Add tunable aerosol diameter thresholds for renaming to strat coarse mode in MAM5 #7795
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mingxuanwupnnl
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hwangacme,
keziming,
wlin7 and
xuezhengllnl
mingxuanwupnnl
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| <entry id="dp_xferall_thresh_accum_rename" type="real" category="scavenging" | ||
| group="phys_ctl_nl" valid_values="" > | ||
| accum mode aerosol diameter threshold for renaming to strat coarse mode |
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@mingxuanwupnnl . Can you make the descriptions for these two namelist variables distinguishable?
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@mingxuanwupnnl @wlin7
dp_cut
Cutoff (geometric-mean) diameter for a lognormal mode. When growth pushes a mode’s mean size above dp_cut, the excess tail is shifted to the next larger mode. Applied each timestep to keep each mode’s mean/width physically reasonable.
dp_xferall_thresh
“Full-transfer” trigger. If the updated mean diameter of a mode exceeds this threshold, the entire mode (mass/number) is transferred to the next larger mode. This is a safety valve for runaway growth that dp_cut could not contain over prior steps.
Example: If the new mean diameter is 0.8 µm and dp_xferall_thresh = 0.6 µm, the mode is fully transferred—preventing an unphysical, oversized mean in that mode.
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@mingxuanwupnnl Based on Ziming's explanation, I suggest using the following brief description for the two namelist variables:
dp_cut_accum_rename: Cutoff diameter for larger accum mode particles renamed to the strat coarse mode
dp_xferall_thresh_accum_rename: Threshold diameter for all accum mode particles transferred to the strat coarse mode
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Remove the [WIP] from the title. If it still is in progress, convert it to a draft PR. (link is under Reviewers). |
mingxuanwupnnl
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components/eam/bld/build-namelist
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| add_default($nl, 'mam_amicphys_optaa'); #for enabling amicphys code in eam | ||
| add_default($nl, 'n_so4_monolayers_pcage'); #number of so4(+nh4) monolayers needed to "age" a carbon particle | ||
| add_default($nl, 'dp_cut_accum_rename'); | ||
| add_default($nl, 'dp_xferall_thresh_accum_rename'); |
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@mingxuanwupnnl please add a brief description of the two namelist variables here.
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| <entry id="dp_xferall_thresh_accum_rename" type="real" category="scavenging" | ||
| group="phys_ctl_nl" valid_values="" > | ||
| accum mode aerosol diameter threshold for renaming to strat coarse mode |
There was a problem hiding this comment.
@mingxuanwupnnl Based on Ziming's explanation, I suggest using the following brief description for the two namelist variables:
dp_cut_accum_rename: Cutoff diameter for larger accum mode particles renamed to the strat coarse mode
dp_xferall_thresh_accum_rename: Threshold diameter for all accum mode particles transferred to the strat coarse mode
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The changes look good and consistent. e3sm_atm_integration tests for default configuration passed BFB against master baselines. The new tuning also tested in a new coupled configuration.
…7795) Add tunable aerosol diameter thresholds for renaming to strat coarse mode in MAM5 When using CMIP7 volcanic SO2 emission, the model will produce larger stratospheric AOD and sulfate burden due to increased emission amount as well as changing injection height. The stratospheric sulfate burden during Pinatubo eruption when using CMIP7 volcanic SO2 emission is larger than HIRS observations. For v3.HR simulations, we identified two tunable aerosol mode diameter thresholds for renaming accumulation mode (mode 1) sulfate to stratospheric coarse mode (mode 5). By changing them from 0.4 um to 1 um, changing the dgnumhi in mode 1 physprop file, and changing dgnumlo in mode 5 physprop file, the stratospheric AOD and sulfate burden during Pinatubo are reduced, the RESTOM and SW flux at TOA are also reduced to the level when using default CMIP6 volcanic emission. In this PR, we only introduce two namelist variables for the two tunable thresholds and keep values the same as v3.LR simulations. [BFB] [NML] Two new namelist variables introduced affecting all tests using EAMv3
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Merged to next. |
Add tunable aerosol diameter thresholds for renaming to strat coarse mode in MAM5
When using CMIP7 volcanic SO2 emission, the model will produce larger stratospheric
AOD and sulfate burden due to increased emission amount as well as changing injection
height. The stratospheric sulfate burden during Pinatubo eruption when using CMIP7
volcanic SO2 emission is larger than HIRS observations.
For v3.HR simulations, we identified two tunable aerosol mode diameter thresholds
for renaming accumulation mode (mode 1) sulfate to stratospheric coarse mode (mode 5).
By changing them from 0.4 um to 1 um, changing the dgnumhi in mode 1 physprop file,
and changing dgnumlo in mode 5 physprop file, the stratospheric AOD and sulfate
burden during Pinatubo are reduced, the RESTOM and SW flux at TOA are also reduced
to the level when using default CMIP6 volcanic emission.
In this PR, we only introduce two namelist variables for the two tunable thresholds
and keep values the same as v3.LR simulations.
[BFB]
[NML] Two new namelist variables introduced affecting all tests using EAMv3
Testing results.