Title: 2.31. Carbon Isotopes — ctsm CTSM master documentation

URL Source: https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/Isotopes/CLM50_Tech_Note_Isotopes.html

Markdown Content:
CLM includes a fully prognostic representation of the fluxes, storage, and isotopic discrimination of the carbon isotopes 13C and 14C. The implementation of the C isotopes capability takes advantage of the CLM hierarchical data structures, replicating the carbon state and flux variable structures at the column and PFT level to track total carbon and both C isotopes separately (see description of data structure hierarchy in Chapter 2). For the most part, fluxes and associated updates to carbon state variables for 13C are calculated directly from the corresponding total C fluxes. Separate calculations are required in a few special cases, such as where isotopic discrimination occurs, or where the necessary isotopic ratios are undefined. The general approach for 13C flux and state variable calculation is described here, followed by a description of all the places where special calculations are required.

