Hunga Tonga


Ferdinand Valk
 

And one remapped version of Hunga Tonga’s eruption

 

From: MSG-1@groups.io On Behalf Of Philip Robinson
Sent: Saturday, 15 January, 2022 15:22
To: MSG-1@groups.io
Subject: Re: [MSG-1] Huga Tonga

 

Hi

One final image

regards

Philip

 

------ Original Message ------

From: "Ernst Lobsiger via groups.io" <ernst.lobsiger@...>

Sent: 15/01/2022 13:13:27

Subject: [MSG-1] Huga Tonga

 

Hi All,

This volcano eruption can now be observed with Himawari-8 and GOES-17.
Point your software to latitude -20.57 (South) and longitude -175.38 (West).

Cheers,
Ernst

 

Virus-free. www.avg.com


Ernst Lobsiger
 

Hi Ferdinand,

thank you for correcting my typo. Here is some Japanese ash ...

Cheers,
Ernst


Ernst Lobsiger
 

Hi,

there is also a fine Metop-C pass showing the aftermath of this "Hunga Tonga" explosion.
Yes, it's "Hunga" not "Huga". Glad I didn't type "Hugo Tango" in the heat of discovery :-) ...

Cheers,
Ernst


Ferdinand Valk
 

What impressed me most is the propagation of concentric atmospheric shock waves, that registered barometrically all the way in New Zealand!

 

I posted an animation here http://fvalk.com/Of-Interest.htm

 

 

From: MSG-1@groups.io On Behalf Of Ernst Lobsiger via groups.io
Sent: Sunday, 16 January, 2022 09:48
To: MSG-1@groups.io
Subject: Re: [MSG-1] Hunga Tonga

 

Hi,

there is also a fine Metop-C pass showing the aftermath of this "Hunga Tonga" explosion.
Yes, it's "Hunga" not "Huga". Glad I didn't type "Hugo Tango" in the heat of discovery :-) ...

Cheers,
Ernst


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On 16/01/2022 11:16, Ferdinand Valk wrote:
What impressed me most is the propagation of concentric atmospheric shock
waves, that registered barometrically all the way in New Zealand!

I posted an animation here http://fvalk.com/Of-Interest.htm
<http://fvalk.com/Of-Interest.htm>
Thanks for the animations, Ferdinand.

Indeed the shock-waves have propagated around the world, being received here on
my barometers twice so far, once on the short path, and once on the long path.
Now wondering whether there might be a third or fourth occurrence.

This has been widely discussed on Twitter - here's my post:

https://twitter.com/gm8arv/status/1482613715837009920

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Ferdinand Valk
 

-----Original Message-----
From: MSG-1@groups.io On Behalf Of David J Taylor
GM8ARV ?????????????? ???? via groups.io
Sent: Sunday, 16 January, 2022 13:11
To: MSG-1@groups.io
Subject: Re: [MSG-1] Hunga Tonga

On 16/01/2022 11:16, Ferdinand Valk wrote:
What impressed me most is the propagation of concentric atmospheric
shock waves, that registered barometrically all the way in New Zealand!

I posted an animation here http://fvalk.com/Of-Interest.htm
<http://fvalk.com/Of-Interest.htm>
Thanks for the animations, Ferdinand.

Indeed the shock-waves have propagated around the world, being received
here on my barometers twice so far, once on the short path, and once on the
long path.
Now wondering whether there might be a third or fourth occurrence.

This has been widely discussed on Twitter - here's my post:

https://twitter.com/gm8arv/status/1482613715837009920

Cheers,
David
===========================

Thanks David. Your graph shows it perfectly well and seeing it twice at your location from the other side of the globe is something else indeed. What struck me especially is that one can actually SEE the blast ring propagating away from the volcano in three successive waves, giving a sense of speed and magnitude of the wave.

Cheers,
Ferdinand


Ernst Lobsiger
 

David,

TBH I have no idea about this cadget. But I wonder is something has even been detected with Raspberry Shake (?).

Regards,
Ernst


R. Alblas
 

I think it's the same shock wave the other way around the world.

Distance from Tonga to Edinburgh: 16000km straight, so 24000km the other way around.

Speed of sound: 343m/s=1230 km/h.

Time start eruption: 5:10 (from Ernst's  picture created by Satpy)
Time mesasured in Edinburgh: 5:10 and 2:00 (next day)
Travel time: 13.5 and 21 hours.

Using speed of sound:

in 13,5 hours: 16000 km is travelled.
In 21 hours: 25800 km.

Close enough, I think, to prove that's the same thing you measured.

Rob.

On 16-01-2022 14:39, Ferdinand Valk wrote:
-----Original Message-----
From: MSG-1@groups.io On Behalf Of David J Taylor
GM8ARV ?????????????? ???? via groups.io
Sent: Sunday, 16 January, 2022 13:11
To: MSG-1@groups.io
Subject: Re: [MSG-1] Hunga Tonga

On 16/01/2022 11:16, Ferdinand Valk wrote:
What impressed me most is the propagation of concentric atmospheric
shock waves, that registered barometrically all the way in New Zealand!

I posted an animation here http://fvalk.com/Of-Interest.htm
<http://fvalk.com/Of-Interest.htm>
Thanks for the animations, Ferdinand.

Indeed the shock-waves have propagated around the world, being received
here on my barometers twice so far, once on the short path, and once on the
long path.
Now wondering whether there might be a third or fourth occurrence.

This has been widely discussed on Twitter - here's my post:

https://twitter.com/gm8arv/status/1482613715837009920

Cheers,
David
===========================

Thanks David. Your graph shows it perfectly well and seeing it twice at your location from the other side of the globe is something else indeed. What struck me especially is that one can actually SEE the blast ring propagating away from the volcano in three successive waves, giving a sense of speed and magnitude of the wave.

Cheers,
Ferdinand






R. Alblas
 

On 16-01-2022 15:42, R. Alblas wrote:
Time mesasured in Edinburgh: 5:10
That must be 18:40, of course...


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On 16/01/2022 13:49, Ernst Lobsiger via groups.io wrote:
David,

TBH I have no idea about this cadget. But I wonder is something has even been
detected with Raspberry Shake (?).

Regards,
Ernst
Ernst,

The readings are collected by a Windows PC, and by three Raspberry Pi cards.
The sensors are consumer-level BME280 chips and similar.

https://learn.pimoroni.com/article/getting-started-with-bme680-breakout

I didn't see anything on my RaspberryShake in Edinburgh, but those nearer and
with lower noise levels did.

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On 16/01/2022 14:42, R. Alblas wrote:
I think it's the same shock wave the other way around the world.

Distance from Tonga to Edinburgh: 16000km straight, so 24000km the other
way around.

Speed of sound: 343m/s=1230 km/h.

Time start eruption: 5:10 (from Ernst's  picture created by Satpy)
Time mesasured in Edinburgh: 5:10 and 2:00 (next day)
Travel time: 13.5 and 21 hours.

Using speed of sound:

in 13,5 hours: 16000 km is travelled.
In 21 hours: 25800 km.

Close enough, I think, to prove that's the same thing you measured.

Rob.
Thanks, Rob. Yes, it's been widely discussed on Twitter, and is well known in
Amateur Radio circles as short-path and long-path propagation.

There's a really interesting plot here showing propagation across the UK for
both shock-waves:

https://twitter.com/imthursty/status/1482816524490579971

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On 16/01/2022 14:42, R. Alblas wrote:
I think it's the same shock wave the other way around the world.

Distance from Tonga to Edinburgh: 16000km straight, so 24000km the other
way around.

Speed of sound: 343m/s=1230 km/h.

Time start eruption: 5:10 (from Ernst's  picture created by Satpy)
Time mesasured in Edinburgh: 5:10 and 2:00 (next day)
Travel time: 13.5 and 21 hours.

Using speed of sound:

in 13,5 hours: 16000 km is travelled.
In 21 hours: 25800 km.

Close enough, I think, to prove that's the same thing you measured.

Rob.
I meant to add, Rob, that the number fit well. What I had wondered about was
what speed of sound to use, as I think it will vary with height. Put another
way round - can we tell the height of the pressure wave by the speed at which
it travelled?

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Ernst Lobsiger
 

On Sun, Jan 16, 2022 at 11:00 PM, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 wrote:
What I had wondered about was
what speed of sound to use, as I think it will vary with height.
David,

the speed of sound in air basically varies proportional to the square root of absolute temperature Ta. For Ta=293.15K which is Theta=20°C the speed is c=343 m/s.
There is a widely used linear approximation for temperatures Theta -20°C to +40°C   c = (331.5 + 0.6 * Theta), Theta = Temperature in °C. This shows not dramatic
change with height but clearly the "ground" wave will be the fastest. There might also be reflections of the originally spherical wave at the tropopause as the stratosphere
shows again increasing temperature with height (inversion). This is similar to short waves being reflected at high "electric" layers in the atmosphere at night.

That said I'd expect a relatively sharp rise of the pressure and then some bouncing up and down behind. That's what your first plot seems to show for Edinburg.
On several movies of the eruption we can see at least two shock waves. This might show two explosions or a reflection. As usual nature is more complicated ..

Regards,
Ernst


R. Alblas
 

I meant to add, Rob, that the number fit well.  What I had wondered about was
what speed of sound to use, as I think it will vary with height. Put another
way round - can we tell the height of the pressure wave by the speed at which
it travelled?

Cheers,
David
David,

The tome of the direct wave fits very well, but that's more of a coincidence, I think. Speed of sound changes with air temperature, humidity and more. I did just pick an average number.

If the wave would travel at 1 km height that would mean just 6 km more travel distance, which is just 17 seconds more traveling around the world.

A change in travel speed does do much more: 331 m/s at 0 degrees, low humidity, average is 343; that changes travel time 30 minutes from Tonga to Edinburgh.

(Just pick up some numbers from Wikipedia etc., I am not a "sound speed expert"  ;-) )

It would be interesting to see more graphs around the world, especially from Africa, where the 2 waves did meet each other...


Rob


--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv




Christian Peters
 

Nice animation to watch the wave spreading...

https://twitter.com/MathewABarlow/status/1482773777410891779?s=20

Regards,

Christian

Am 17.01.22 um 09:56 schrieb R. Alblas:


I meant to add, Rob, that the number fit well.  What I had wondered about was
what speed of sound to use, as I think it will vary with height. Put another
way round - can we tell the height of the pressure wave by the speed at which
it travelled?

Cheers,
David
David,

The tome of the direct wave fits very well, but that's more of a coincidence, I think. Speed of sound changes with air temperature, humidity and more. I did just pick an average number.

If the wave would travel at 1 km height that would mean just 6 km more travel distance, which is just 17 seconds more traveling around the world.

A change in travel speed does do much more: 331 m/s at 0 degrees, low humidity, average is 343; that changes travel time 30 minutes from Tonga to Edinburgh.

(Just pick up some numbers from Wikipedia etc., I am not a "sound speed expert"  ;-) )

It would be interesting to see more graphs around the world, especially from Africa, where the 2 waves did meet each other...


Rob


--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv







Ulrich G. Kliegis
 

Von: "Ferdinand Valk" <fvalk@fvalk.com>
An: <MSG-1@groups.io>
Betreff: Re: [MSG-1] Hunga Tonga
Datum: Sun, 16 Jan 2022 11:16:31 -0000
Antwort an: <MSG-1@groups.io>

What impressed me most is the propagation of concentric atmospheric
shock waves,
Hi folks,

What do we see here actually - do the shock waves effect a kind of ripple on the
atmosphere's surface, changing the refraction properties of the layers, like a
ring-shaped lens, or does the density change lead to a change in transparency
(transmission) properties ? Or both? Or a momentary change of humidity
condensation and vaporization?

Probably not that easy to repeat this experiment... :)

Cheers,

Ulli


Ulrich G. Kliegis
 

Betreff: Re: [MSG-1] Hunga Tonga
An: <MSG-1@groups.io>
Von: "Ernst Lobsiger via groups.io"
<ernst.lobsiger=belponline.ch@groups.io>
Datum: Sun, 16 Jan 2022 01:48:26 -0800
Antwort an: <MSG-1@groups.io>

Glad I didn't type "Hugo Tango" in the heat of discovery :-) ...
The Huge Hugo Tango Bang.

SCNR.

Cheers,
U.