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Question about the DST Index


MinYoongi

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30 minutes ago, Marcel de Bont said:

You can compare the current month with last month here and here. You can see that since the 29th of June the data has been lower than what it used to be during quiet conditions. There has to be something wrong but the reason behind it is anyone's guess.

DST.PNG

Thanks! Yeah, that's a bit abrupt of a change.

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13 hours ago, Christopher S. said:

Thanks! Yeah, that's a bit abrupt of a change.

Yes, it does seem that "the bottom dropped out" on 2020-Jun-29.  A notable aberration in the current data is the observed DST has been negative for over 2 weeks.

There are examples in the data of such abrupt negative dips (often preceded by a positive bump), such as occurred on 2019-Aug-05.  In that case the DST remained negative for 1 week before the next zero-crossing to positive values:  2019-Aug

 

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Was an interfering magnetic field introduced on 2020-Jun-29?

Did someone at Kyoto take a magnet to work and leave it near the detector?  Were some computers, monitors, or other EMI-generating electrical equipment  introduced or moved?   Were new power distribution lines or networks installed or activated?   Does Comet Neowise have a strong magnetic core that was exposed as it passed the plane of the ecliptic around June 29?

Or did someone accidentally insert a typo of "-25 nT" in the reported DST quicklook formula?

That's a problem with Occam's Razor.  It is a subjective matter of opinion which is the simplest explanation, and "all other factors being equal" is rarely the case.

But if the observed DST reaches a nadir on July 23rd, I say it's Neowise.

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3 hours ago, Drax Spacex said:

Was an interfering magnetic field introduced on 2020-Jun-29?

Did someone at Kyoto take a magnet to work and leave it near the detector?  Were some computers, monitors, or other EMI-generating electrical equipment  introduced or moved?   Were new power distribution lines or networks installed or activated?   Does Comet Neowise have a strong magnetic core that was exposed as it passed the plane of the ecliptic around June 29?

Or did someone accidentally insert a typo of "-25 nT" in the reported DST quicklook formula?

That's a problem with Occam's Razor.  It is a subjective matter of opinion which is the simplest explanation, and "all other factors being equal" is rarely the case.

But if the observed DST reaches a nadir on July 23rd, I say it's Neowise.

Are you upset or something? Did you get kicked off of Reddit, so now you're looking for some sort of confrontation on this humble little website?

I just get the impression that you're mocking me for asking my questions, and thus being an ass for no good reason. If this isn't the case, forgive me for saying so, and please don't take this as an invitation to derail the conversation or begin a flame war.

Edited by Christopher S.
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16 hours ago, Christopher S. said:

Are you upset or something? Did you get kicked off of Reddit, so now you're looking for some sort of confrontation on this humble little website?

I just get the impression that you're mocking me for asking my questions

¿Huh? Where did that come from? :huh:

I didn’t get that impression—I thought he was just continuing a stream of thought he started in his previous reply.

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22 hours ago, Kaimbridge said:

¿Huh? Where did that come from? :huh:

I didn’t get that impression—I thought he was just continuing a stream of thought he started in his previous reply.

Correct!

19 hours ago, Jesterface23 said:

Looking at the plots on the USGS website, Honolulu's data has been down since June 29th. Possibly that messed up automated calculations.

Great observation - yes that could be the indeed be the reason.  The Kyoto web site does show how data from 4 observation sites are combined.  There are supposed to be multiple levels of quality checks, but something perhaps went awry in that process.

If for example a data value of -99 from one site is intended to be a flag that the data is invalid or unavailable, but it is instead used AS-IS and averaged in with the data from the other 3 sites, then you would get a downward offset in the observed DST data of about -25nT.

http://wdc.kugi.kyoto-u.ac.jp/figs/three_versions.jpg

 

Edited by Drax Spacex
removed embedded Kyoto image link - caused page 2 load problem on mobile browser
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Op 16/7/2020 om 03:41, Drax Spacex zei:

Was an interfering magnetic field introduced on 2020-Jun-29?

Did someone at Kyoto take a magnet to work and leave it near the detector?  Were some computers, monitors, or other EMI-generating electrical equipment  introduced or moved?   Were new power distribution lines or networks installed or activated?   Does Comet Neowise have a strong magnetic core that was exposed as it passed the plane of the ecliptic around June 29?

Or did someone accidentally insert a typo of "-25 nT" in the reported DST quicklook formula?

That's a problem with Occam's Razor.  It is a subjective matter of opinion which is the simplest explanation, and "all other factors being equal" is rarely the case.

But if the observed DST reaches a nadir on July 23rd, I say it's Neowise.

You have a lively fantasy that I must admit. 😜👍

Op 16/7/2020 om 07:14, Christopher S. zei:

Are you upset or something? Did you get kicked off of Reddit, so now you're looking for some sort of confrontation on this humble little website?

I just get the impression that you're mocking me for asking my questions, and thus being an ass for no good reason. If this isn't the case, forgive me for saying so, and please don't take this as an invitation to derail the conversation or begin a flame war.

Good you edited your post and apologized. I understand why you got that impression of his post but that was not his intention I am sure of it. 👍

11 uren geleden, Jesterface23 zei:

Looking at the plots on the USGS website, Honolulu's data has been down since June 29th. Possibly that messed up automated calculations.

Great observation! That has to be the reason but strange it has gone unnoticed for so long that is affects the final outcome of the Dst.

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Here's a really good slideshow presentation about the observed DST index calculation.  Delving into the details of how the DST Index is calculated, it is quite a complex procedure.  It is not merely a matter of taking instantaneous magnetometer readings from several observation sites and averaging them.  Far from it!  It's a good read for anyone interested in understanding more detail.  I learned a lot from it - particularly realizing how difficult it could be to identify the root cause of apparently anomalous DST Index data and to track down the component(s) that may be contributing to it.

https://slideplayer.com/slide/4307987/

 

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12 hours ago, Drax Spacex said:

Here's a really good slideshow presentation about the observed DST index calculation.  Delving into the details of how the DST Index is calculated, it is quite a complex procedure.  It is not merely a matter of taking instantaneous magnetometer readings from several observation sites and averaging them.  Far from it!  It's a good read for anyone interested in understanding more detail.  I learned a lot from it - particularly realizing how difficult it could be to identify the root cause of apparently anomalous DST Index data and to track down the component(s) that may be contributing to it.

https://slideplayer.com/slide/4307987/

 

Wow, this is much more in-depth and complex than what I thought went into DST readouts.

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For posterity, the "Honolulu event" occurred on 2020-06-29 22:47:00 UTC.

The Honolulu DST has been negative-shifted since that time.  The Honolulu DST Index was reported as invalid (99999) for a few minutes after the event, but soon resumed reporting DST Index.

Though suspect due to the negative shift, the Honolulu reported DST Index could be presumed to be valid by consumers (e.g. Kyoto).  The Honolulu geomagnetic data has been flagged as invalid (99999) since the event, but the Honolulu DST Index has not.

https://geomag.usgs.gov/plots/dst

https://geomag.usgs.gov/ws/edge/?elements=MDT&endtime=2020-06-29T23:15:00.000Z&format=iaga2002&id=HON&sampling_period=60&starttime=2020-06-29T22:45:00.000Z&type=variation

2020-06-29 22:45:00.000 181 -7.27 88888.00 88888.00 88888.00
2020-06-29 22:46:00.000 181 -7.36 88888.00 88888.00 88888.00
2020-06-29 22:47:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:48:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:49:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:50:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:51:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:52:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 22:53:00.000 181 1288.70 88888.00 88888.00 88888.00
2020-06-29 22:54:00.000 181 -26028.94 88888.00 88888.00 88888.00
2020-06-29 22:55:00.000 181 -27095.66 88888.00 88888.00 88888.00
2020-06-29 22:56:00.000 181 -27038.09 88888.00 88888.00 88888.00
2020-06-29 22:57:00.000 181 -26783.00 88888.00 88888.00 88888.00
2020-06-29 22:58:00.000 181 -26759.66 88888.00 88888.00 88888.00
2020-06-29 22:59:00.000 181 -26759.66 88888.00 88888.00 88888.00
2020-06-29 23:00:00.000 181 -26759.66 88888.00 88888.00 88888.00
2020-06-29 23:01:00.000 181 -26759.67 88888.00 88888.00 88888.00
2020-06-29 23:02:00.000 181 99999.00 88888.00 88888.00 88888.00
2020-06-29 23:03:00.000 181 -101.28 88888.00 88888.00 88888.00
2020-06-29 23:04:00.000 181 -101.22 88888.00 88888.00 88888.00
2020-06-29 23:05:00.000 181 -509.73 88888.00 88888.00 88888.00
2020-06-29 23:06:00.000 181 -101.08 88888.00 88888.00 88888.00
2020-06-29 23:07:00.000 181 -101.01 88888.00 88888.00 88888.00
2020-06-29 23:08:00.000 181 -100.96 88888.00 88888.00 88888.00
2020-06-29 23:09:00.000 181 -100.94 88888.00 88888.00 88888.00
2020-06-29 23:10:00.000 181 -100.76 88888.00 88888.00 88888.00
2020-06-29 23:11:00.000 181 -100.62 88888.00 88888.00 88888.00
2020-06-29 23:12:00.000 181 -100.58 88888.00 88888.00 88888.00
2020-06-29 23:13:00.000 181 -100.57 88888.00 88888.00 88888.00
2020-06-29 23:14:00.000 181 -100.61 88888.00 88888.00 88888.00
2020-06-29 23:15:00.000 181 -100.61 88888.00 88888.00 88888.00

P.S. Whatever consulting fees may be due and payable by USGS etc. to those who have participated in this thread, in consideration for their time, effort, and expertise in the review and analysis of this issue, I suggest should go to the spaceweatherlive general fund.

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  • 1 month later...

No. The Kp-index comes straight from the NOAA SWPC. Whenever they issue an alert for Kp4 or higher we forward it to our app, Twitter account and of course the website. We are seeing some interesting stats at the moment, I am surprised we are occasionally reaching Kp5 but guess it isn't impossible with these numbers. Might be a little bit of the equinox effect coming into play?

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On 8/31/2020 at 7:38 AM, Marcel de Bont said:

No. The Kp-index comes straight from the NOAA SWPC. Whenever they issue an alert for Kp4 or higher we forward it to our app, Twitter account and of course the website. We are seeing some interesting stats at the moment, I am surprised we are occasionally reaching Kp5 but guess it isn't impossible with these numbers. Might be a little bit of the equinox effect coming into play?

Good to hear, thanks! It's pretty cool that a CH is producing as much wind as it is right now. What exactly are you referring to by "equinox effect"?

I've also seen a few mainstream-ish publications/news articles discussing the possibility that our solar system is moving through relatively more dense interstellar media than usual, citing the remnants of stellar explosions long ago. While that is likely ever-present in the ISM, I would be interested to see projects aiming at measuring the density of the ISM outside of the Oort Cloud, but that's likely decades in the future.

Edited by Christopher S.
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4 hours ago, MinYoongi said:

What the f... is Happening now? -157? Im scared :(

It would appear that the magnitude of error has increased over the last month and a half. Not sure why, but it's likely the same root cause as was discussed before. If there was actually conditions like that, it would be reflected in the Kp index and auroral oval product on the main page.

The DST product is not to be trusted, so once it starts looking normal again, we'll let you know. Until then, just ignore it.

Edited by Christopher S.
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  • 1 month later...

I noticed in the past several days that observed and predicted DST's have been aligned pretty well.  I checked the Honolulu (HNL) site, and it's reporting valid data again.  As this is an input to the Kyoto observed DST algorithm, HNL now reporting valid data appears to have fixed the problem.  A longer term fix would be for the Kyoto algorithm to be made more robust to identify bad data sources and exclude them.

Edited by Drax Spacex
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