I’m caught between sessions but wanted to post this. From a presentation at AGU that I couldn’t attend. This from SciAm:
James Elsner at Florida State University has a killer curve, and lots of caveats. The curve indicates that tornadoes in the U.S. may be getting stronger. The caveats indicate they may not be.
“If I were a betting man I’d say tornadoes are getting stronger,” he noted on Tuesday during a lecture at the annual American Geophysical Union fall meeting in San Francisco.
But when asked directly at a press conference whether that is the case, he would not commit. “I’m not doing this [work] to establish the future intensity of tornadoes,” he explained, but to establish a method that someday could indeed determine if the storms are becoming more powerful.
Because the lecture was titled “Are tornadoes getting stronger?” the audience expected an answer. And their consternation rose when Elsner showed his final graph, adding up the kinetic energy of tornadoes each year from 1994 to 2012.
More here: http://blogs.scientificamerican.com/observations/2013/12/11/tornadoes-may-be-getting-stronger-or-not/
This reminds me of Dr. Ryan Maue’s ACE (accumulated cyclone energy) for hurricanes.
Since measuring tornado wind speed is a hit/miss proposition, even with doppler radar I have many reasons to suspect the data in this graph.
Elsner has 18[years of data]. His data begin in 1994 because that’s when Doppler radar, the best at tracking tornadoes, began covering the entire U.S.
The point of the curve, however, is to show that measuring the length and width of a tornado’s damage path gives an accurate indication of its strength, which is driven by the storm’s peak wind speed. It is difficult if not impossible to measure that speed directly, as is done for hurricanes by ground instruments and planes that fly into the storms.
So, like Mann’s hockey stick, it is a proxy, not the actual measurement.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Some more thoughts here.
http://notalotofpeopleknowthat.wordpress.com/2013/12/13/are-tornadoes-getting-stronger-2/
Try that answer on a science exam: “If I were a betting man I’d say __________________.”
Matthew W. Marler:
“if the method is well-developed and the proxy is accurate enough, he may one day have a technique reliable enough for determining the ongoing changes in annual total tornado strength.”
I should apologize, in advance, as a layman,, for questioning anyone’s comments here( outside alarmist propaganda.), but if I was the student and you were the professor( you might well be!), I would have some serious questions about your analogies to temperature measurement by proxy and any method, however sophisticated, that could be devised to measure tornado energy in a year.. How would you ever get accurate data, based on the living, breathing, chaotic nature of tornadoes, to develop correlations to begin with, and, second, how would you ever accurately apply such information, given the same problems?
(1)You would need orders of magnitudes more doppler radar trucks manned by folks like Dr. Howie Bluestein and his students at the University of Oklahoma, deployed at close range
to tornadoes.getting cross sections from the ground up.
(2) Other data could be collected, I suppose, by hundreds of “Dominators” manned by an equal number of Reed Timmers and associates, measuring vertical velocities from inside twisters and sending probes into them?
(3) How would you get accurate data over the length of the storm? It’s hard enough to make a close approach at one point in time and space. That’s why they call them storm “chasers”.
(4)We haven’t, finally, discussed the finances needed to back research on such scales totally dwarfing Project Vortex.from years gone by. You’d need a large enough sample size to make the various correlation coefficients and equations significant would you not?
Perhaps the student is missing something, asking the wrong questions, or displaying a level of ignorance to the process. Thank you for humoring me.