This file describes some details for the multilayer canopy model (CLM-ml.v1) and its use in offline (uncoupled) simulations.

This is the code described in:

Bonan, G.B., E.G. Patton, J.J. Finnigan, D.D. Baldocchi, and I.N. Harman. 2021. Moving beyond the incorrect but useful paradigm: reevaluating big-leaf and multilayer plant canopies to model biosphere-atmosphere fluxes – a review. Agricultural and Forest Meteorology, https://doi.org/10.1016/j.agrformet.2021.108435.

1. Directory structure

   a. The main multilayer canopy model code is in the directory:

   1. multilayer_canopy

   Model variables are defined in MLCanopyFluxesType.F90 Model physical constants are defined in MLclm_varcon.F90 Model parameters (array dimensions) are defined in MLclm_varpar.F90 Model run control variables are defined in MLclm_varctl.F90

   This code needs to be moved to the CLM5 mods directory when coupled to CLM5

   b. There are two directories for the uncoupled simulations:

   1. offline_driver = driver code for the offline case. The main driver is CLMml.F90
   2. offline_executable = directory containing the makefile, executable, and namelists

   The offline code (uncoupled to CLM5) has a namelist file read in offline_driver/controlMod.F90. This namelist file sets the tower site, the year, and the month of the simulation. The code controlMod.F90 also sets the directories for the tower forcing files, the clm history files, and the output files.

   c. The following directories are dummy CLM5 stub code only used in the offline case:

   1. cime_src_share_util = dummy CLM5 stub code from: cime/src/share/util
   2. clm_src_biogeophys = dummy CLM5 stub code from: components/clm/src/biogeophys
   3. clm_src_cpl = dummy CLM5 stub code from: components/clm/src/utils
   4. clm_src_main = dummy CLM5 stub code from: components/clm/src/main
   5. clm_src_utils = dummy CLM5 stub code from: components/clm/src/utils

   When coupled to CLM5, the CLM5 code is used instead. Some files need to be modified to couple with the multilayer canopy.

   d. The RSL psihat look-up file is in the directory:

   1. rsl_lookup_tables

2. Run the model for a particular tower site.

   Input files are provided to run the model (offline) for the US-UMB tower site for July 2006. From offline_executable, use the command:

   ./prgm.exe < nl.US-UMB.2006

   Input files are read from the input_files directory Model output is written to the output_files_directory