Primordia Co.Grounded World Models

Appendix A Instantiation of Numerical Weather Prediction as a GWM

GWM element Numerical weather prediction counterpart
Explicit causal mechanism p Discretized Navier–Stokes + thermodynamics (known physics).
Grounding map g (Bayesian conditioning) Data assimilation: 4D-Var / ensemble Kalman filter over millions of daily observations (Kalnay, 2003).
Predictive distribution (PD) Ensemble forecast: perturbed initial conditions + stochastic physics.
Verified correctness / invariants Conservation of mass, energy, and momentum enforced by the integrator.
Predictability horizon Lyapunov limit on forecast lead time (Lorenz, 1963).
Table 1: Numerical weather prediction realizes the GWM contract element by element—the most mature deployed grounded world model.