How to confirm on any coming geomagnetic storm ?

[oemSpace]

Referring to following image, I would like to know on how to identify Solar sector boundary crossing under WSA-ENLIL Solar Wind Prediction, in order to know on whether solar flare is above / below Heliospheric current sheet.

Furthermore, I would like to confirm on whether following statement is correct or not in order to interpret IMF direction.

If solar flare is above Heliospheric current sheet, then solar flare carry northern IMF
If solar flare is below Heliospheric current sheet, then solar flare carry southern IMF

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

Image

https://1drv.ms/u/s!AuvJV0hx3xTGiGmKQz29x55o1zh7?e=MCmxDs

Referring to following video, it shows on what solar sector boundary crossing is about.

Video:

https://m.youtube.com/watch?v=buV_rHBW7_M

Edited December 6, 2020 by oemSpace

[Vancanneyt Sander]

You can't see a solar sector boundary crossing in Enlil, normally it happens when a CH HSS arrives. The SWPC will mention it in their forecast if it will be happening. As it is always associated with a coronal hole, with each coronal hole there are opportunities for geomagnetic storms and that depends on the size of the coronal hole and what the IMF will do once it arrives at Earth. Once it crosses, the IMF direction will turn the opposite direction.

And now you're mixing solar flares with sector boundary crossings... don't do that. With a CME, as it is much faster than the ambient solar wind, it catches up the solar wind that's in front of it and thus compresses the sheet. This self explaining image says enough. You see the heliospheric sheet that bends around the CME, the CMLE pushes the sheet aside and the cloud of charged particles of the CME moves forward. With CME's the direction of the IMF is always unknown and will fluctuate heavy before it gets stable once the shock has passed. 

Nice example is this storm:

Before the CME arrives, the IMF is slight southward. The CME hits at 14 UTC, the IMF sharply goes northward for an hour and then switches back to south and north and back and forth till 18:00 where it continues to be southward. As with all CME's, this is typical that once it hits, the IMF always fluctuates and in those fluctuations you can have storming for those brief southward moments bit the real storm is in this case later where it went strong southward later that evening producing Kp9.

In this other example we have the opposite happening:

before the CME hit, the field was very calm, the CME hit at 16:00 where the IMF again switches direction in the first hours of the CME arrival with brief moments of southward directed IMF. Later the evening it continued to be northward. In those southward moments the Kp rose to 7- and 8. 

But don't forget that with very strong CME's, if the speed is very high (above 700), geomagnetic storming can still occur with northward directed IMF due to the strength of the CME.

To summarize: you can not predict what the IMF will do with a CME arrival.

[oemSpace]

Would following terms' description be correct?

Before leaving the Sun : Solar flare, a large explosion in the Sun's atmosphere
Leaving the Sun : A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona.
After leaving the Sun : Solar wind, the stream of particles and plasma emanating from the Sun

Do only CME cause solar storm? since CME accompany magnetic field from the solar corona, correct?

Do Solar wind not cause solar storm? since Solar wind not including magnetic field from the solar corona, correct?

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Based on discussion, I need to make clear about each model's assumption as shown below:

under WSA-ENLIL Solar Wind Prediction, it only confirms that Solar wind is coming toward Earth without guarantee IMF direction, that is based on existing CME / solar wind at this moment, correct?

under 27-day Space Weather Outlook, kp-index shows 5 levels on 19 Dec, 2020, since IMF direction cannot be predicated, does this outlook assume that present CME / solar storm is confirmed toward Earth, but IMF direction is based on previous 27-day records in order to forecast and trigger any kp-index alert on 19 Dec, 2020? correct?

https://www.swpc.noaa.gov/products/27-day-outlook-107-cm-radio-flux-and-geomagnetic-indices

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

 

Edited December 6, 2020 by oemSpace

[Vancanneyt Sander]

Did you even read our help section and all answers? Geomagnetic storms can happen from coronal holes and CME’s. That’s it. The only difference between the two is that a coronal hole is a place on the sun where the magnetic field lines are open and the solar wind can escape in space; with CME’s solar plasma is ejected into space due to a solar flare. Enlil will show both types.

27 day forecast shows kp5 for December 19th. As already explained in this topic by Tristan, I won’t repeat it again. The forecast for that day is for a possible coronal hole, but it’s not a certainty as coronal holes can close or evolve. CME’s can’t be predicted upfront as it depends on sunspot regions and their magnetic complexity and their flare activity.

[oemSpace]

On 12/6/2020 at 2:57 AM, Tristan said:

Also I think that the 27 day forecast is based on the previous rotation (please some one correct me if I am wrong). A lot can change in coronal hole and other features from one solar rotation to the next.

Under 27-day Space Weather Outlook, kp-index shows 5 levels on 19 Dec, 2020, since IMF direction cannot be predicated, does this outlook assume that present CME / solar storm is confirmed toward Earth based on previous 27-day's IMF direction in order to forecast and forecast kp-index alert on 19 Dec, 2020? correct?

https://www.swpc.noaa.gov/products/27-day-outlook-107-cm-radio-flux-and-geomagnetic-indices

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

[Vancanneyt Sander]

As we've already explained, the 27-day forecast contains only recurring coronal holes and not CME's as CME's can only be predicted when they occur on the Sun. The 27-day forecast is only updated weekly (and not very accurate) wheras the short term forecast is three days (and more accurate). Only the short term forecast will have predicted Kp for CH and CME. To conclude: dec. 19th is a "possible" arrival of a coronal hole stream.

[oemSpace]

WSA-ENLIL Solar Wind Prediction is updated daily, can WSA-ENLIL be used to predict Kp for CH and CME as well?

There are so many forecast model for solar activity, but I am not clear about their assumption.

For reliable prediction for Kp, I would like to know on following models' assumption.

1) Which model predict Kp for CH only without considering IMF direction?

2) Which model predict Kp for CME only without considering IMF direction?

3) Which model predict Kp for CH only with considering IMF direction?

4) Which model predict Kp for CME only with considering IMF direction?

5) Which top 3 reliable models should be used on monitoring Kp prediction?

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

 

Edited December 7, 2020 by oemSpace

[Vancanneyt Sander]

WSA-Enlil can be used to get an idea of the arrival time of a CH and CME. But it's worth to mention that it is a model and not exact science, so each model (be it of NASA, SWPC or ESA) can give different outcome. And like with many CME's there is an uncertainty factor of + and - 6 hours. Because of the uncertainty factor, this also means that if a CME arrives much later than anticipated, the chances for a geomagnetic storm decrease with time (as a CME decelerates as it travels through space).

To answer the other questions:

1. No model, use short term Kp forecast
2. No model, use short term Kp forecast
3. None
4. None
5. No model, use short term Kp forecast

And if you ask why: because WSA-enlil doesn't give you an idea of the exact strength, it only gives you an indication of the arrival time and an indication of the speed at arrival but with an uncertainty of many hours but it doesn't tell you the strength of the IMF and the possible direction of the IMF as these can't be predicted. So the only thing that is a bit reliable is the short term Kp forecast, but even then it's still a forecast (it can sometimes rain on a predicted sunny day...)

[oemSpace]

WSA-enlil visually show CME coming on 9 Dec, 2020, but max Kp-index is 2 on 9 Dec, 2020 based on following link.  Since IMF direction cannot be predicted, I would like to know on why short term 3-day Kp forecast show sometime high Kp 5 (case 1) and sometime low Kp 2 (case 2) for CH and CME.  Even through CME is visually shown under WSA-enlil for both cases, what make "short term 3-day Kp forecast" different on showing different results for Kp forecast.

N.B. northward IMF direction is not considered as a reason for Kp 2 under this situation, since IMF direction cannot be predicted and keep changing direction.

https://www.swpc.noaa.gov/products/3-day-geomagnetic-forecast

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

 

[Vancanneyt Sander]

Again, current Enlil model does NOT show a CME, it shows the possible arrival of a coronal hole stream. That coronal hole is now positioned in a geoeffective location which means that the increased solar wind of the coronal hole could arrive in about three days. As the coronal hole ain’t that big, SWPC experts have judged that in the forthcoming three days the coronal hole won’t be arriving yet and thus Kp forecast is low. 
Each day, scientists working at the SWPC are making predictions based on the data available and solar observations. Each CME and coronal hole is different so the predictions will always defer depending on each case.

[Tristan]

11 hours ago, oemSpace said:

Under 27-day Space Weather Outlook, kp-index shows 5 levels on 19 Dec, 2020, since IMF direction cannot be predicated, does this outlook assume that present CME / solar storm is confirmed toward Earth based on previous 27-day's IMF direction in order to forecast and forecast kp-index alert on 19 Dec, 2020? correct?

https://www.swpc.noaa.gov/products/27-day-outlook-107-cm-radio-flux-and-geomagnetic-indices

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

The 27 day forecast is just forecasting based on the previous solar rotation. Like I said a lot can change from one rotation to the next. I don't find the 27 day forecast to be very useful for predicting geomagnetic activity. It is more useful to look at features that are visible on the Earth-facing solar disk and use the 3 day forecast, which tends to be more accurate.

Space weather forecasting is a relatively new scientific endeavor and is still in its infancy, and we often finds that it can surprise us. You might find it more useful to understand how to use the various data and instruments work and are used in real time as solar events occur.

For example a long duration C-flare (not particularly strong) is currently ongoing from active region 2790. You can see this in the x-ray data which peaked at C7.4. It is the long duration flares that have a chance of producing CMEs. Short duration or impulsive flares do not produce CMEs. You can then look at SDO 193 A imagery (or better yet video) to see if there is a disturbance to the corona. In this case there is a substantial coronal dimming, which MAY be indicative of a CME eruption. To confirm if a CME has erupted or not, and whether it is Earth-directed, as well as the speed, you then need to look at the C2 and C3 coronagraph imagery. A full-halo CME would indicate a likely Earth-directed CME. SWPC will then run models which can give a better indication of the strength and timing of CME arrival. Type II and type IV radio bursts are also associated with CMEs.

Lets see if we have an Earth-directed CME when coronagraph imagery becomes available. Region 2790 is close to center-disk so IF a CME was launched there is a good chance it would be Earth-directed.

 

Just wondering where I can find the difference imagery I often see posted on this site for the CMEs in both SDO and coronagraph imagery?

 

Edited December 7, 2020 by Tristan

[Vancanneyt Sander]

31 minuten geleden, Tristan zei:

Just wondering where I can find the difference imagery I often see posted on this site for the CMEs in both SDO and coronagraph imagery?

LASCO diffs are available on our SOHO page, for SDO there ain't a way to integrate it in the site, but you can use Solar Demon of the SIDC to look at event based diffs.

[Tristan]

2 hours ago, Vancanneyt Sander said:

LASCO diffs are available on our SOHO page, for SDO there ain't a way to integrate it in the site, but you can use Solar Demon of the SIDC to look at event based diffs.

Thanks:)

 

[oemSpace]

G1 is coming ...

Referring to following link, WSA-ENLIL can tell any unconfirmed coming solar event in advance, but I need to wait for confirmation from 3-day forecast.  When looking at coronagraph imagery instead of data, people need experience to judge on Solar Storm levels, which seems not possible for newbie.

Is there any other models simple and better than WSA-ENLIL & 3-day forecast?

Furthermore, I don't know why update is delayed for 3-day-geomagnetic-forecast. Does anyone know on what different are between 3-day-forecast and 3-day-geomagnetic-forecast on report? which look similar.

Very Good Prediction in advance : https://www.swpc.noaa.gov/products/wsa-enlil-solar-wind-prediction

Good Prediction : https://www.swpc.noaa.gov/products/3-day-forecast

Not Update Yet : https://www.swpc.noaa.gov/products/3-day-geomagnetic-forecast

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

 

Edited December 8, 2020 by oemSpace

[Tristan]

1 hour ago, oemSpace said:

G1 is coming ...

Referring to following link, WSA-ENLIL can tell any unconfirmed coming solar event in advance, but I need to wait for confirmation from 3-day forecast.  When looking at coronagraph imagery instead of data, people need experience to judge on Solar Storm levels, which seems not possible for newbie.

Is there any other models simple and better than WSA-ENLIL & 3-day forecast?

Furthermore, I don't know why update is delayed for 3-day-geomagnetic-forecast. Does anyone know on what different are between 3-day-forecast and 3-day-geomagnetic-forecast on report? which look similar.

Very Good Prediction in advance : https://www.swpc.noaa.gov/products/wsa-enlil-solar-wind-prediction

Good Prediction : https://www.swpc.noaa.gov/products/3-day-forecast

Not Update Yet : https://www.swpc.noaa.gov/products/3-day-geomagnetic-forecast

Do you have any suggestions?
Thanks, to everyone very much for any suggestions (^v^)

 

The 3-day geomagnetic forecast is updated at 2205UCT each day, and hasn't been updated yet. It will be updated later today to show kp5 (G1) conditions for the 9th and 10th. It is always inline with the 3-day forecast.

You will notice that the WSA-ENLIL model has been run in CME mode. This is useful in determining the likely arrival time of the CME (tomorrow evening +/-6 hours.) It is also showing the solar wind speed peaking at over 700Km/s. This last point makes me think that we would likely see kp6 (G2) conditions based on what I have seen in the past (my personal opinion.) Of course this will be highly dependent on the direction of the IMF which can not be forecasted.

It is a similar process with terrestrial weather (if you are into that.) Looking at the models and the satellite imagery and radar, and in this case ground observations. You gradually acquire a better feel for the data. Not that I would claim to be experienced in either space or terrestrial weather.

 

[Christopher S.]

I appreciate the willingness for so many in our community to explain these things in-depth and effectively act as "damage control".

oemSpace seems genuinely curious about many details and has many questions, and you guys have done a good job patiently answering. For anyone who visits this forum for a dose of truth to tamper their anxiety, this is all very interesting and thorough stuff for you to digest.

[oemSpace]

Thanks, to everyone very much for suggestions (^v^)