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A bug fix for wet scavenging of aerosols and a minor modification for moisture property calculation#900

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grantfirl merged 2 commits into
NCAR:mainfrom
ChunxiZhang-NOAA:feature/p8c_cp
Apr 21, 2022
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A bug fix for wet scavenging of aerosols and a minor modification for moisture property calculation#900
grantfirl merged 2 commits into
NCAR:mainfrom
ChunxiZhang-NOAA:feature/p8c_cp

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@ChunxiZhang-NOAA
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A bug fix in mass flux divergence computation for wet scavenging of aerosols and a minor modification in moisture property calculation for the saSAS cumulus scheme. Please see issue #898. This bug fix was done by Jongil Han and Kate Zhang.

…erosols and a minor modification in moisture property calculation for the saSAS cumulus scheme
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Changes are correct.

Comment thread physics/samfdeepcnv.f
cj
tem = 0.5 * (xlamue(i,k)+xlamue(i,k-1)) * dz
tem1 = 0.25 * (xlamud(i,k)+xlamud(i,k-1)) * dz
tem = 0.25 * (xlamue(i,k)+xlamue(i,k-1)) * dz
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I am curious if the in-line SciDoc L1636 should be modified along with code change here, considering detraining parcel is not considered?

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There are 2 ways to compute a parcel property in updraft and downdraft: one is to consider only entrainment and the other is to take both entrainment and detrainment. For the former, the detrainment effect is taken into account by mass flux which is computed using entrainment and detrainment. Please see slide 4 & 8 for this PR. Note that mass flux divergence calculations are different for the former and the latter meothods. For the moisture transport, I changed the latter method to the former method in order to enhance moisture entrainment more easily (cq=1.3 in the code).

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Since only entrainment is considered to compute a parcel property in this update, the term "detraining" in Line 1636 and 1461 could be omitted.

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I don't get the "detraing" term. Please clarify.

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For example, In line 1636, the comments "...For the overshooting convection, calculate the moisture content of the entraining/detraining parcel ...". include "detraining" but the code does not use "xlamud" anymore. We want to make sure if this statement will be valid with this PR, since it will appear in CCPPv6 SciDoc.

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Since the 'detraining' effect is taken into account later in computation of mass flux divergence of moisture, I think the description is still ok.

Comment thread physics/samfdeepcnv.f
cj
tem = 0.5 * (xlamue(i,k)+xlamue(i,k-1)) * dz
tem1 = 0.25 * (xlamud(i,k)+xlamud(i,k-1)) * dz
tem = 0.25 * (xlamue(i,k)+xlamue(i,k-1)) * dz
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Pls confirm if SciDoc L1461 should be modified too.

Comment thread physics/samfshalcnv.f
cj
tem = 0.5 * (xlamue(i,k)+xlamue(i,k-1)) * dz
tem1 = 0.5 * xlamud(i) * dz
tem = 0.25 * (xlamue(i,k)+xlamue(i,k-1)) * dz
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check SciDoc L1405.

Comment thread physics/samfshalcnv.f
cj
tem = 0.5 * (xlamue(i,k)+xlamue(i,k-1)) * dz
tem1 = 0.5 * xlamud(i) * dz
tem = 0.25 * (xlamue(i,k)+xlamue(i,k-1)) * dz
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check SciDoc L1371

@ligiabernardet ligiabernardet added bug CCPP v6 Needed for CCPP v6 public release labels Apr 15, 2022
@mzhangw
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mzhangw commented Apr 15, 2022 via email

@grantfirl
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Really great documentation of the problem and fix via the powerpoint linked in the issue, thanks! The code changes look good to me.

@grantfirl grantfirl merged commit 860245c into NCAR:main Apr 21, 2022
@ChunxiZhang-NOAA ChunxiZhang-NOAA deleted the feature/p8c_cp branch April 22, 2022 15:45
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5 participants