Date
1 - 17 of 17
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@...> To: MSG-1@groups.io Sent: 15/01/2022 13:13:27 Subject: [MSG-1] Huga Tonga
|
||
|
|
||
|
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,
|
||
|
|
||
|
On 16/01/2022 11:16, Ferdinand Valk wrote:
What impressed me most is the propagation of concentric atmospheric shockThanks 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
toggle quoted messageShow quoted text
-----Original Message-----=========================== 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.
toggle quoted messageShow quoted text
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-----===========================
|
||
|
|
||
|
R. Alblas
On 16-01-2022 15:42, R. Alblas wrote:
Time mesasured in Edinburgh: 5:10That must be 18:40, of course...
|
||
|
|
||
|
On 16/01/2022 13:49, Ernst Lobsiger via groups.io wrote:
David,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
|
||
|
|
||
|
On 16/01/2022 14:42, R. Alblas wrote:
I think it's the same shock wave the other way around the world.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
|
||
|
|
||
|
On 16/01/2022 14:42, R. Alblas wrote:
I think it's the same shock wave the other way around the world.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 wasDavid, 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 wasDavid, 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 --
|
||
|
|
||
|
Christian Peters
Nice animation to watch the wave spreading...
toggle quoted messageShow quoted text
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 wasDavid,
|
||
|
|
||
|
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 atmosphericHi 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
|
||
|
|
||
|
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.
|
||
|
|
