New Study Detects Ringing of the Global Atmosphere (phys.org) 24
An anonymous reader quotes a report from Phys.Org: A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study, just published in the Journal of the Atmospheric Sciences by scientists at Kyoto University and the University of Hawai'i at Mnoa, shows that the Earth's entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries. In the case of the atmosphere, the "music" comes not as a sound we could hear, but in the form of large-scale waves of atmospheric pressure spanning the globe and traveling around the equator, some moving east-to-west and others west-to-east. Each of these waves is a resonant vibration of the global atmosphere, analogous to one of the resonant pitches of a bell.
Now in a new study by Takatoshi Sakazaki, an assistant professor at the Kyoto University Graduate School of Science, and Kevin Hamilton, an Emeritus Professor in the Department of Atmospheric Sciences and the International Pacific Research Center at the University of Hawaii at Mnoa, the authors present a detailed analysis of observed atmospheric pressure over the globe every hour for 38 years. The results clearly revealed the presence of dozens of the predicted wave modes. The study focused particularly on waves with periods between 2 hours and 33 hours which travel horizontally through the atmosphere, moving around the globe at great speeds (exceeding 700 miles per hour). This sets up a characteristic "chequerboard" pattern of high and low pressure associated with these waves as they propagate. "For these rapidly moving wave modes, our observed frequencies and global patterns match those theoretically predicted very well," stated lead author Sakazaki. "It is exciting to see the vision of Laplace and other pioneering physicists so completely validated after two centuries."
Now in a new study by Takatoshi Sakazaki, an assistant professor at the Kyoto University Graduate School of Science, and Kevin Hamilton, an Emeritus Professor in the Department of Atmospheric Sciences and the International Pacific Research Center at the University of Hawaii at Mnoa, the authors present a detailed analysis of observed atmospheric pressure over the globe every hour for 38 years. The results clearly revealed the presence of dozens of the predicted wave modes. The study focused particularly on waves with periods between 2 hours and 33 hours which travel horizontally through the atmosphere, moving around the globe at great speeds (exceeding 700 miles per hour). This sets up a characteristic "chequerboard" pattern of high and low pressure associated with these waves as they propagate. "For these rapidly moving wave modes, our observed frequencies and global patterns match those theoretically predicted very well," stated lead author Sakazaki. "It is exciting to see the vision of Laplace and other pioneering physicists so completely validated after two centuries."
Akin to Schumann resonances (Score:3)
These audio resonances are analogous to the electromagnetic resonances of the Schumann resonances [wikipedia.org], first predicted [biodiversitylibrary.org] by G. F. FitzGerald (he of Lorentz-FitzGerald contraction [wikipedia.org] fame) in 1893.
Re: Akin to Schumann resonances (Score:2)
Yeah, just ignore all that pseudoscientific nonsense on YouTube about Schumann resonances, though. People are so dumb. Life in moving fluids is quite amazing, there's no need to get stupid about it.
I've been particularly fascinated by various strands of research that model excitable media such as the BZ reaction, solitons, and relatedpphenomena involving long range propagation through fluids (even the way a fire, or wind, moves through a forest).
Why is anyone surprised? (Score:2, Interesting)
The atmosphere is a fluid and any fluid will have waveforms moving through it when heated by a star and purturbed by a surface. After all , the ocean has global scale waves so why not the atmosphere?
Re: (Score:3)
Re:Why is anyone surprised? (Score:5, Interesting)
I think the point isn't that people are surprised that they exist; the point is that this is the first time the waves have actually been detected in a repeatable way. Now that a successful way of detecting them has been identified (i.e., using the ERA5 dataset), they can be studied systematically. As the authors state in their conclusion, "Notably the amplitudes and widths of the normal mode spectral peaks may contain information on the forcing mechanisms and dissipation for the modes, and the simulation of these properties for each of the many modes we have identified can serve as tests for global climate and weather prediction models."
In addition, the detection of these waves has also led to a confirmation of the value of h, the equivalent depth of the atmosphere. The authors state that their determination of h = 10 km is a confirmation of earlier work, including the famous observation of the pressure pulse from the Krakatau eruption, an event that, of course, could not otherwise be repeated.
Finally, their paper broke new ground, in that:
While the classical solutions for h = 10 km provide the best fit with our observations, we showed there was a small difference between the observed frequencies and the classical predicted frequencies, and that this difference had a systematic dependence on the zonal wavenumber of the mode. This result is suggestive of a small modification of the expectations of classical theory due to a Doppler shift associated with a predominantly eastward mean flow.
It's really a good piece of work.
Re: (Score:2)
This is the coolest thing that I've read all week.
Re: (Score:1)
Re: (Score:2)
Canonical /. Duh! post
Mars has it too, was unexpected! (Score:5, Informative)
Mars has a day or two every year where the whole planets atmosphere rings. Discovered by Viking Landers
It was quite a surprise. The data for this was on tape an not really examined carefully. As it was slowly unspooled from the tapes over one summer circa 1979 (long after the viking landers had expired) a "glitch" in the pressure an temperature record was noted. A similar glitch had been seen in the other lander so maybe just a normal glitch. then after another month of unspooling the tapes, the next martian year was reached in the time series. And surprise another one on the same date.
So it was real. And now it's understood why.
Hess, S. L., J. A. Ryan, J. E. Tillman, R. M. Henry and C. B. Leovy,
The Annual Cycle of Pressure on Mars Measured by the Viking Landers 1 and 2, Geophys. Res. Let., 7, 197, 1980.
Navigation (Score:2)
I wonder how many trillions of animals have been using them every day. "Hey look Jiminy! The monkeys finally noticed the wind!"
Yay, fart jokes! (Score:2)
One small rip for man, one giant ripple for the atmosphere.
Transpose! (Score:2)
Transpose the signal up about...uhhh...22 octaves, and we can listen to it.
Now the most important question (Score:2)
Re: (Score:3, Funny)
Speed of Sound is greater than 700 mph... (Score:1)
What's the frequency, Kenneth? (Score:2)
About 0.0083 Hz or so.
And I thought it was my tinnitus (Score:2)
Comment (Score:2)