Auorora (KP-index) file missing ** Updated **

[bitsostring]

Went back to the drawing board and decided to continue with my NOAA file version because there are problems with the current NOAA file and the current aurora_popup.php script. I will explain in great detail eventually but I’ll start with the basics. Here are the NOAA entries for 15:00 UTC today:

Current {"time_tag":"2021-12-01T15:00:00","kp_index":0}

Mine ["2021-12-01 15:00:00.000","3","3.00","15","8"]

So why is kp zero in one and 3 in the other? I have asked NOAA.

[jaltman]

My sources all show 3 right now. It will be interesting to see what they say. Please share. I expect it will be dropping, the solar wind is up slightly but it is now positively polarized.

Regards,

Jim

[bitsostring]

@jaltman post:42

It will be interesting to see what they say. Please share.

Will do. I expect it’s because the current NOAA file shows kp every minute and it jumps up and down a lot! Kp is meant to be a three-hourly index. . …

Here’s a typical entry:

{"time_tag":"2021-12-01T14:59:00","kp_index":3}

which, according to the current aurora_popup script, is equivalent to an A-index (actually an a-index) of 12:

elseif($kp>=2.9)  { $clr3 = $b_clrs['yellow'];   $txt3 = number_format($kp*4,0);}

Unfortunately we don’t know if the integer Kp-index was actually 2.67, 3.00 or 3.33, which according to the published conversion table should give a-indexes of 12, 15 or 18 respectively.

The file I am using shows Kp every three hours, e.g.

[["time_tag","Kp","Kp_fraction","a_running","station_count"],...["2021-12-01 06:00:00.000","3","3.33","18","8"],["2021-12-01 09:00:00.000","2","2.33","9","8"],["2021-12-01 12:00:00.000","3","3.00","15","8"]]]

where we can see that the two integer Kp-indexes of 3 were actually 3.33 and 3.00, which are shown to have equivalent a-indexes of 18 and 15. So we don’t even need to calculate the a-index, which is good because the current script conditional look-up table does not agree very well with the conversion table.

So it seems to be a choice between a file that is updated regularly but gives only random snapshot integer values every minute; and a file that gives all the necessary three-hourly information but is often updated hours late. . .

[bitsostring]

@bitsostring post:40

I’ve been keeping an eye on these and I notice that the estimated K index is current but the estimated A-index can be for yesterday (or, rather, the last full UT day), e.g.

Solar-terrestrial indices for 26 November follow. Solar flux 92 and [b]estimated[/b] planetary A-index 4. The [b]estimated[/b] planetary K-index at 0900 UTC on 27 November was 1.

I hadn’t realised that there were so many alerts/warnings/forecasts available from NOAA, but I like this one:

:Product: Geomagnetic Forecast :Issued: 2021 Dec 01 2205 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # NOAA Ap Index Forecast [b]Observed[/b] Ap 30 Nov 011 [b]Estimated[/b] Ap 01 Dec 015 Predicted Ap 02 Dec-04 Dec 010-016-012

NOAA Geomagnetic Activity Probabilities 02 Dec-04 Dec
Active 20/35/25
Minor storm 05/25/10
Moderate storm 01/10/05
Strong-Extreme storm 01/01/01

NOAA Kp index forecast 02 Dec - 04 Dec
Dec 02 Dec 03 Dec 04
00-03UT 3 3 3
03-06UT 3 4 3
06-09UT 2 2 3
09-12UT 2 2 2
12-15UT 2 3 2
15-18UT 2 3 3
18-21UT 3 4 3
21-00UT 3 3 3

which shows that the Ap-index is not finalised immediately so we probably shouldn’t even try to calculate it. IMHO the standard popup should just show the K- and a-indices (as now), and I promise not to complain if the a-index is called A (as now)

We just have to decide where we get the K- and a-indices from. . . :?

[pwsdashboard]

@bitsostring post:44

I hadn’t realised that there were so many alerts/warnings/forecasts available from NOAA, but I like this one:

which shows that the Ap-index is not finalised for a couple of days so we shouldn’t even try to calculate it. IMHO the standard popup should just show the K- and a-indices (as now), and I promise not to moan if the a-index is called A (as now)

We just have to decide where we get the K- and a-indices from. . .

You could use the . . ./pwsWD/languages/lang_??.txt

# aurora
 |A-INDEX|A-INDEX|

change that to

# aurora
 |A-INDEX|a-INDEX|

Wim

[bitsostring]

@wvdkuil post:45

You could use the . . ./pwsWD/languages/lang_??.txt

Or lang.en.php, in my case

I have decided to keep both a and an estimate of A on my popup, but I make it clear that it is not the real thing.

And I have made the “Last Updated” time show the time of the last K-index, not the kindex.txt filemtime().

[bitsostring]

Finally got an answer from NOAA about the file at https://services.swpc.noaa.gov/json/planetary_k_index_1m.json:

We publish the 1 minute data for transparency reasons. We are allowing the public access to the data we use to compute our 3-hourly readings. We understand the 3-hourly value is what is most frequently used, but some users also wish to see the "raw" data that goes into our computations. Some have also requested that data be available so they can run their own models and accomplish their own research. Since we are a government agency, the information we use/provide is publicly accessible.

In reply to a supplementary question NOAA confirmed that individual kp-index values from this file should not be used as 3-hourly Kp-indices.