 1978 (PSS-78), documented through UNESCO oceanographic standardisation.
- Thermodynamic Equation of Seawater 2010 (TEOS-10), adopted by the Intergovernmental Oceanographic Commission and developed with SCOR and IAPSO.
- Which of these standards and regulation hold for the sense of salinity this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Calculating seawater density and interpreting ocean circulation.
- Monitoring estuarine mixing and saltwater intrusion into groundwater.
- Assessing irrigation water and soil conditions for crop production.
- Managing aquatic habitats and aquaculture.
- Monitoring desalination feedwater, product water and brine.
- Which of these real-world use hold for the sense of salinity this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Practical Salinity - Open-ocean surface water commonly about 30-37; standard PSS-78 validity covers 2-42. - Dimensionless; often informally labelled PSU.
- Absolute Salinity - Ordinary ocean water is approximately 35 g/kg, with substantial regional variation. - g/kg
- Electrical conductivity of a soil saturated-paste extract - A traditional saline-soil classification uses a threshold of 4 dS/m at 25 °C; crop effects can occur below this. - dS/m
- Which of these typical measurements hold for the sense of salinity this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Treating Practical Salinity, salt mass fraction and total dissolved solids as numerically interchangeable.
- Converting conductivity to salinity without accounting for temperature, ionic composition and the applicable calibration range.
- Comparing soil conductivity measurements made with different extraction methods as though they used the same scale.
- Elevated salinity can impair crop water uptake and stress freshwater organisms.
- Saltwater intrusion can reduce the suitability of groundwater for drinking and irrigation.
- Which of these failure modes and hazards hold for the sense of salinity this model covers, and on what evidence? provenance
Regional variation
Recalled without web access and unsourced; every item is a lead to verify.
- Evaporation-dominated waters tend to be saltier, while precipitation, river inflow and ice melt tend to lower salinity.
- Seawater composition varies geographically, so conductivity alone does not always determine Absolute Salinity accurately.
- Soil salinity is particularly important in arid and semiarid irrigated regions where salts accumulate under inadequate drainage.
- Which of these regional variation hold for the sense of salinity this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Total dissolved solids - Includes dissolved material beyond salts and depends on the analytical method; it is not universally equivalent to salinity.
- Electrical conductivity - Measures electrical transport and serves as a salinity proxy; temperature and ion composition affect the relationship.
- Sodicity - Concerns sodium's relative abundance, especially on soil exchange sites, rather than total salt content.
- Hardness - Primarily measures calcium and magnesium contributions; highly saline water need not be proportionately hard.
- Chlorinity - Measures halide content under a defined convention and estimates salinity only through an assumed compositional relationship.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of salinity this model covers, and on what evidence? provenance
What the second pass must settle
- Which disciplinary definitions and reporting conventions must this registry entry explicitly support beyond oceanography and soil-water assessment?
- How should legacy values labelled ppt, PSU or percent be interpreted when their scale or denominator is undocumented?
- Which conductivity-to-salinity or dissolved-solids conversions are validated for the nonmarine waters and concentrated brines encountered by intended users?
- Which soil extraction methods can be related through locally validated conversions, and where must their results remain incomparable?
- Which application-specific classification authorities and exposure periods should govern decisions in the intended deployments?