Tonga eruption shockwave and weather station(s) in Poland

  • Thread starter Thread starter Borek
  • Start date Start date
  • Tags Tags
    Shockwave Weather
AI Thread Summary
The discussion centers on the observation of pressure spikes related to a volcanic eruption, with participants analyzing data from their weather stations across Poland. The eruption occurred at GMT 4:10, and participants noted the arrival of shock waves at their locations, with the first spike observed around 20:05-20:06 local time. The second spike was detected later, but in reverse, prompting questions about the physics behind this phenomenon. The analysis suggests that the shock waves, traveling at approximately 1091 km/h, create transient pressure changes as they propagate. The first wave displaces air in a shrinking circle, leading to a temporary increase in pressure, while the second wave, displacing air in a growing circle, results in a temporary decrease. This interplay of shock wave dynamics and pressure variations is a key focus of the discussion.
Borek
Mentor
Messages
29,132
Reaction score
4,556
Warsaw times, subtract 1 hour for GMT.

It was pointed to me yesterday that we should see these by the same guy that sends helium filled balloons around the world (his latest is in the air for about half a year now), I posted about him some time ago. He posted an image from his weather station yesterday, showing the first spike, so I checked mine - and it was visible as well. Turned out many more people in his bubble have weather stations reporting/registering pressures so there is a bunch of observations from around Poland, probably enough to even do some crude triangulation. We quickly realized that the wave should be visible again several hours later, once it travels around the world in other direction. It was the first thing I checked in the morning - and yes, it is there. But reversed - which I don't get. Any ideas about physics behind? Something happened when the waves converged on the eruption antipodes?

Some input data for analysis if you are interested: eruption time GMT 4:10 (5:10 my time), approximate eruption coordinates: 20.5°S 75.4°W, my coordinates: 52.3°N 21.1°E - around 16200 km. First spike arrived to me at around 20:05-20:06 (I have one minute resolution) and the second one around 2:51-2:52.

obraz_2022-01-16_100321.png


(and if anyone is interested in more plots - comments and discussion are in Polish, but the images are universal ;) )

 
  • Like
  • Informative
Likes Astronuc, 256bits, fresh_42 and 1 other person
Physics news on Phys.org
My thoughts on the change in pressure:

The shock wave is equivalent to suddenly shifting a mass of air forward along a circular front. The transient changes in pressure will be large but will average out. However, as the location is more than half way round the world from the source, the first shock wave will be displacing that air in a shrinking circle, but the second will be displacing that air in a growing circle. So the overall effect will be to temporarily increase the pressure the first time and temporarily decrease it the second.
 
  • Like
Likes russ_watters and 256bits
Just ONCE, I wanted to see a post titled Status Update that was not a blatant, annoying spam post by a new member. So here it is. Today was a good day here in Northern Wisconsin. Fall colors are here, no mosquitos, no deer flies, and mild temperature, so my morning run was unusually nice. Only two meetings today, and both went well. The deer that was road killed just down the road two weeks ago is now fully decomposed, so no more smell. Somebody has a spike buck skull for their...
Thread 'RIP George F. Smoot III (1945-2025)'
https://en.wikipedia.org/wiki/George_Smoot https://physics.berkeley.edu/people/faculty/george-smoot-iii https://apc.u-paris.fr/fr/memory-george-fitzgerald-smoot-iii https://elements.lbl.gov/news/honoring-the-legacy-of-george-smoot/ https://www.nobelprize.org/prizes/physics/2006/smoot/facts/ https://www.aps.org/publications/apsnews/200611/nobel.cfm https://inspirehep.net/authors/988263 Structure in the COBE Differential Microwave Radiometer First-Year Maps (Astrophysical Journal...

Similar threads

Replies
432
Views
52K
Replies
1
Views
10K
Replies
1
Views
3K
Replies
1
Views
3K
Back
Top