# How intense will storms get? New model helps answer question

##### Jul 08, 2008

A new mathematical model indicates that dust devils, water spouts, tornadoes, hurricanes and cyclones are all born of the same mechanism and will intensify as climate change warms the Earth's surface.

The new equation, developed by University of Michigan atmospheric and planetary scientist Nilton Renno, could allow scientists to more accurately calculate the maximum expected intensity of a spiraling storm based on the depth of the troposphere and the temperature and humidity of the air in the storm's path. The troposphere is the lowest layer of Earth's atmosphere.

This equation improves upon current methods, Renno says, because it takes into account the energy feeding the storm system and the full measure of friction slowing it down. Current thermodynamic models make assumptions about these variables, rather than include actual quantities.

"This model allows us to relate changes in storms' intensity to environmental conditions," Renno said. "It shows us that climate change could lead to increases in how efficient convective vortices are and how much energy they transform into wind. Fueled by warmer and moister air, there will be stronger and deeper storms in the future that reach higher into the atmosphere."

Renno and research scientist Natalia Andronova used the model to quantify how intense they expect storms to get based on current climate predictions. For every 3.6 degrees Fahrenheit that the Earth's surface temperature warms, the intensity of storms could increase by at least a few percent, the scientists say. For an intense storm, that could translate into a 10 percent increase in destructive power.

Renno's model is what scientists call a "generalization" of Daniel Bernoulli's 18th-century equation that explains how airplane flight is possible. Bernoulli's equation basically says that as wind speed increases, air pressure decreases. It leaves out variables that were considered difficult to deal with such as friction and energy sources (which, in the case of a whirling storm, is warm air and condensation of water vapor.) And in certain idealized situations, omitting that information works fine.

But by including these additional variables, Renno was able to broaden Bernoulli's equation to apply it to more general phenomena such as atmospheric vortices.

"The laws of physics are generally very simple," Renno said. "When you make assumptions, you are not representing the simple, basic law anymore. If you don't make assumptions, your equations have those simple, basic laws in them. It gets a little more complicated to get to the solution, but you don't introduce error, and you answer is more elegant, more simple."

Renno's work bolsters studies by others who say hurricanes have grown stronger over the past 50 years as sea surface temperatures have risen. This effect has not been extreme enough for humans to notice without looking, scientists say. Hurricane Katrina and Cyclone Nargis were not the most intense storm to hit land in the past half century. Other factors contributed to the devastation they caused.

This new model helps explain the formation of spiral bands and wall clouds, the first clouds that descend during a tornado. It's clear now that they are the result of a pressure drop where the airspeed has increased.

Renno says unifying convective vortices from dust devils to cyclones will help scientists better understand them.

"This is the first thermodynamic model that unifies all these vortices," he said. "When you unify them, you can see the big picture and you can really understand what makes them form and change."

A co-investigator on NASA's Mars Phoenix Lander mission, Renno has used his new model to calculate the intensity of dust storms in Mars' polar regions. He found that at the Phoenix landing site dust storms can have winds in excess of 200 mph.

Source: University of Michigan

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## User comments : 4

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##### menkaur
3.7 / 5 (6) Jul 09, 2008
to me it seems that "increasing intensity of storms" is caused by media.
a) we can't predict weather for 3 days in the future... how about predicting climate for years in future?
b) climate temperature changes are too slow to cause any kind of weather

the article is just speculation
##### StillWind
3.6 / 5 (7) Jul 09, 2008
Although its good to see that Renno is refining the current models, all of which are horribly flawed and currently pretty much useless for real world application.

However, the assumption that increased global warming will increase the intensity of storms totally ignores the fact that weather is partly the result of pressure differential. As the planet warms, it does so more at the poles, and thus the differential is narrowed, instead of broadened.

If the planet does resume warming (it hasn't since 1999-2000), then storms will subside as the global temps become more uniform.

However, this will not cause a general sense of panic, and cause peoiple to give up their rights and treasure, so the truth will never be promoted.

Same as it ever was......

-zz
##### bobvd10
3 / 5 (4) Jul 09, 2008
Assumptions and not evidence are the foundation stones laid to support the %u201CReligion of man made Global Warming.%u201D This %u201CReligion%u201D is one of staunch believers that are worshiping in Blind Faith a story that the global thermal evidence does not support. Very few things are more dangerous to a society then a large group of activist that are also flowing with %u201CBlind Faith%u201D
The word %u201Cfaith%u201D is translated from the Greek pi´stis, primarily conveying the thought of confidence, trust, and firm persuasion. Depending on the context, the Greek word may also be understood to mean %u201Cfaithfulness%u201D or %u201Cfidelity.%u201D%u20141Th 3:7; Tit 2:10.
The Scriptures tell us: %u201CFaith is the assured expectation of things hoped for, the evident demonstration of realities though not beheld.%u201D (Heb 11:1) %u201CAssured expectation%u201D translates the Greek word hy%u2022po´sta%u2022sis. This term is common in ancient papyrus business documents. It conveys the idea of something that underlies visible conditions and guarantees a future possession. In view of this, Moulton and Milligan suggest the rendering: %u201CFaith is the title deed of things hoped for.%u201D (Vocabulary of the Greek Testament, 1963, p. 660)
Faith is based on concrete evidence. It is based on realities, not lies.

Blind Faith is based on incomplete stories, manipulated data, assumptions not proven and implied theories not tested or confirmed.
What is this article? It appears to be filled with assumptions and twisted facts and data manipulated to support the assumptions. Where is the Scientific method?

First off, this model is a computer program written to support the theory and not written to find the facts. And these %u201CResearch Scientist%u201D are just students trying to come up with someway of getting published. Look what is said.

1st Renno says.%u201D This model allows us to relate changes in storms' intensity to environmental conditions." %u201CIt shows us that climate change could lead to increases in how efficient convective vortices are and how much energy they transform into wind. Fueled by warmer and moister air, there will be stronger and deeper storms in the future that reach higher into the atmosphere."
OK. Now prove it. Show how the climate differential would lead to higher intensities instead of the reverse.

Next Nilton Reeno claims these measurable changes will become evident when the temperature rise is above 3.6 degrees. All of the so called %u201Cexperts%u201D are only claiming a global temperature rise of maybe 1 degree in the past 100 yrs, and even that is not currently supported by good science.
The best part of this article is the statement "The laws of physics are generally very simple," Renno said. "When you make assumptions, you are not representing the simple, basic law anymore. If you don't make assumptions, your equations have those simple, basic laws in them. It gets a little more complicated to get to the solution, but you don't introduce error, and you answer is more elegant, more simple."

The Laws of Physics are relatively simple. Let%u2019s have all the Blind faith believers in man made global warming look to the Laws of Physics and get sight on the truth.

##### GrayMouser
4.5 / 5 (2) Jul 10, 2008
Computer models written by people that don't have a complete understanding of both what's being modeled and the limitations of the computer programs are subject to GIGO: Garbage In - Gospel Out

IMHO most computer programmers are unaware of the effects of binary imprecision in the representation of floating point numbers and precision vs accuracy. Add to this that the scientists involved may unaware of what they don't know about what's being modeled AND the computer/program limitations and you can end up with complete garbage without knowing it.

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