Kaimbridge

Discrepancy In X-Ray Data?

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On the Solar activity link for 2017-Jan-16, it lists two B-class flares for the day, a B1.3 @01:44 and a B1.4 @18:23, both of which match SWPCʼs Solar Events page for Jan 16.

However, while if you hover over 01:44 on that dayʼs flare graph, it shows B1.31, when you hover over 18:23, it gives a B1.99, both of which match the values for the time slots on the 1-minute X-ray flux text page for Jan 16!

When you look at the graph, it is obvious that B1.99 is the correct value:  chart-1.jpegWhy the discrepancy?

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Hi @Kaimbridge

Looks like you caught NOAA on a mistake ;). It isn't the first time NOAA classifies flares with faulty strength, we've done multiple corrections in the past for the M1+ solar flares where there was difference in the GOES data and the SWPC logs and those where corrected by us in our databases to make sure we have the correct values. We have now edited the flare so it will display correctly, thx for reporting!

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Thatʼs what I figured.  P=)

On a related note, why do they tend to round flare/flux levels down—e.g., “C3.28” “C3.2”, “X1.79” “X1.7” “X1”—rather than to the nearest (in these examples, it should be “C3.3” and “X1.8” “X2”)?

This doesnʼt seem to be an occasional error, but intended policy:  Is there a valid reason for this?

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It's a good question that we also don't have an answer for. SWPC apparently has an policy to round flares always off to the lower value. In normal math an X1.99 would be X2 but SWPC will always say it was a X1.9. Maybe they do this intentionally to prevent that an M9.97 would be classified as an X1

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17AP26W-SolarImage.thumb.png.8300f7c63f3b0bed1b6866fb48fadff9.png

Is there a reason that the largest flare of the day is maxed as B4.5 at 17:48 (rather than B4.9 or B4.8, as the chart shows it should be at that time?), and not B5.0 or B4.9 at 17:50 as appears to be the case?  Or is this another “NOAA mistake”? 😌  😃

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NOAA often rounds off solar flares like M3.38 as M3.3 but this looks like it's an error of NOAA that marked the peak a bit too early, guess that NOAA had a rough day ;)

PS.: that screenshot looks like our site, but yet the color scheme is different 🤔😃

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23 hours ago, Vancanneyt Sander said:

PS.: that screenshot looks like our site, but yet the color scheme is different 1f914.png1f603.png

Thatʼs because it is your site 😇—I took three screenshots and combined the relevant parts into one concise shot (flipping the bottom line of the 17:50 flare bubble)!  😎

As for the color scheme, yes, I use the inverse white on black. as it is easier on the eyes.  😌

BTW, by including the full flare spectrum up to the unthinkable X100, you eliminated the “Reset Zoom” getting in the way of the flare bubbles!  😍

A suggestion:  Why not add dim colors to the C, B and A chart ranges, too—say, something like light aqua blue (#8FFFFF) for Cs, light lime green (#B0FF50) for Bs and light gray (#D2D2D2) for As—or, at the very least, darken the B and C boundary lines?  😉

 

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Op 2017-4-28 om 05:32, Kaimbridge zei:

Is there a reason that the largest flare of the day is maxed as B4.5 at 17:48 (rather than B4.9 or B4.8, as the chart shows it should be at that time?), and not B5.0 or B4.9 at 17:50 as appears to be the case?  Or is this another “NOAA mistake”? 1f60c.png  1f603.png

I looked at the events file of April 26 and it is not a mistake. The thing is, for some reason they took the peak value as measured by GOES 13 for that event, instead of GOES 15. The X-ray data in the archive is only the data from the primary satellite which is GOES 15 right now. Why they took the data from GOES 13 while GOES 15 was up and running at the time of the event is a mystery for me.

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