IPE transport revisit

[twfang]

In order to understand the impact of 200km constrain on the model result, I have done two different runs. The default one is the current version of WAM-IPE while the other one results with removing the line of code.

All the results are the WAM-IPE simulation from 2013031600 to 2013031612 with time-varying drivers. This runs with self-consistent electrodynamics with Weimer 2005 at high-latitudes, the aurora is turned on, no plasma depletion is included.

It looks like everything behaves much better without the constrain. Also, the nighttime density becomes much larger when the constrain is taken away.

TEC:
Default (with 200km constrain)

Modified (no 200km constrain)

NE at 150km:
Default (with 200km constrain)

Modified (no 200km constrain)

O+ density at 0316 6UT
Default (with 200km constrain)

Modified (no 200km constrain)

Note that the scales are different in each plot!

O+ velocity at 0316 6UT
Default (with 200km constrain)

Modified (no 200km constrain)

O+ density at 0316 12UT
Default (with 200km constrain)

Modified (no 200km constrain)

O+ velocity at 0316 12UT
Default (with 200km constrain)

Modified (no 200km constrain)

[twfang]

Unfortunately, the model starts to produce NaNs after a longer test. George and I will have to look into the problem before we make any changes.

[gmillward]

NaN traced back to -ve Te at low altitudes for flux-tube mp=73, lp=46. The -ve Te then traced to an issue with q-coordinate interpolation in the ExB transport routine. Investigating the issue as it calls into question all of the q-coordinate interpolation in general (ie, has Q been calculated correctly for the IPE grid?)

Here are the q values at low altitudes for the flux-tubes around mp73 lp46

              Alt km      mp73 lp46    mp73 lp47    mp74 lp46  mp74 lp47

---

    0      90.0000     0.521460     0.499284     0.517652     0.495333

        1      92.0000     0.520902     0.498723     0.517095     0.494774
        2      94.0000     0.520344     0.498163     0.516538     0.494215
        3      96.0000     0.519787     0.497603     0.515982     0.493657
        4      98.0000     0.519230     0.497043     0.515426     0.493099
        5      100.000     0.518673     0.496485     0.514871     0.492542
        6      102.000     0.518117     0.495926     0.514316     0.491985
        7      104.000     0.517562     0.495369     0.513762     0.491428
        8      106.000     0.517007     0.494811     0.513209     0.490873
        9      108.000     0.516453     0.494255     0.512656     0.490317
      10      110.000     0.515899     0.493698     0.512103     0.489762
      11      112.000     0.515346     0.493143     0.511551     0.489209
      12      114.000     0.514793     0.492588     0.511000     0.488655
      13      116.000     0.514241     0.492033     0.510449     0.488102
      14      118.000     0.513690     0.491480     0.509899     0.487550
      15      120.000     0.513139     0.490926     0.509349     0.486998
      16      122.000     0.512588     0.490373     0.508800     0.486446
      17      124.000     0.512038     0.489821     0.508251     0.485895
      18      126.000     0.511489     0.489269     0.507703     0.485344
      19      128.000     0.510940     0.488717     0.507155     0.484795

[gmillward]

[gmillward]

OK, here, for a given longitude slice (in this case mp=73), are the points in the ExB transport q interpolation that have not solved properly and left problematic factors (greater than 1). All below 200km, more towards the equator, and all in the Northern hemisphere:

[timfullerrowell]

Very clear analysis. Good stuff George. I would suggest just making the interpolation consistent with setting Ne,.... Te, Ti values below 90 km equal to the value at 90 km. So it still has make a change. I know it is not as simple as that because it still tries to interpolate in q below 90 km which would have to be suppressed. I don't understand the N/S asymmetry. We assume the south is the same as the north, i.e., we don't even do it in the south. Tim

…

On Tue, May 19, 2020 at 4:07 PM gmillward ***@***.***> wrote: OK, here, for a given longitude slice (in this case mp=73), are the points in the ExB transport q interpolation that have not solved properly and left problematic factors (greater than 1). All below 200km, more towards the equator, and all in the Northern hemisphere: [image: incorrect_q_interp_locations] <https://user-images.githubusercontent.com/24465054/82383270-b49ff400-99ea-11ea-856a-0c47ddb5ce21.png> — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub <#30 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AH5BFOA43PXMZ2EY4WROP53RSL7IDANCNFSM4MUJGS6A> .

[gmillward]

Tim I have a fix and will implement today - I think my fix is what you are saying - if the q interpolation comes from a place below 90km - then it just sets it to 90km - and the interpolation factors are 1.0 (for 90km) and 0.0 (for 92km). The same thing does happen in the south (kinda) - but the way the code is written (looping over q values) - the applicable q interpolation factors are defaults of 1.0 and 0.0 already - so it just so happens that it uses 90km correctly in the South - it's just in the North where the looping 'runs off the end' as it were - and you get huge incorrect interpolation factors (like -30 + 40 etc.). Anyhow, I had the fix implemented and running at the end of yesterday - and running the March 2015 storm where Tzu-Wei saw the NaNs - so just about to check how that went and then hopefully can push the fix up to the develop branch. Incidentally - the way the q-value search is done is very inefficient computationally - I can sort that too, but it's lower priority because my fix will not make any difference in the numbers - just faster [I can explain this over Zoom, hard to write down] Cheers George. On Wed, May 20, 2020 at 9:03 AM timfullerrowell <notifications@github.com> wrote:

…

Very clear analysis. Good stuff George. I would suggest just making the interpolation consistent with setting Ne,.... Te, Ti values below 90 km equal to the value at 90 km. So it still has make a change. I know it is not as simple as that because it still tries to interpolate in q below 90 km which would have to be suppressed. I don't understand the N/S asymmetry. We assume the south is the same as the north, i.e., we don't even do it in the south. Tim On Tue, May 19, 2020 at 4:07 PM gmillward ***@***.***> wrote: > OK, here, for a given longitude slice (in this case mp=73), are the points > in the ExB transport q interpolation that have not solved properly and left > problematic factors (greater than 1). All below 200km, more towards the > equator, and all in the Northern hemisphere: > > [image: incorrect_q_interp_locations] > < https://user-images.githubusercontent.com/24465054/82383270-b49ff400-99ea-11ea-856a-0c47ddb5ce21.png > > > — > You are receiving this because you were assigned. > Reply to this email directly, view it on GitHub > <#30 (comment)>, or > unsubscribe > < https://github.com/notifications/unsubscribe-auth/AH5BFOA43PXMZ2EY4WROP53RSL7IDANCNFSM4MUJGS6A > > . > — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub <#30 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AF2U5HTJX2IT2UGQPZ3Z37DRSPWMPANCNFSM4MUJGS6A> .

-- ---------------------------------------------------------------- Dr. George Millward Cooperative Institute for Research in Environmental Sciences (CIRES) University of Colorado, Boulder Visiting scientist at NOAA Space Weather Prediction Center Boulder, CO george.millward@noaa.gov ----------------------------------------------------------------

[gmillward]

fixed the problem ^^ - now any ExB convection that tracks to points lower than 90km just come from that 90km, which 'should' work fine. Just tested with a 2 day run of the 20150316 storm - no NaNs anywhere so hopeful the results will look good.

[timfullerrowell]

Excellent. Great job George. Tim

…

On Thu, May 21, 2020 at 8:33 AM gmillward ***@***.***> wrote: fixed the problem ^^ - now any ExB convection that tracks to points lower than 90km just come from that 90km, which 'should' work fine. Just tested with a 2 day run of the 20150316 storm - no NaNs anywhere so hopeful the results will look good. — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub <#30 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AH5BFOHLQYWP2OMWFKMQIH3RSU3SPANCNFSM4MUJGS6A> .

[gmillward]

Just need to look at the results - hopefully, all of that 'mess' around 200km and below will now have gone

[twfang]

The 200km problem has been resolved with the latest transport code. See details on PR 34.
NOAA-SWPC/GSMWAM-IPE#34