Add the soil erosion model

[tanzeli1982]

Add the soil erosion model to ELM. The changes include the implementation
of soil erosion and erosion induced sediment, C, N and P fluxes from land to rivers.

[BFB]
[NML]

[tanzeli1982]

It is a BFB and NML PR. The code review page for this task can be found here https://acme-climate.atlassian.net/wiki/spaces/ED/pages/976486494/B1+Soil+Erosion.

[bishtgautam]

@tanzeli1982, The output of the command shows your PR is BFB and please update the first comment of this PR to indicate it is BFB. (see https://acme-climate.atlassian.net/wiki/spaces/ED/pages/16253965/Commit+and+PR+message+template). Also, update the first comment to include the link the code review page as requested by @rljacob.

[bishtgautam]

@tanzeli1982, If a question in a comment has been answered, don't delete the comment. Let the comment remain, so someone at a later date can follow the conversation.

[tanzeli1982]

@qzhu-lbl said

One comment is about ColPBalanceCheck 665
primary P and occluded P are not accounted, in
col_poutputs, since they are not tracked in the P balance calculation.

[tanzeli1982]

@bishtgautam I have copied three raw data files (mksrf_gravel_10level_5min.c190603.nc, mksrf_slope_10p_0.5x0.5.c190603.nc and mksrf_soilero_0.5x0.5.c190603.nc) to /global/project/projectdirs/acme/inputdata/lnd/clm2/rawdata.

[bishtgautam]

@tanzeli1982, The data has been now added to E3SM inputdata server and is available at https://web.lcrc.anl.gov/public/e3sm/inputdata/lnd/clm2/rawdata/

[thorntonpe]

@tanzeli1982 I'm beginning my review of this PR. The design document indicates that this capability is added for the ECA bgc model. Is it also added for CTC? Since CTC is the default soil bgc formulation, it should also be the default for your new capabilities. Tagging @kvcalvin for clarification, if needed.

[kvcalvin]

@tanzeli1982 and @thorntonpe: If this feature is intended to be run in v2, then it will need to be incorporated into the CTC model as that is the soil BGC formulation for v2.

[tanzeli1982]

@thorntonpe @kvcalvin It was tested on ECA but works for both.

[thorntonpe]

@tanzeli1982 Can you provide more details on what "tested on ECA, but works for both" means? Does the design document need to be modified to reflect this assessment?

[tanzeli1982]

@thorntonpe It means that the soil erosion model does not rely on the implementation of any BGC scheme because it uses the general C, N and P state and flux interfaces in data_types/ColumnDataType.F90 and ECA or CTC is not the condition for any part of the code. I will modify the documentation to make it clear.

[thorntonpe]

@tanzeli1982 Thanks for the clarification. Does this PR include soil erosion model parameters that have been set on the basis of comparing simulation output to observations?

[tanzeli1982]

@thorntonpe There are three variables (parEro_c1, parEro_c2 and parEro_c3) in the surface data that are soil erosion parameters from calibration. The model data comparison is now in the code review page.

[bishtgautam]

@tanzeli1982 The merging of the master branch into a feature branch is highly discouraged. Is there a reason you did this merge?

[tanzeli1982]

@bishtgautam I was not aware of the risk of this operation. How could I revert the commit?

[rljacob]

Do a hard reset on your branch to the commit before you did that merge.
git reset --hard 0b9a938

Then force push the branch to github
git push --force origin tanzeli/lnd/elm-erosion-master

[tanzeli1982]

@rljacob Thank you very much.

[tanzeli1982]

@bishtgautam should we move this PR forward? Kate has approved the design document.

[bishtgautam]

@thorntonpe, @qzhu-lbl, Could you review this PR? thanks

[rljacob]

2 PET tests failed and I don't think this PR can be ruled out as the cause:
PET_Ln9_PS.ne30_oECv3_ICG.A_WCYCL1850S.sandiatoss3_intel.allactive-mach-pet
PET_Ln5.ne4_ne4.FC5AV1C-L.sandiatoss3_intel.allactive-mach-pet

@bishtgautam please run a PET test with an I case that uses this code.

[bishtgautam]

Both PET tests passed on Compy using this feature branch.