Glossary

Attribution: The weight each source — observations, advected background, climatology — actually carried in a cell's analysis, exported by the analysis from the same arithmetic as the analysis field. It is derived, never authored: no module computes an attribution-like field from anything else, and the harness may not blend, smooth or paint one.
Background: The prior estimate the analysis starts from: the previous forecast advected to the valid instant. One of the three sources attribution accounts for.
Beat: One feature, developed end to end — specify, plan, tasks, analyze, implement — before the next begins. The sequence is the development plan.
Climatology: A long-run average field, computed from the truth subset over a declared window and committed as a build-step artefact with its provenance. The one truth-derived quantity the analysis may consume directly, and never the truth field at or near the valid instant. It is also a scoring reference, and what that costs in independence is recorded rather than hidden.
Computed: A figure produced by the model or the analysis, as against declared and derived. Typographically distinct, and it does not change kind between states.
Counterfactual: A replay of a run with exactly one thing changed — a profile dragged, an observation withheld, an instrument broken. Reversible in one action, and recorded in the manifest so that the edited run replays as faithfully as the original.
Declared: A value that came from configuration and was validated at startup. Horizons, grid size, timestep, frame budget, instrument noise, domain extents and the validity window of a forecast are all declared.
Derived: A figure diagnosed from computed state rather than integrated — most importantly the vertical structure, which in this version is displayed but not integrated. Every surface drawing a depth profile states that the levels between the model's own are derived.
Drift gate: The check that regenerates a committed artefact and fails the build on any difference, so that a change is attributed to the tree or to the upstream rather than guessed at.
Counterfactual: An edit a reader made, as a value: withhold a measurement, drag a profile, break an instrument, turn quality control off, redraw the track. Edits are applied in order to a fresh run and recorded in the manifest, so reverting is removing them rather than undoing them — which is why the recorded case comes back byte for byte.
Departure brief: The analysis at the quay-side instant, held constant and never refreshed: correct at issue and losing to the world on its own. The baseline every forecast is watched against. In the recorded case nothing has reported by then, so it is the background blended with climatology — which makes it a generous baseline rather than a straw man.
Ghost: The measured profile, kept drawn behind an edited one. A reader dragging a profile is stating what the instrument would have read, not erasing what it did read, and a picture that forgot the measurement would make the difference field meaningless.
Footprint: What the instruments did, drawn: the track and its measurements, and a needle or a depth-coded glyph for every profile. Built from the run's observations and from nothing else — it neither samples truth nor computes, so what it shows is what was measured rather than a picture of the answer.
Gate: A check that fails the build. Every gate is watched failing against a planted violation before it is trusted, and the commit that introduces it says so.
Horizon: A lead time at which a forecast is valid. Every horizon declared in configuration is rendered as a panel, and no panel is drawn for a horizon that is not declared.
Host time: Wall-clock elapsed time, read from the host to report how long the machinery took. It is marked as such wherever it is drawn and never enters a run, a manifest, or any simulation-time quantity.
Enlarge in place: Growing one panel while the other five stay visible and shrink to their declared minimum. Not a modal and not a new page: an enlargement that hid the row would be a slider with extra steps. It changes what is shown and never what is computed, and the test asserts that by object identity rather than by appearance.
Instrument: The simulated device through which — and only through which — the model may sample truth. It applies declared noise and declared error characteristics at a chosen position, depth and time.
Manifest: The complete description of a run: seeds, versions, digests and counterfactual state. The unit of export and import, and the thing a run is rebuilt from.
Issue time: The instant a forecast was made, and an axis of its own. The row is the lead-time axis; one scrubber above it is the issue-time axis. Moving it leaves every panel valid at the same moment and makes each a longer forecast of it, so the whole skill curve drops bodily. An analysis may see only observations with instants at or before its issue time.
Needle: A profile as drawn: a vertical line through the depth elevation extending exactly to the depth that probe reached, with a tick at every level it sampled and a barb where it carried on past the floor of the displayed volume. A profile that measured nothing is a cross at the surface instead, because a needle of no length would read as a probe that stopped there.
Observation: Truth sampled through an instrument. The type is opaque and has exactly one construction site, in the instruments module; there is no cast or helper anywhere else by which a truth value becomes one.
Ownship: The vessel the harness models: its own position, its sampling track, and the instruments on it. Its position is known, not inferred — which is the whole distinction this project holds to.
Persistence: The reference forecast that says tomorrow looks like today. One of the two references skill is reported against.
Panel: One horizon's view: the forecast field as an anomaly, the attribution layer, the absolute instants it is valid for and was initialised from, both skill figures in the scorer's own words, and the provenance one disclosure away.
Port: An interface with more than one conceivable implementation. There are four and there will not quietly be a fifth.
Recorded case: The run produced by the declared default seed: the one two readers are both looking at when they say "the recorded case". A reader may draw a new run instead, and the surface then says the run is no longer the recorded case.
Outside validity: A panel whose valid instant is past its forecast's declared validity window, or before the forecast was issued. It says so and draws nothing: there is no field to give it that would not be an extrapolation, and an extrapolation drawn beside five forecasts would read as one.
Row: The primary surface: one panel per declared horizon, in order, all visible at once. Not a slider — what is not on screen is what the eye forgets, and a claim about a trend delivered one frame at a time is a claim taken on trust. Not a grid — lead time is one-dimensional, and laying it out in two invents an ordering the data does not have.
Second channel: Whatever carries a distinction besides hue: here, a diagonal hatch over the cells where observations lead both other sources. It is what makes the attribution layer survive a monochrome print, and the margin it must clear is measured in luminance rather than asserted.
Skill: Performance relative to a reference, in the convention where zero means no better than the reference and negative means worse. Reported against persistence and against climatology, and the surface says so in those words when the model is not earning its compute.
Track: The path the vessel has travelled. Ordinary navigational English, not forbidden, and deliberately absent from the vocabulary gate's word list.
Truth record: A subsetted reanalysis field, converted to the project's own format by a script in the repository and committed as a derived artefact. The harness's claims are worth what its truth record is worth.

Words this project does not use

j-ocean holds no entity whose position it infers rather than knows, and the vocabulary gate enforces that. It also holds no customer, project or bid material anywhere — code, docs, data, commit messages or branch names. The forbidden list lives beside the gate; the half of it that names things which must not be written down is held as salted hashes rather than as words.