Can we prevent tornadoes?

DaveC426913

Again (and possibly for the last time), you cannot simply state this because you think it is plausible.

Prove it.

[EDIT Oh. Evo beat me to it.]

Evo

I never made any claims about tornadoes gaining strength from water.

DaveC426913

In refuting artist's claim that dumping water into a tornado would weaken it, you pointed out that "...tornadoes form from severe rain storms and hurricanes...". While you didn't say explicitly that tornadoes get strength from moisture, it seemed to be the implication - the significance of the comment - to this reader (and thus possibly others). So I went to see if I could bolster the notion (after all that is how hurricanes get their power). But I haven't been able to find a reference either way.

Dotini

http://abcnews.go.com/WNT/video/torn...river-13737392

Here is a video, taken on cue for you just minutes ago, of a tornado crossing a major river at Springfield, Mass.

Respectfully submitted,
Steve

Evo

Just remember, if I don't say something, it's because I didn't say it, for a reason. So please refrain from guessing what I might have said or might have meant. You can always ask "did you mean to say *this* and forget?, and I'll say *no*.

But that doesn't mean that these conditions always create tornadoes. All I asked was for him to back up what he said. He refused.

http://www.nssl.noaa.gov/edu/safety/tornadoguide.html

Since he's reading the global rules now. Here's the earth forum rules for artist.

Evo

Wow, amazing.

cph

Might larger cities statistically be more protected because of a heat shield effect? Perhaps the heat of a city is distruptive, in that if more heat (energy) is added to the atmosphere, then perhaps less exothermic water droplet formation.

Ophiolite

This 2010 paper appears to contradict artists claim. The detailed maths are rather dense, but if I am interpreting it correctly, water would enhance rather than detract from the energy of the tornado.

Dotini

http://www.rawstory.com/rawreplay/20...funnel-clouds/

This is excellent video of the business-end of a Springfield 6/1/11 tornadic vortex just as it attaches itself to the surface. Without this critical leech-like attachment, tornadoes would be only a minor nuisance. Wouldn't learning how to prevent, reverse or destroy this one feature solve our problem?

Respectfully submitted,
Steve

Evo

I've actually read that more heat causes more tornadoes, but this was in a discussion of AGW, so you will need to do your own research on that.

Here is a reason we do not see many tornadoes in a major downtown area.

http://www.spc.noaa.gov/faq/tornado/

Evo

Although this from the two tornado links I posted previously.

http://www.nssl.noaa.gov/faq/faq_tor.php

Dotini

I was unable to locate the statement regarding "tornadoes being formed and sustained by purely thermodynamic processes" in the NOAA FAQ. Perhaps it has been deleted?

Anyway, I thought readers, particularly Chas Chandler, would be intrigued by this:

http://www.jstor.org/pss/1723338

Electric Currents Accompanying Tornado Activity

Abstract
Measurements of the magnetic field and earth current in the vicinity of a tornado show large step-like deflections coincident with the touching down of the funnel. Calculations with a simple current model indicate that a minimum current of several hundred amperes must be postulated to account for the observed deflection in magnetic field. The existence of a steady current of 225 amperes for a period of about 10 minutes provides joule heat at the rate of approximately 10$^{10}$ joules per second, and involves a total charge transfer of 135,000 coulombs. The calculations imply that a tornado is electrically equivalent to several hundred isolated thunderstorm cells active simultaneously.

Respectfully submitted,
Steve

ChasChandler

Hey Steve,
I have never seen any evidence of there being more than one mesocyclone (the large, rotating updraft) inside a supercell. The mesocyclone typically has a diameter of something like 2 km, which is the diameter of a very large tornado. While there can be tornadoes anywhere in the vicinity (sometimes several km away), to my knowledge the main tornado is always associated with the mesocyclone.

Here are some rough calculations that I did, using numbers from the source that Steve quoted, as well as other sources. Tornadoes do seem to get a respectable amount of energy from the release of latent heat from the condensation of water vapor, while ohmic heating from the electric current inside the tornado appears to make a far more substantial contribution.

First the latent heat calculations. Let's assume that the ambient temperature is a sweltering 40 °C, and that the relative humidity is 100%. The lowest pressure drop ever recorded in a tornado was 100 mb below ambient. That would lower the temperature to roughly 10 °C, forcing the condensation of most of the water vapor, and the release of latent heat.

maximum water vapor content at 40 °C = 51.1 g/m³

maximum water vapor content at 10 °C = 9.4 g/m³

condensation = 51.1 − 9.4 = 41.7 g/m³

tornadic inflow (EF1) = 1,000 m³/s

total condensation = 1,000 m³/s × 41.7 g/m³ = 41,700 g/s

latent heat from condensation of water = 2,257 J/g

total latent heat = 41,700 g/s × 2,257 J/g = 94,117,000 J/s

watt = joule / second

power = 94,117,000 W

Now the ohmic heating calculations. The magnetic field generated by a tornado was measured at 1.5 × 10⁻⁸ teslas from a distance of 9.6 km away using a magnetometer. From this we can calculate the amps.

amps = teslas × 2 π r / permeability

permeability of air = 4 π × 10⁻⁷ N/A²

amps = (1.5 × 10⁻⁸ × 2 × 3.14 × 9600) / (4 × 3.14 × 10⁻⁷) = 720 A

Guessing that the tornado was 300 m tall, and given an electric field of 5 kV/m, we can then calculate the watts.

volts = 300 m × 5,000 V/m = 1,500,000 V

watts = amps × volts = 720 × 1,500,000 = 1,080,000,000 W

More conservative estimates of the typical current densities are in the range of 100~250 amps, but even at the resultant 150~375 million watts, that's still a lot more power than the 100 million watts that could be coming from latent heating.

In addition to the ohmic and the latent heating inside the tornado, there is also, of course, the low pressure aloft inside the thunderstorm enhancing the updraft, and there is also frictional heating at the lower boundary.

Only the frictional heating at the ground level could possibly be responsible for the extreme low pressure at the base of the tornado, as it is the only energy source that is concentrated near the ground. Estimates of the (destructive) work done by the tornado on the ground are in the range of 5 million watts for an F1 tornado, to 5 billion watts for an F5. The effect on the air of the thermalized energy is, of course, to increase its buoyancy, accounting for the vigorous updraft at the base of the vortex, which cannot be explained in any other way.

Here is the link. The quote is in a pop-up that appears if you hover over the question in the right-hand sidebar, "Are there electromagnetic or magnetohydrodynamic explanations for the development of tornadoes?"

TORNADO FAQs

anonymity

lol @ chaos theory jokes =s

ak666666

With much more greenery, IR would be reflected back more, ground will heat up less and hot air will rise up less. This could lessen tornado force. No?

DoggerDan

Some dwellings are far more tornado-resistant than others. If I ever moved to Kansas, I wouldn't life in a traditional two-story house!

atheerzahroon

I think if we can make a thermodynanic changes to the maximum or minimum pressure regions of tornado we can control it. Is there a pressure diagram of these regions ?