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.
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What happened to the 1970’s?
Looks like a one-year spike.
From NOAA’s On LIne Tornado FAQ page:
What was the biggest known tornado? On 31 May 2013, a deadly, multiple-vortex tornado near El Reno, OK carved a maximum path width of 2.6 miles (from preliminary data). That width barely exceeded that of the Hallam, Nebraska F4 tornado of 22 May 2004. Two and a half miles probably is close to the maximum size for tornadoes; but it is quite possible that others this size or somewhat larger have occurred that weren’t sampled by high-resolution radars or surveyed so carefully in the field.
http://www.spc.noaa.gov/faq/tornado/index.html#Climatology
Rather says it all.
More junk science from Elsner.
Meanwhile, EF3+ tornadoes have clearly declined since the 1950-70’s.
http://www1.ncdc.noaa.gov/pub/data/cmb/images/tornado/clim/EF3-EF5.png
These people are more and more displaying characteristics with the insane guy on the street holding up his sign – The end of the world is nigh – repent!
Bullshit. Tornado intensity scale is logarithmic, therefore annual integrated kinetic energy is dominated by the strongest ones. Now, there were almost twice as many F5/EF5 tornadoes in the first half of the epoch since 1950 than in the second one.
If it is not definitive, then the data must be bogus.
Strikes me he is trying to have it both ways: make a claim that isn’t a claim, so he can’t have to produce data to back it up, but have a useful graphic added to the toolbox of CAGW supporters.
It looks like another model, one of his imagination or “in principle”, something he would claim we should see with CAGW …. but haven’t yet, but will be “observations” to the unsuspecting.
More gaming the system.
Lots of talk about this topic based on Richard Muller’s “The Truth About Tornadoes,” Op-Ed article asserting there was a measurable decline in strong tornadoes over at Dot Earth.
http://dotearth.blogs.nytimes.com/2013/12/09/a-closer-look-at-tornadoes-and-global-warming/
A raft of experts rebutted Muller here: http://www.livescience.com/41632-the-truth-about-tornadoes.html
and have filled in some details for Revkin as a follow up.
Paul Markowski and Harold Brooks have been participating in the comments section.
[Spoiler Alert]
Bottom line — there is not enough data to prove no decrease…but much stronger case can be made for there not being an increase.
My goodness, does Elsner think that we are all idiots? If the proxy is the size of the “swath path” then this metric can only be used when the twister rips through a community where the damage path can be accurately measured and the media interest is high.
Most tornados hop across open farmland where the so called “swath path” is very difficult to measure and often is not. No one cares much about a long lived F5 that ruffles up a recently harvested open farm field. The measurements he is using are skewed by the probability of how many tornados actually hit populated areas. Recently there has a rash of these striking populated areas mainly because of urban sprawl.
When and if accurate direct wind speeds are made on a large sample of tornados in all areas over a long period of time, a more meaningful metric in the meantime is how many tornados form every year. So far this simple metric shows a down turn in the quantity in spite of the fact that more eyes are on the skies now than in the past.
This silly paper is just one baby step above using divining rods, basically warmist pseudo-science masquerading as science.
(fyi — link to scientific American article didn’t work as of a few minutes ago)
Okay. Just for the fun of it, Mr. Eisner, let’s (just for grins) say that tornadoes are increasing in intensity. So what?
You have proven exactly: nothing.
Facts be damned, Elsner knows the take away ‘impact ‘ is in the image and he also knows that which comes at the end is best remembered. Grant seeking science by PR in action.
How long this enters the dogma of ‘the cause ; and we it held up as ‘proof’ of AGW ?
Have a look at NOAA United Stated Annual Trend of LSR Tornadoes, A plot of the annual running total of U.S. tornadoes.
http://www.spc.noaa.gov/wcm/torngraph-big.png
Sorry — ELsner (I know some Eisners, never heard of “Elsner” — likely very few others have either, bwah, ha, ha, ha, haaa)
Alberta Clipper before Christmas?
http://www.hpc.ncep.noaa.gov/pwpf/wwd_accum_probs.php?fpd=24&ptype=snow&amt=1&day=3&ftype=probabilities
In all this REMEMBER that RADAR does not measure the speed of ‘air’ movement directly (although frontal activity can often be seen at the juncture of two differing airmasses), but rather any debris, rain, hail or other aqueous meteors (Hydrometeors) which may be present.
Also, be aware that there are various algorithms running on the various data processing platforms involved in the processing of Doppler imagery as detected by the WSR-88D network … some of these algos have gotten ‘revisited’ over the years as the various digital processing systems have been upgraded in the WSR-88D ‘hardware chain’ to ‘COTS’ (Commercial Off the Shelf) processors rather than the specialized hardware originally fielded back in the late in the 90’s.
“The first installation of a WSR-88D for operational use in everyday forecasts was in Sterling, Virginia on June 12, 1992. The last system of this installation campaign was installed in North Webster, Indiana on August 30, 1997”
.
One minor little detail there, prior to doppler radar, and the development of the EF ratings, tornadoes were only rated based on ,b>observed damage to structures. The strongest tornadoes went unrated if they did not manage to hit a building to allow them to be rated, and then you only got a brief snapshot of the damage potential at that moment when the storm impacted the structure. Ripping up fences, trashing cars and slam dunking cattle did not provide any rating information even though the storm winds might have been well into the F5 range.
A friend of mine (storm chaser) was investigating a very powerful tornado that struck in the extreme northeast part of Colorado and South Western Nebraska years ago. It was officially unrated, but its winds sucked the pavement up off of roadways and shredded cars, breaking them up so badly, that durable components like engine blocks were stripped of their accessories like intake manifolds, and transmissions broken off the engine. While trying to reconstruct the damage track, he talked to a farmer who was trying to find a big enough piece of his farm equipment to prove to the insurance company it had been destroyed by the tornado. It was probably a high 200 mph wind speed tornado due to incidental damage reports he discovered during his investigation, but it missed all structures and was never rated by the National Weather Service.
As a result the reports earlier than the wide spread use of doppler and the EF rating system will be significantly biased low on reports of the strongest tornadoes. This is a strong built in hockey stick bias to the analysis.
Key words here:
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.
. . . “began”
It took a good part of the 1990’s to install the entire network. The system designers and the Install crews had their work cut out for them, from site selection, site acquisition, preparation (grading, electric power, the ‘laying’ telco T1 “T-span lines” for data-backhaul to the various NWS field/forecast offices), tower and building construction, transmitter and processing equipment installation and commissioning at both the RADAR site and local field offices. Then came the training of the NWS personnel for operational use …
This was a big project.
.
They just really really need for them to be getting stronger, because it helps sell the CAGW sky-is-falling-we’re all-gonna-die cause. Especially since the warming has stopped for some 17 years, and people are starting to notice.
We aren’t going to totally ignore the WSR-57 and WSR-74 RADARs that covered the eastern (basically, east of the Rockies) US, are we?
RADAR ops were ‘trained’ to look for specific features on ‘returns’ (hook echo anyone?) in these days too. I recall in the mid 1970’s onward Storm spotters here in the Dallas/Ft. Worth area depended on the RADAR operators in Stephenville (SW of Ft. Worth) as well as the several TV stations (such as CH 5 and Harold Taft) for ‘heads up’ from the RADAR perspective …
.
Chart looks like the increase in doplar radar sites.
I suspect the data point for 2013 will be about the same or less than 2012. This presentation is one of the finer cherries I have seen picked. The historic F3/5 graph show this clearly. Not including this graph in the presentation for context speaks loudly regarding its level of credibility.
Has the process of peer review changed?
If it has then I want to say:
Is James Elsner funded by an insurance company or does he have shares in any insurance company?
PS I don’t have any fossil fuel interests whatsoever – except I use them.
Looks like another hockey stick. More breaking news on break wind.
_Jim says:
December 11, 2013 at 3:57 pm
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Even worse, the tail-end “charlies”.
It is not so much the line of storms sometimes, it’s the independent super-cells that need watching.
Thus the radar.
Aside from all of the standard issues: comparing apples and oranges, only starting at a time when more sensitive instruments are coming online, inconsistent error bars, etc. – the trend is defined by a few years. Weak data, weak conclusions.