InMAP evaluation - single elevated source emission scenario

[bkoo-git]

This page is created to share/archive discussions on an InMAP test run with a single elevated source.

The test run simulated dispersion of primary PM2.5 emissions from a refinery point source in the East Bay, and the results were compared with those from CALPUFF modeling. The model results and an issue in the InMAP plume rise are summarized here: InMAP_evaluation_single_source.pptx

Tagging @marshalljulian @bujinb @pmartien @dholstius @stephenreid65 @ctessum to include in the discussion.

[bkoo-git]

As suggested in the 20230426 meeting, additional test runs were conducted to further examine the plume rise issue where the stack exit temperature was set equal to the ambient temperature in order to disable buoyancy force. The results suggest a possible issue in the buoyancy-driven plume rise calculation. The test run results are summarized here: diag_plume_rise_issue.pptx

[marshalljulian]

Thanks! This looks good -- it looks like that shift removes the problem, exactly as hoped for. Yes? (In your mind, is this now "fixed", or is it something we should work on further?)

The model may now be underestimating plume-rise in those months, since the model is simulating only inertial rather than buoyancy -driven forces, but that physical mechanism is what it's simulating the other months of the year anyway.

best, Julian

On Tue, May 2, 2023 at 1:01 PM bkoo-git @.***> wrote:

As suggested in the 20230426 meeting, additional test runs were conducted to further examine the plume rise issue where the stack exit temperature was set equal to the ambient temperature in order to disable buoyancy force. The results suggest a possible issue in the buoyancy-driven plume rise calculation. The test run results are summarized here: diag_plume_rise_issue.pptx https://github.com/BAAQMD/InMAP-SFAB/files/11377303/diag_plume_rise_issue.pptx

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[ctessum]

Thank you!

Would you be willing also post or link to this issue in https://github.com/spatialmodel/inmap/issues ? I may be able to find someone to work on fixing it. (Not immediately, though, so if someone else wants to fix it first that is welcome.)

It's possible that we've implemented the buoyancy plume rise incorrectly, or it may be that the ASME plume rise model that we're using is not as good as the Briggs one that SMOKE uses (and probably calpuff too).

[ctessum]

Just to remind myself, here is a paper of different alogrithms that we can try when we get around to it: https://acp.copernicus.org/articles/18/14695/2018/

[bkoo-git]

@marshalljulian I wouldn't say it fixed the problem: the test was rather intended to help identify which part of the calculation was causing the issue. I don't think that plume rises in other months are mainly momentum-driven. For momentum forces to dominate, the temperature difference (exit temp - ambient temp) must be less than 50 K (see here); however, the temp differences are greater than 200 K in all months. I also conducted the test for a summer month (June), and the result shows that removing the buoyancy force leads to a significantly overestimated surface layer concentration at the source location (underestimating plume rise means overestimating surface layer concentrations). Here's the result: diag_plume_rise_issue_2.pptx

@ctessum I've posted a link to this page in https://github.com/spatialmodel/inmap/issues/117.