Here is a concise summary of the article:

## Model Equilibration and Acceleration

The article discusses the equilibration process required for transient experiments in carbon cycle models. To satisfy the assumption that productivity is balanced by ecosystem carbon losses, the model must be "spun up" until it reaches a stable long-term equilibrium.

However, due to the coupling between slow soil organic matter (SOM) pools and productivity, the standard equilibration process can be extremely slow, particularly for models with a passive SOM pool. To accelerate equilibration, the article describes a modified "accelerated decomposition" approach.

The key aspects of this approach are:

1. Accelerating the base decomposition rates (ki) of the various pools by a factor (ai) to collapse the slow pools onto an annual timescale.
2. Accelerating the vertical transport terms and radioactive decay (when 14C is enabled) by the same factor (ai).
3. Applying a geographic term (al) that increases the acceleration at higher latitudes, where decomposition is slower.

When transitioning out of the accelerated mode, the pool concentrations are multiplied by the inverse of the acceleration factors (1/ai) to bring the model back to approximate equilibrium.

This accelerated equilibration approach allows the model to rapidly reach a stable state while preserving the essential dynamics of the full model, enabling efficient initialization for transient experiments.