A question about CLM's reconciliation of changes in area for different land units

[liliyao]

Hi,

In the development version of CLM (e.g., ctsm5.1.dev118), the variables PCT_CROP, PCT_URBAN, and PCT_LAKE appear on the transient landuse file, while the variables PCT_NATVEG, PCT_WETLAND, and PCT_GLACIER do not appear. I am interested in understanding how CLM reconciles changes in area among these three land units. And could you please direct me to the relevant code sections that explain their dynamic changes when running CLM with IHIST components (HIST_DATM%GSWP3v1_CLM50%BGC-CROP_SICE_SOCN_SROF_SGLC_SWAV)?

Thank you very much!

 

[slevis]

In your ctsm directory,
- the code for generating fsurdat and landuse files is in /tools/mksurfdata_map/src
- the code for reading fsurdat and landuse files is in /src/main/surfrdMod.F90

Pull Request

Enable the mksurfdata_map to generate landuse_timeseries for dynamic urban and lake by billsacks · Pull Request #1586 · ESCOMP/CTSM

Note about this PR This PR is a continuation of #1579 (from @keerzhang1). I approved that PR in terms of the work needed from @keerzhang1, but there is still some work needed on our end, primarily ...

github.com

likely contains plenty of useful information.

Transient lakes and urban will be available in ctsm5.2. Are you sure that they are also available in ctsm5.1? I see evidence for them in ctsm5.1, but I don't think I see corresponding code in the mksurfdata_map tool. In any case, this is the type of search for information that you can perform on your own. Github has a search GUI, and unix and git have a very useful tool for searching code: "grep" and "git grep".

 

[liliyao]

In your ctsm directory,
- the code for generating fsurdat and landuse files is in /tools/mksurfdata_map/src
- the code for reading fsurdat and landuse files is in /src/main/surfrdMod.F90

Pull Request

Enable the mksurfdata_map to generate landuse_timeseries for dynamic urban and lake by billsacks · Pull Request #1586 · ESCOMP/CTSM

Note about this PR This PR is a continuation of #1579 (from @keerzhang1). I approved that PR in terms of the work needed from @keerzhang1, but there is still some work needed on our end, primarily ...

github.com

likely contains plenty of useful information.

Transient lakes and urban will be available in ctsm5.2. Are you sure that they are also available in ctsm5.1? I see evidence for them in ctsm5.1, but I don't think I see corresponding code in the mksurfdata_map tool. In any case, this is the type of search for information that you can perform on your own. Github has a search GUI, and unix and git have a very useful tool for searching code: "grep" and "git grep".

Thank you, Sam! I was looking for how CLM updates landunit weights when handling dynamic landunit , and I found that it is located in the file "/src/dyn_subgrid/dynLandunitAreaMod.F90". Thanks!