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Ionosphere Plasmasphere Electrodynamics Model
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IPE transport revisit #30

Closed twfang closed 4 years ago

twfang commented 4 years ago

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) TEC_default

Modified (no 200km constrain) TEC_no200km

NE at 150km: Default (with 200km constrain) NE150km_default

Modified (no 200km constrain) NE150km_no200km

O+ density at 0316 6UT Default (with 200km constrain) oplus_201303160600_default

Modified (no 200km constrain) oplus_201303160600_no200km

Note that the scales are different in each plot!

O+ velocity at 0316 6UT Default (with 200km constrain) voplus_201303160600_default

Modified (no 200km constrain) voplus_201303160600_no200km

O+ density at 0316 12UT Default (with 200km constrain) oplus_201303161200_default

Modified (no 200km constrain) oplus_201303161200_no200km

O+ velocity at 0316 12UT Default (with 200km constrain) voplus_201303161200_default

Modified (no 200km constrain) voplus_201303161200_no200km

twfang commented 4 years ago

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 commented 4 years ago

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 commented 4 years ago

1 2 3 4 5

gmillward commented 4 years ago

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:

incorrect_q_interp_locations

timfullerrowell commented 4 years ago

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 notifications@github.com 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

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gmillward commented 4 years ago

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

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

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 notifications@github.com 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

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.

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--

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 commented 4 years ago

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 commented 4 years ago

Excellent. Great job George. Tim

On Thu, May 21, 2020 at 8:33 AM gmillward notifications@github.com 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.

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gmillward commented 4 years ago

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

twfang commented 4 years ago

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