A new physically based dust emission scheme with more aeolian physics #1712
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dmleung
changed the title
…ric soil moisture threshold to the equation by Fecan et al. (1999)
Major changes include: 1. Use Shao et al. (2000) dust emissions threshold scheme instead of Iversen and White (1982) scheme. 2. Use Kok et al. (2014) dust emission scheme instead of Zender et al. (2003) scheme. 3. Change the optimal soil diameter of 75 micrometer to 130 micrometer. 4. Change the threshold LAI value of dust emission (from 0.3) to 1 (or 0.5 is also acceptable). 5. Add the drag partition effect due to rocks (using the roughness factor input data) and plants (using CLM LAI). 6. Remove Owen effect which is less relevant to the dust emission process. 7. Add the dust emission intermittency effect due to the PBL turbulence. Other code changes: 8. Add multiple variables for output. 9. Pull out some major dust emission calculations out of the if loop (if lnd_frc_mbl > 1) so that variables are outputted regardless of the possibility of saltation and dust emission.
ekluzek
added
type: enhancement
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Adding @jfkok to this issue.. |
Update externals for cism and cime to cesm2.1.4-rc-10. cime update was needed to run on izumi. iAdds a compset for the smyle L83 model (both 1850 and transient). BWsc1850smyle (jedwards4b) Add SSP3-7.0 extension compset and use-case, that runs for fixed 2100 conditions with 2100 landuse and 2100 harvest and fertilizer. Update Nitrogen-deposition datasets with files created from WACCM simulations for SSP scenarios (SSP3-7.0, SSP5-3.4, and SSP5-8.5). Fix several issues.
Update externals for cism and cime to cesm2.1.4-rc-10. cime update was needed to run on izumi. iAdds a compset for the smyle L83 model (both 1850 and transient). BWsc1850smyle (jedwards4b) Add SSP3-7.0 extension compset and use-case, that runs for fixed 2100 conditions with 2100 landuse and 2100 harvest and fertilizer. Update Nitrogen-deposition datasets with files created from WACCM simulations for SSP scenarios (SSP3-7.0, SSP5-3.4, and SSP5-8.5). Fix several issues.
…o the alternative clay fraction dataset from SoilGrids. CLM will use its own clay dataset. (dmleung edited 11 Jul 2022)
…om SoilGrids (edit 11 Jul 2022).
…e the drag partition effect to CTSM's own land cover: land use harmonization 2 (LUH2). dmleung will double check if the equations are implemented correctly. 24 Jul 2022
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The surface roughness file used is here on cheyenne: /glade/u/home/dleung/CESM2/myinput/nas_cleared/F_eff_r_static_mean_allLAI-09x125-12172021.nc This is based on the 2005 Prigent data which was at a quarter degree and interpolated using area weighted mean. The 2012 Prigent data is used in the Ronny Meir work and is at 6km resolution. |
dmleung talked to ekluzek and changed the index of wt_lunit in DUSTMod.F90. It is correct to use natveg_lb:natveg_ub instead of natveg_size to denote the indices of wt_lunit. In calculating the land cover fraction of bare soil, noveg is is used instead of natveg_lb. dmleung also added a history field for diagnostics of the standardized fluid threshold friction velocity (m/s) for the dust emission scheme in DUSTMod.F90.
dmleung updated the parameters within the dry fluid threshold scheme of Shao and Lu (2000) to be consistent with dmleung's dust emission scheme paper. dmleung also removed most of the relevant paths of the existing land cover dataset to stick with the LUH2 land cover within CLM.
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@ekluzek here are my thoughts (italics) to some of your questions (in bold) from email:
Which Prigent data should we use for the end result: Meier, Leung, or original Prigent?
Should we bring in Prigent dataset all at once with the Dust work, or as an incremental improvement after the resolution dependent version is brought in?
I'll let CAM and CAM-CHEM people respond to questions about what parameterizations and name list options we want to maintain, especially for paleo configurations. |
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We have a new branch for this work based off the latest development version of the model ctsm5.1.dev106 (dustemis_dev). I moved the changes here to it by doing the following... git diff release-clm5.0.34 > dust.diff
$EDITOR dust.diff # To correct the paths for namelist_definition and lnd_import_export.F90...
git apply -3 dust.diff
$EDITOR src/biogeochem/DUSTMod.F90 src/biogeophys/SoilStateInitTimeConstMod.F90 src/cpl/mct/lnd_import_export.F90 src/main/controlMod.F90. # Fix the conflictsAfter we get that branch working and in place for a PR, we'll close this one. |
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@dmleung has successfully run a case with CAM for the new development version branch, and shown that the results are similar to the previous clm5.0 case. This will allow us to open a new PR for that branch, and close this one. The new branch is very close to the very latest development version based off of ctsm5.1.dev106 which is only 7 tags behind the latest. This is all very good news. Here's the plot he gave me...
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This is being replaced by #1897. So I'm closing this one. |
Description of changes
This is a scheme that builds upon issue #1230 and #1604 which switched CESM2's default dust emission scheme (Zender et al., 2003) to a more physical and less empirical one (Kok et al., 2014). Based on #1230 's edits, #1604 's modifications add new aeolian physics to the Kok's scheme, most notably, by adding the roughness effect (or called drag partition effect) which discounts surface soil erosion by winds due to the presence of local-scale land-surface roughness elements (mostly plants and rocks). We use a hybrid approach to account for both roughness from rocks (with a 2-D time-invariant dataset we provide) and roughness from plants (time-varying, as a function of CLM's LAI). We further include the dust emission intermittency effects due to boundary-layer turbulence.
Changes in files mainly include:
clm/src/biogeochem/DUSTMod.F90
clm/src/biogeophys/SoilStateType.F90
clm/src/biogeophys/SoilStateInitTimeConstMod.F90
clm/src/main/controlMod.F90
clm/src/main/clm_varctl.F90
clm/bld/namelist_files/namelist_definition_clm4_5.xml
user_nl_cam
user_nl_clm
Specific notes
One interesting thing is that CAM applies a source function (for Charlie Zender’s scheme) to the CLM dust emissions. In CESM, the dust emission calculation isn’t finished in CLM and is further processed in CAM before CAM calculates the transport. Because of this, when changing from Zender's scheme to Kok’s scheme one also needs to comment out the code block in CAM relevant to the source function. The relevant changes should be made in this file:
cam/src/chemistry/modal_aero/dust_model.F90
Two files below were changed when coupling to the atm model as a trick to avoid the very occasional occurrence of some negative downwelling LW radiation. The two files should ultimately not be merged with the master branch but are put here for documentation:
clm/src/main/lnd2atmMod.F90
clm/src/cpl/lnd_import_export.F90
Contributors other than yourself, if any:
@ekluzek
CTSM Issues Fixed (include github issue #):
Fixes #1604
Are answers expected to change (and if so in what way)? Only
Any User Interface Changes (namelist or namelist defaults changes)?
Yes. For now, mainly
clm/bld/namelist_files/namelist_definition_clm4_5.xml
Testing performed, if any:
The changes above were used to simulate an F case (F2000climo) coupling atm and lnd.
They have not been tested following the guideline yet.