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MinYoongi

Question about the DST Index

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Good Morning!

Since yesterday the DST Index (Disturbance Storm Time) is really disturbed. It displays almost a moderate storm condition right now, but the KP is only been at 1 or 2 for the last few hours. 

The IMF is relatively low in the minus and nothing looks like its justifying almost -50 in the dst. 

Can you guys maybe explain that phenomenon to me? 

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There appears to be some influence from a coronal hole in the regions of the geomagnetic sensors causing the averaged data to reflect a geomagnetic disturbance, but in reality the influence is weak and isolated to those regions. That's my best guess, based on SWPC forecasting. The only weird thing about it to me is the duration of this isolated disturbance - it's been like this for a bit over 24h, so perhaps the CH wind field is relatively wide. If anyone has light to shed on this, I'd be curious to know as well.

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Thanks alot for your answer Christopher.

So you dont think its anything to worry about? 

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In all honestly it does seem a bit optimistic for the observed DST to be at almost -50nT with the current data. I'd say take it with a grain of salt, my gut feeling isn't trusting the data.

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30 minutes ago, Marcel de Bont said:

In all honestly it does seem a bit optimistic for the observed DST to be at almost -50nT with the current data. I'd say take it with a grain of salt, my gut feeling isn't trusting the data.

Yeah, that is what I thought too.

I just wonder how these Numbers get so jacked up. Is it a model thats been fed wrong data? I've never seen it like that, and even the predicted part is normal.

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This data should be accurate as its observed data so to speak from four magnetometer stations near the equator but I have a hard time believing the data is accurate. But who knows I could be wrong.

Our data comes from the NOAA SWPC but it should correspond with the data found here http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/presentmonth/index.html
The data from Kyoto shows values around -30 to -40 which doesn't correspond exactly with the data from NOAA but considering the numbers are fairly similar it might be correct anyway. Its a tad confusing.

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Can you maybe provide me a Noaa DST link?

Im a bit worried because i dont know where the values are coming from. Hmm. 😕

7 minutes ago, Marcel de Bont said:

This data should be accurate as its observed data so to speak from four magnetometer stations near the equator but I have a hard time believing the data is accurate. But who knows I could be wrong.

Our data comes from the NOAA SWPC but it should correspond with the data found here http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/presentmonth/index.html
The data from Kyoto shows values around -30 to -40 which doesn't correspond exactly with the data from NOAA but considering the numbers are fairly similar it might be correct anyway. Its a tad confusing.

https://www.swpc.noaa.gov/products/geospace-geomagnetic-activity-plot

 

This shows the DST as ~ -10 

What the hell is going on.. 🧐

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28 minuten geleden, MinYoongi zei:

https://www.swpc.noaa.gov/products/geospace-geomagnetic-activity-plot

 

This shows the DST as ~ -10 

What the hell is going on.. 🧐

I'd say that is the prediction which we also have on the site as the black curve. Why the observed values do not match with what can be found on the Kyoto website is something we shall take a deeper look at today as there is something not 100% right.

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I'd love to get an update from you experts later. 

Thank you for this awesome forum and website :) ❤️

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My gut also tells me this data is a bit anomalous. If there is a valid reason for the values to be what they are/were, it would be interesting to look into the cause. But, yes, it just isn't quite right.

For any somewhat superstitious readers/observers out there noticing this, it's not likely a sign of something we should worry about. Seismic activity is not abnormal, GOES data is what you might expect for a quiet period, and the weather is not anymore voracious than it's been for the last few weeks.

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20 uren geleden, MinYoongi zei:

I'd love to get an update from you experts later. 

Thank you for this awesome forum and website :) ❤️

Thanks for the comment. We will dig deeper into the matter as there could be a problem on our end. In the mean time here are the official quicklook Dst data directly from Kyoto. The data there also shows values around -30nT at the moment which I find odd but it is what it is. http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/202007/index.html

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I checked the Kyoto Page a few times, and theyre jacked up too.

On Spoaceweatherlive.com its around -10nt more jacked up though.. But i cant find a source youre getting the data from.

 

This is going on for almost 3 Days now.. Weird :/ While noaa isnt saying anything about it and Solar Wind conditions are really really calm.

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The problem was... We scraped the data from NOAA and stored it on our side. The data was updated afterwards on NOAA's side but not ours that is where the difference came from. We will now check if the data changed from one update to the other so this problem should not occur again. But it does seem they correct the quicklook Dst data all the time.

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15 hours ago, Marcel de Bont said:

The problem was... We scraped the data from NOAA and stored it on our side. The data was updated afterwards on NOAA's side but not ours that is where the difference came from. We will now check if the data changed from one update to the other so this problem should not occur again. But it does seem they correct the quicklook Dst data all the time.

The DST is still a bit odd today. 

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The issue on our end has been solved and checked so the only thing that can be a bit off is SWPC itself 😉 

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Op 4/7/2020 om 02:09, Christopher S. zei:

The DST is still a bit odd today. 

I agree the values remain a bit on the low side but this time the values on our website match those that you can find on here (http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/202007/index.html) so if there is anything wrong with the Dst it is not something we can do anything about it.

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On 7/5/2020 at 1:26 PM, Marcel de Bont said:

I agree the values remain a bit on the low side but this time the values on our website match those that you can find on here (http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/202007/index.html) so if there is anything wrong with the Dst it is not something we can do anything about it.

Agreed, I'm not trying to imply you've made any mistakes. I'm just at a loss for why it has been in this state for as long as it has without correction or at least a statement from SWPC/NOAA. I hope they're not terribly understaffed or underfunded at the moment, lol - it is a bit of a trying time over here in the states.

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Haha no worries I understand you're not implying we made any mistakes. I think the Dst data comes from Japan and the people in charge there might be on vacation or something who knows. I am sure it will be rectified sooner or later.

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I know this thread is mainly a discussion of discrepancies in the observed DST.  But I also have noticed the predicted DST typically seems to have no correlation to observed DST.  Is the predicted DST model really that bad, and is it even useful to show since it differs from observed DST data so egregiously?

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10 hours ago, Drax Spacex said:

I know this thread is mainly a discussion of discrepancies in the observed DST.  But I also have noticed the predicted DST typically seems to have no correlation to observed DST.  Is the predicted DST model really that bad, and is it even useful to show since it differs from observed DST data so egregiously?

The prediction model is generally accurate, but not without its faults. However, the observed DST data is anomalous and doesn't match the actual geomagnetic conditions, so that is why we're concluding that the data from Kyoto isn't to be trusted at the moment. The predicted DST is more in-line with actual conditions, as of the beginning of this anomalous data reporting.

As for how useful it is, well, for now it gives a more accurate picture of the DST than the actual observation data being reported. Generally though, the smaller time intervals of the prediction model make it more useful for Aurora watchers to catch the phenomenon before it's missed.

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11 uren geleden, Drax Spacex zei:

I know this thread is mainly a discussion of discrepancies in the observed DST.  But I also have noticed the predicted DST typically seems to have no correlation to observed DST.  Is the predicted DST model really that bad, and is it even useful to show since it differs from observed DST data so egregiously?

Christopher hits the nail on the head. There is something wrong the observed Dst and it should not be trusted at the moment. The predicted Dst is actually giving us a much more accurate picture at the moment.

During geomagnetic storms there will always be a certain difference between what the model predicts and what the actual Dst records (no model is perfect) but thus far I do not think the difference between the two have been outrageously wrong during storming conditions like the Wing Kp sometimes was. But the Dst is just one of the tools we all have in our toolbox. Don't stare yourself blind on just one graph. Combine all the data we provide to create your own opinion of how the current situation looks like and work with that. 🤘

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12 hours ago, Marcel de Bont said:

Christopher hits the nail on the head. There is something wrong the observed Dst and it should not be trusted at the moment. The predicted Dst is actually giving us a much more accurate picture at the moment.
🤘

Understood.  Thanks for your analysis and deduction / caveat that the observed DST data is currently unreliable.  Periodically sanity-checking the data is a good thing!

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So, while we're on the same page... Do you guys have any guesses as to why it is behaving this way? It is not as though the data is miles off from possible conditions - the trend of data does appear to follow fundamental, empirical patterns... 

What is more likely? An errant, human-based offset applied to data readings?(Imagine the DST is not properly "zeroed"), or, an atmospheric or geological phenomenon influencing the geomagnetic readouts? Is the latter even possible?

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Well, you're only showing 4 hours of data and a couple of points of observed data.  Not enough to characterize as a trend.  But, look back over consecutive data for the past few months.  Crunch the data for each point in time, comparing the slopes and the offset.  There might be a statistical trend observed (or not).  If a trend like a constant offset is found between observed and predicted, then apply Ockham's Razor to make a list the most likely reasons (and throw in a few unlikely reasons as possibilities to also consider for completeness.)

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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

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