Relation 10.7 cm Radio Flux and SSN/ Results Formula

[Patrick P.A. Geryl]

 

We published our new formula almost 2 years ago in Astrophysics and Space Science:

https://www.researchgate.net/publication/342766380_A_Formula_for_the_Start_of_a_New_Sunspot_Cycle

Time for an evaluation how good it works:

Results from the fitted adjusted solar flux

 

Date 2020 -2021		Fitted adjusted solar flux from SSN		Adjusted 10.7cm solar flux 20:00	Difference In %
10/2021		88.2		88.3	-0.1
11/2021		86.2		84.4	2.2
12/2021		106.9		99.8	7.1
01/2022		98.3		100.5	-2.2
02/2022		101.9		106.5	-4.3
03/2022		113.7		115.8	-1.8

Edited April 4, 2022 by Patrick P.A. Geryl

[HalfFeralHuman]

So out of curiousity, is there any specific significance to the 10.7cm wavelength, or is it nothing more than coincidence of the equipment available to the people who set the telescope up in the first place? I guess the real question behind this is whether / how this translates to other wavelengths.

[Patrick P.A. Geryl]

Op 4/4/2022 om 15:08, HalfFeralHuman zei:

So out of curiousity, is there any specific significance to the 10.7cm wavelength, or is it nothing more than coincidence of the equipment available to the people who set the telescope up in the first place? I guess the real question behind this is whether / how this translates to other wavelengths.

Direct relationship with the sunspot number. Currently the solar flux stays relatively high despite there are mostly only small sunspots. In Almaty they measure the solar flux on another time then in Canada…

 

You need to activate the link. Program won’t allow link

 

http://89.250.81.98/Solar2010/index_Eng.htm

 

[HalfFeralHuman]

So having summoned up the courage to visit a link behind an IP adress with no associated DNS entry (that's a really bad idea in general), it actually looks legit. So previously it looks like they were measuring both 1Ghz (27.8cm) and 3Ghz (10.7, same as the Canadian one), but seem to have given up on 1Ghz now. Looking back through historical data, there's a fair bit of discrepency between the two wavelengths, so I figure it's reasonable to assume that this correlation with sunspots doesn't transfer over to other wavelengths.

If so, what an extraordinary coincidence! The wavelength 10.7cm was used simply because they happened to reuse old millitary equipment that was the right size for that wavelength. It wasn't a deliberate choice.

Wow! Talk about serendipity!

[Patrick P.A. Geryl]

Op 6/4/2022 om 20:14, HalfFeralHuman zei:

So having summoned up the courage to visit a link behind an IP adress with no associated DNS entry (that's a really bad idea in general), it actually looks legit. So previously it looks like they were measuring both 1Ghz (27.8cm) and 3Ghz (10.7, same as the Canadian one), but seem to have given up on 1Ghz now. Looking back through historical data, there's a fair bit of discrepency between the two wavelengths, so I figure it's reasonable to assume that this correlation with sunspots doesn't transfer over to other wavelengths.

If so, what an extraordinary coincidence! The wavelength 10.7cm was used simply because they happened to reuse old millitary equipment that was the right size for that wavelength. It wasn't a deliberate choice.

Wow! Talk about serendipity!

you are right…
 

Currently the flux is only 100 at Almaty. Sunspot activity in freefall…

[KW2P]

On 4/4/2022 at 9:08 AM, HalfFeralHuman said:

So out of curiousity, is there any specific significance to the 10.7cm wavelength, or is it nothing more than coincidence of the equipment available to the people who set the telescope up in the first place? I guess the real question behind this is whether / how this translates to other wavelengths.

As you might guess, it's the latter, and it's complicated. Radiation at 10.7 cm (2800 MHz) originates in the chromosphere and penetrates Earth's atmosphere so we can measure it on the ground. Long before we could directly measure UV and X-ray radiation by going above the atmosphere, it was discovered that 10.7 cm radio noise correlated remarkably well with sunspot number, so we began measuring it continuously.  The correlation is good from SFI 65 (no sunspots) up to about SFI 110. Above that, the correlation deviates and gets worse the higher it goes.

However, the sun spends a lot of time in the range of SFI 65 to SFI 110 so it's still very useful. It's even more useful because we have accurate measurements of it over several solar cycles. It's still the first-order rule-of-thumb number to watch for radio enthusiasts like myself. You just have to bear in mind that we now know it's a single-number simplification of an extremely complex system.

[Patrick P.A. Geryl]

7 uren geleden, KW2P zei:

As you might guess, it's the latter, and it's complicated. Radiation at 10.7 cm (2800 MHz) originates in the chromosphere and penetrates Earth's atmosphere so we can measure it on the ground. Long before we could directly measure UV and X-ray radiation by going above the atmosphere, it was discovered that 10.7 cm radio noise correlated remarkably well with sunspot number, so we began measuring it continuously.  The correlation is good from SFI 65 (no sunspots) up to about SFI 110. Above that, the correlation deviates and gets worse the higher it goes.

However, the sun spends a lot of time in the range of SFI 65 to SFI 110 so it's still very useful. It's even more useful because we have accurate measurements of it over several solar cycles. It's still the first-order rule-of-thumb number to watch for radio enthusiasts like myself. You just have to bear in mind that we now know it's a single-number simplification of an extremely complex system.

If you read our article, then you will find that high resolution sunspots correlate quite well with the solar flux. In fact a lot better then the ISN… this goes from SFI 64 to more then 200…

(3) (PDF) Calculating the Exact Strength of Solar Cycle 25 using 365 Days Smoothing
https://www.researchgate.net/publication/356556167_Calculating_the_Exact_Strength_of_Solar_Cycle_25_using_365_Days_Smoothing

 

[HalfFeralHuman]

On 4/10/2022 at 10:52 PM, KW2P said:

As you might guess, it's the latter, and it's complicated. Radiation at 10.7 cm (2800 MHz) originates in the chromosphere and penetrates Earth's atmosphere so we can measure it on the ground. Long before we could directly measure UV and X-ray radiation by going above the atmosphere, it was discovered that 10.7 cm radio noise correlated remarkably well with sunspot number, so we began measuring it continuously.  The correlation is good from SFI 65 (no sunspots) up to about SFI 110. Above that, the correlation deviates and gets worse the higher it goes.

However, the sun spends a lot of time in the range of SFI 65 to SFI 110 so it's still very useful. It's even more useful because we have accurate measurements of it over several solar cycles. It's still the first-order rule-of-thumb number to watch for radio enthusiasts like myself. You just have to bear in mind that we now know it's a single-number simplification of an extremely complex system.

This is interesting, and I really like this story. I found this comment on StackExchange too:

Quote

Might be worth mentioning: "It was subsequently established, through both observation and theory, that the best wavelength to observe [the S-]component of solar radio emission is around 10cm. That Covington decided to make observations at 10.7cm wavelength … must count as one of the more significant coincidences in astronomy

 

[Patrick P.A. Geryl]

The highest 10.7 cm solar flux from cycle 24 was measured on October 25, 2014 and reached 219,3.

Several X flares happened around that date.

it is currently 180 and could go higher today because the high resolution sunspot number points to a higher flux number with our formula. Stay tuned.

[Archmonoth]

On 4/10/2022 at 12:52 PM, KW2P said:

...You just have to bear in mind that we now know it's a single-number simplification of an extremely complex system.

 

This resonated with me, and thanks for the little back history of the 10.7cm flux.