CNit Documentation

Welcome to the documentation for CNit (Carbon-Nitrogen Interactions in Terrestrial ecosystems), the coupled carbon-nitrogen cycle model for MAGICC (Model for the Assessment of Greenhouse Gas Induced Climate Change).

CNit is a process-based terrestrial biogeochemistry model that simulates the coupled dynamics of carbon and nitrogen cycles in terrestrial ecosystems. The model tracks carbon and nitrogen through plant, litter, soil, and mineral pools, with explicit representation of carbon-nitrogen feedbacks, environmental effects (CO₂ fertilization, temperature, land use change), and nitrogen limitation on carbon uptake.

Key Features:

Explicit carbon-nitrogen coupling with nitrogen limitation feedbacks
Four nitrogen pools (plant, litter, soil, mineral) and three carbon pools
Environmental modifiers: CO₂, temperature, land use, nitrogen availability
Separation of deforestation and afforestation for CDR scenarios
Annual timesteps use flux-allocation and pool-turnover fractions to represent within-year transfers
Evenly spaced subannual timesteps are also supported; allocation fractions apply within each timestep
Computationally efficient for integrated assessment modeling

Quick Navigation

🔬 For Scientists

Understand the model’s scientific basis, processes, and when to use CNit.

→ See CNit Model Overview for the model’s scientific basis and References for recommended publications.

→ See CNit Physics API for detailed scientific process descriptions and parameterizations.

📚 For Model Users

Install CNit and run your first simulation.

→ See Quickstart Guide for installation and basic usage.

→ See CMIP6 ESM emulation and TRENDY DGVM emulation for complete workflows, code, and outputs.

→ See CNit Physics API for detailed process equations and parameterizations.

→ See CNit Configuration API for model parameters and experiment inputs.

🛠️ For Developers

Contribute to CNit development.

→ See CNit Physics API for implementation details.

→ See Contributing for development setup and coding guidelines.

Model Overview

Learn about CNit’s structure, processes, scientific basis, and intended use.

Model overview

CNit Model Overview

Getting Started

Install CNit, then follow the basic usage guide to set up and run a simulation.

Getting started

Quickstart Guide

API Reference

Look up detailed process parameterizations, model calculations, configuration parameters, and class methods.

API reference

Emulation Workflows

Explore complete CMIP6 ESM and TRENDY DGVM emulation workflows, with notebooks and model outputs.

Emulation Workflows

Development

Read the release history and find guidance for contributing to CNit.

Development

Project Information

Find maintainer contact details, licensing and citation information, and related projects.

Project information