Stu Ostro Can Bill Gates control hurricanes?

http://www.weather.com/blog/weather/8_19894.html

July 16, 2009
Stu Ostro, Senior Meteorologist

PROBLEM #1

The first is the engineering challenge and the scale involved. The FAQ page linked to above addresses that with some numbers, and David Nolan, an associate professor of meteorology and physical oceanography at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, summed it up nicely in last Friday's article:

" 'Every couple of years there's a news story that gets picked up for some hurricane-suppression idea,' Nolan said via phone this morning. 'They're all kooky in their own way. Some of them are more plausible than others, but they all face an enormous problem of scale. ... You would have to cover an incredible area with this effect to reduce the temperature of the ocean by a significant amount.' "

Let's say for the sake of argument, though, that with enough money, it could be done.

That leads to ...


PROBLEM #2

Warmth of the water is just one factor in the intensity of tropical cyclones, and usually not the most important one.

Everything else being equal -- given the exact same tropical cyclone in the exact same atmospheric environment -- one over much warmer water will have a better chance of becoming stronger.

But it isn't that simple. The real meteorological world is complex and every situation is different. More importantly, the atmospheric environment in and around the cyclone is crucial. Is it stable or unstable? Moist or dry? Air rising or sinking? Convergence or divergence of low-level winds? Upper-level shear or outflow or a combination of the two? An upper-level anticyclone (high pressure system) or an upper low involved?

The Johns Hopkins website which displays tracks of tropical cyclones overlaid on maps of SSTs (sea surface temperatures) shows plenty of examples of tropical cyclones moving over warmer water and weakening, or moving over cooler water and strengthening.

Have there been hurricanes which exploded over warm water? Sure. Much has been made of Category 5s Katrina and Rita doing that in 2005 not only over high SSTs, but as they were also going across the "Loop Current" in the Gulf of Mexico, which has relatively warm water below the surface as well.

Okay, but how about Dean and Felix, two Category 5s in 2007?

These NOAA maps depict the "Tropical Cyclone Heat Potential" (TCHP), a measure of the warmth of the upper part of the sea. Orange and red shades indicate lots of deep warmth and TCHP, while green and blue shades indicate low TCHP. I've plotted the central pressure of Dean and Felix; the lower the pressure the stronger they were.

In each case, the main intensification phase occurred over relatively low, not high, TCHP! Why? Because water temperatures are only one factor, and the atmosphere was conducive to development.
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Some comments (including my own) in response:

It would take a lot of energy to do this. If it came from fossil fuels, it would just add to global warming. If we bring cold water up from deeper in the ocean, it will be replaced by warmer water, hastening the time when the methane hydrates melt. Very bad.
Posted by Patricia Shannon | July 18, 2009

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Hurricanes will soon be powered by the newest version of Microsoft's operating system which will freeze and hang up the hurricane until Microsoft gets the patches and bug fixes out later in the fall, thus stranding the hurricanes in the middle of the Atlantic Ocean.
Posted by billy gisher | July 18, 2009

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Go ahead and wipe our hurricanes but you better be loaded with money. I will be the first in line with the class action lawsuit to pay for my escalating water costs and dead vegetation because my yard, my neighborhood, my city and my state did not get the needed rain to replinish the water supply and keep all things watered and alive. Bill, if you have money to throw away then give it to the government so they can fix health care without taxing the rest of us.
Posted by Michael W. Jones | July 17, 2009

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Mr. Gates needs to know there are benefits to hurricanes. Heavy rains associated with hurricanes help fill dry reservoirs. (Remember religious leaders in Atlanta praying for rain a few years ago?) Rain from hurricanes also replenishes groundwater supplies which are especially critical in Florida. When the water table drops, salt water can move towards wells. Messing up our drinking water supply is a real possibility if you prevent hurricanes. Mr. Gates, please remember the Law of Unintended Consequences: because all things are connected, changing one thing can trigger other unexpected changes and problems. Don't create new problems when trying to solve an existing one. The focus should be on building hurricane resistant structures. We know how to do it.
Posted by Dr. B | July 17, 2009

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Mark, yes, that's a whole other issue. From the Neil Dorst piece I linked to: "Lastly, consider the creatures of the sea. If you suddenly cool the surface layer of the ocean (and even turn it temporarily fresh), you would alter the ecology of that area and probably kill most of the sea life contained therein. A hurricane would be devastating enough on them without our adding to the mayhem."
Posted by Stu Ostro | July 17, 2009

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Wouldn't the animals and plants in the upper strata layer of the water also be mixed? Even if they weren't forced below is coolong their environment going to be very good for them?
Posted by Mark Holbrook | July 17, 2009

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