26 July: Impressive TID, might it be showing Kelvin Helmholtz Instability?

[Gwyn Griffiths]

1. I saw an impressive TID wave-train signature in the Doppler shift of recently installed WsprSonde transmitter WW0WWV (at WWV) received at WA2TP Long Island on the morning of 26 July. The disturbance spanned ~01:00 to ~07:00 UTC and was seen on other high-stability WsprDaemon receivers across N. America. 
   WsprDaemon Grafana dashboard here shows the record at 10 MHz. Ask me for logon details if you do not have them.
2. Eagerly anticipating the Grape/RX888 records into the PSWS database, I was not disappointed. I suggest this is an event worthy of detailed investigation.
3. For example, the spectrograms from the RX888 Mk II at N8GA show, among other features:

• 10 MHz - a wave train build-up of one-hop Doppler from the F region then a flat-topped  half cycle. If I saw that in the ocean (my professional stomping-ground) I would immediately think of a breaking internal gravity wave and Kelvin Helmholtz Instability. 
• 10 MHz - Part way through the flat-top half cycle two-hop propagation emerges with its higher Doppler. Is there a causal connection? Turbulence or density irregularities?
• 10 MHz - Just before the flat-topped half cycle the E region Doppler shows a step down from its usual near-zero value.
• 15 MHz - Part way through the flat-top cycle at 10 MHz we see, transiently, one-hop  F region propagation as a strong signal against a background of the usual night-time two-hop sidescatter with its lower amplitude and wide spectral width.
• 20 MHz - Step in the E region Doppler from its near-zero value, and very high positive rate-of-change of Doppler on the two-hop sidescatter.
• 25 MHz - Step increase in the signal level of two-hop sidescatter part way through the flat-topped half cycle.

I could go on... What a great data set, and this is only at one of the multitude of Grapes!

This also shows the value of the multiband WsprSonde co-located at WWV as a real-time early-warning instrument of these fascinating space weather events.

Gwyn G3ZIL

[Steve Kaeppler]

Dear Gwyn-

This sounds interesting and I'd be happy to look at my CODAR
observations during this time to see if there was something
interesting or unusual.

All that being said, it would be helpful to see some figures, even if
they are just screen captures.

Thanks,
Steve
AD0AE

> --
> Please follow the HamSCI Community Participation Guidelines at http://hamsci.org/hamsci-community-participation-guidelines.
> ---
> You received this message because you are subscribed to the Google Groups "HamSCI" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to hamsci+un...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/bb140db1-7c26-45de-b3ad-2440e4d9ffd3n%40googlegroups.com.



--

--------------------------------------------------------------------
Steve Kaeppler
steve.k...@gmail.com
cell: 262-707-0932
Amateur Radio Call: AD0AE/6

[HL Serra]

BRAVO ZULU, Gwyn! Well done. This is exactly the type of info I was asking about in the results from the earlier WW0WWV/WA2TP 10MHz data. 

And I liked the oceanographer's observation of the wave results.

Cheers, Larry

--

[David Eckhardt]

Since I'm only some 25 miles from the WWV installation in Wellington, Colorado, (mailing address is out of Fort Collins as Wellington didn't exist when WWV moved to its present site) someone please fill me in on the WSPRsonde frequencies at the Wellington location!  This, especially since NOAA has denied public access to its ionograms and most of what is listed on the Mirrion. 

I do monitor (orthogonal??) scatter from either the WWV 20 or 25 MHz emissions using a DC receiver with a Leo Bodnar for the LO ported to a laptop running Spec Lab.  Dr. Terry Bullett mentions there are too many variables in my monitoring to assume orthogonal bounce.  But I'm looking at only ± 2.5 Hz of the scattered spectrum.   If I configure the setup to monitor CHU on 14.67 MHz, sure, anything but orthogonal scatter.    

Gwyn, for what you just wrote up, I wish we all had a RX888 (or affordable equivalent) supporting at least 5 through 30 MHz with full on-screen spectra and data set.  Could HamSci do a volume buy to reduce the price?

Dave - WØLEV

--

Please follow the HamSCI Community Participation Guidelines at http://hamsci.org/hamsci-community-participation-guidelines.
---
You received this message because you are subscribed to the Google Groups "HamSCI" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hamsci+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/bb140db1-7c26-45de-b3ad-2440e4d9ffd3n%40googlegroups.com.

--

Dave - WØLEV

[Gwyn Griffiths]

Thanks for comments so far.

@Steve - It would be interesting to see if you found unusual propagation events in the CODAR data. I take your point about producing some graphics - I will work on a one-page summary this week.

@Larry - Thank you. Even if it proves to be a red herring, the question finds me reading papers on KHI in the ionosphere, which is proving interesting.

@Dave - Dave Swartz W0DAS installed the WsprSonde at WWV with help from the WWV Radio Club and others. 

The nominal frequencies are as follows. While a Bodnar GPSDO assures long term stability, the frequency synthesis in Paul WB6CXC's WsprSonde means that the precise frequency may not be at a multiple of one Hz. The true frequency on each band will be determined, and will likely be within some 50 milliHz of the following:

(3.570050)
(7.040050)
(10.140150)
(14.097050)
(21.096050)
(28.126050)
These are WSPR transmissions, so will have a ~6 Hz bandwidth.

As for bulk RX888 purchase, I think others in this group are better able to respond. I know it is a topic of discussion on the HamSCI/TAPR Monday 9 PM Eastern Time calls.

thanks all

Gwyn G3ZIL