# ADR-NNNN: <Title>

| Field         | Value                                          |
|---------------|------------------------------------------------|
| Kind          | ADR                                            |
| Status        | Draft \| Accepted \| Superseded \| Deprecated  |
| Decided       | YYYY-MM-DD (or "historical")                    |
| Deciders      |                                                |
| Supersedes    | ____ (if any)                                  |
| Superseded by | ____ (if any)                                  |

## Context

*What forced this decision, and the constraints actually in play — architecture, HPC /
cluster environment, scientific correctness (adjoint, mass conservation, reproducibility),
external obligations (WMO / Copernicus / UNFCCC), backward-compat promises. Enough that a
maintainer who wasn't there can reconstruct the situation. Assume they do NOT have it in
their head.*

## Decision

*What we chose, in the present tense as a standing rule: "We use X, not Y."*

## Consequences

*What this buys us, what it costs, and — most importantly — what it now forbids or
constrains: the "never do Z, because…" a newcomer would otherwise trip over. Note any
follow-up that would require a new RFC.*