dz_min fix: need a long-term fix for this

[llpcarson]

See discussion with: #63

Hi, all. The fix is OK for now, but an issue needs to be opened indicating
the need for a long-term, more fundamental fix, noting the objections that @xi
Chen - NOAA Affiliate [email protected] and I have raised. The solution
lies in changes to the topography filtering for certain small islands or
peninsulas, and/or in fixes to the physics: previously the GWD was causing
crashes for us, and more recently @kai-yuan Cheng - NOAA Affiliate
[email protected] has found strange behavior in the deep convection
scheme causing a similar crash.

Lucas

On Mon, Jan 11, 2021 at 1:16 PM bensonr [email protected] wrote:

If the reason for the updates is satisfactory to everyone, I can finish up
the merge once I have formal reviews.

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
#63 (comment),
or unsubscribe
https://github.com/notifications/unsubscribe-auth/AMUQRVDWUUDKTQ5RXI46LVDSZM57JANCNFSM4VZIV6SQ
.

Originally posted by @lharris4 in #63 (comment)

[bensonr]

@lharris4 @LPCarson - the workaround was included in the dev/emc branch with PR #76. Is this acceptable or do we need to keep this issue open?

[lharris4]

EMC needs a long-term fix for this instead of just the dz_min workaround that was put in place to stabilize v16 just before implementation.

…

On Thu, Apr 15, 2021 at 11:14 AM bensonr ***@***.***> wrote: @lharris4 <https://github.com/lharris4> @LPCarson <https://github.com/LPCarson> - the workaround was included in the dev/emc branch with PR #76 <#76>. Is this acceptable or do we need to keep this issue open? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#64 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMUQRVG7WYRWB3CJETF7RYLTI37EZANCNFSM4V7ZGQGQ> .

[XiaqiongZhou-NOAA]

The "psm_bc(=1)" option is considered as a better fix . This part should be already in the dev/emc. We had done a lot of tests. It can efficiently fix the stability issue as "dz_min" but also have little impact on forecast performance. It fixed the similar issue for the regional applications. I got feedback from GSL that it also helped to fix their instability issue.

[bensonr]

@XiaqiongZhou-NOAA - if the psm_bc option is the preferable fix, I would like to remove the variable dz_min. It was a quick fix that will live on in infamy unless we prune it back.

[lharris4]

I'm not fond of the PSM but if it works for EMC and allows them to remove dz min, then all the better.

…

On Fri, Apr 16, 2021 at 10:26 AM bensonr ***@***.***> wrote: @XiaqiongZhou-NOAA <https://github.com/XiaqiongZhou-NOAA> - if the psm_bc option is the preferable fix, I would like to remove the variable dz_min. It was a quick fix that will live on in infamy unless we prune it back. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#64 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMUQRVHQY7RDJW7QKRTPSPLTJBCKPANCNFSM4V7ZGQGQ> .

[XiaqiongZhou-NOAA]

Yes, I think psm_bc is better since "dz_min" is an artificial limiter. But "dz_min" is in the original code (define =2), we only changed it to a parameter of input.nml for flexibility.

[bensonr]

I believe this has been fixed. Feel free to reopen if closed prematurely.