Summary of the Article:

## CLM-CN Pool Structure, Rate Constants, and Parameters

The CLM-CN model in CLM45 uses three state variables for fresh litter and four state variables for soil organic matter (SOM). The model does not explicitly represent the masses of carbon and nitrogen in the live microbial community, but their activity is captured through decomposition fluxes transferring mass between the litter and SOM pools, and associated heterotrophic respiration losses.

The litter and SOM pools are arranged in a converging cascade, derived from the Biome-BGC v4.1.2 implementation. Model parameters are estimated based on a synthesis of microcosm decomposition studies using radio-labeled substrates.

The article provides tables listing the base decomposition rate constants for each litter and SOM pool, as well as the physical fragmentation rate for the coarse woody debris (CWD) pool. The rates are presented for both the Biome-BGC daily timestep and the typical CLM-CN one-hour timestep, with the transformation explained.

Additionally, the article includes a table of respiration fractions for the decomposition fluxes out of each litter and SOM pool. These respiration fractions were estimated simultaneously with the exponential decay rates from the microcosm decomposition experiments.