Warmer Water, SUPER HURRICANES

By: Dr. Jeff Masters , 12:33 PM GMT on July 24, 2007

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The July 2007 issue of Scientific American has an article called "Warmer Oceans, Stronger Hurricanes" (referred to as "Warmer Water, SUPER HURRICANES" on the cover). The article is written by Dr. Kevin E. Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research, and a lead author on the landmark 2007 climate report issued by the UN's Intergovernmental Panel on Climate Change (IPCC). The article makes the case that "evidence is mounting that global warming enhances a cyclone's damaging winds and flooding rains." The article presents some solid evidence to substantiate that point of view, which I will share below. However, I was disappointed in the general tone of the piece, which was over-hyped and did not paint an objective view of the current scientific thinking on the global warming/hurricane issue.

The hype
First off, the reader is hit with a dramatic full-page artist's depiction of the global super-hurricane of the future--a massive 5000-mile diameter Caribbean storm the size of North America. The storm's 200-mile eye is wider than the Florida Peninsula! Whoa, I said when looking at the whopper "SciAmicane". No doubt many readers perusing the magazine, trying to decide whether to buy it, had the same reaction and plunked down their $5 to read about this grim threat. OK, lets talk reality here. The largest tropical cyclone on record, Supertyphoon Tip of 1979, had a diameter of 1380 miles--less than one third the size of the SciAmicane. A storm like the SciAmicane cannot physically exist on Earth unless the oceans were to super-heat to about 122°F (50°C). Only an asteroid impact or similar calamity could create such a hypercane. Even the most extreme global warming scenarios do not heat the oceans to 122°, so the SciAmicane is there to sell magazines, not to illustrate what global warming might do to hurricanes.


Figure 1. Comparison of sizes: the Earth, the largest tropical cyclone on record (Supertyphoon Tip of 1979, 1380 miles in diameter), and the recently discovered hurricane-like vortex on Saturn (the Saturnicane). The "SciAmicane" is about the same size as the Saturnicane--5000 miles across.

The article also calls attention to 2004, when "an unprecedented four hurricanes hit Florida, and 10 typhoons made landfall in Japan". I've erroneously made this statement, too, but the truth is that Japan was hit by only four typhoons in 2004. Ten tropical cyclones that were of typhoon strength at some point during their life did hit, yes, but six of these had decayed to tropical storm or tropical depression strength by the time they hit Japan. The article then refers to a "consensus explanation" emerging to explain recent hurricane activity patterns, and "that explanation forebodes meteorological trouble over the long term." I'd say that the issue is still very much under dispute. In fact, the consensus statement on hurricanes and climate change adopted by the World Meteorological Organization in December 2006, in response to the recommendations of a panel of 125 hurricane researchers was thus: "Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point." Trenberth's article gives a list of four publications to read in the "more to explore" section, but none of these include the recent articles that call into question the strength of the global warming/stronger hurricane connection. (I apologize for not reviewing the many excellent articles that have appeared on this subject of late!)

The good science
There's quite a bit of good science in the article, which is worth reading if one keeps in mind its biases. In particular, I like the discussion of how global warming has affected precipitation and atmospheric water vapor. The 0.6°C (1.0°F) rise in Sea Surface Temperatures (SSTs) globally since 1970 has increased water vapor in the atmosphere by 4%, thanks to increased evaporation. This in turn has led to an 8% increase in global precipitation. Trenberth makes the point that no given hurricane can be blamed on global warming, but one can say 8% of a given storm's rainfall is due to global warming. There's also a nice discussion about how weaker than normal trade winds over the tropical Atlantic in 2005 caused less evaporational cooling than normal, allowing the ocean to heat to record temperatures. Finally, the conclusion of the article is one I certainly agree with:

We would all be wise to plan for more extreme hurricane threats.

Both theory and computer models predict a 3-5% increase in hurricane winds per degree C increase in tropical SSTs, and there is concern that the actual increase may be much more than this.

Jeff Masters

For a technical treatment of hypercanes, see Dr. Kerry Emanuel's paper, Hypercanes: a possible link in global extinction scenarios.

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1841. Alec
9:43 PM EDT on July 25, 2007
I guess I should have clarified.....I meant something that actually develops into a TD/S in the short term.......I didnt specify a time period in the future BTW....LOL


Lets all be nice.....=)
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1839. KoritheMan
8:43 PM CDT on July 25, 2007
Again, I guess my behavior was a bit bad. I'm sorry. I hope you guys can forget it and move on. I'll try and say things in a nicer way next time.

I'm still convinced eye is a troll, though.
Member Since: March 7, 2007 Posts: 575 Comments: 20572
1837. eye
1:40 AM GMT on July 26, 2007
well, trust the NHC which says no development through Sat, which means..NOTHING IS OUT THERE THAT HAS POTENTIAL AT THIS TIME AND FOR THE FORSEEABLE FUTURE
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1835. KoritheMan
8:41 PM CDT on July 25, 2007
I apologize if I offended any here, just in a really bad mood tonight. Perhaps I should get off...
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1834. StormJunkie
1:38 AM GMT on July 26, 2007
Evenin Saint, the wave in the Atl is clearly on the very northern edge of the ITCZ. Still tapping some moisture, but not embedded in by any means.

And at the very least the GOM looks interesting.

Night all ☺
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1832. KoritheMan
8:41 PM CDT on July 25, 2007
Maybe next time, we'll have something tropicalish to talk about!LOL

No offense Alec, but don't we already have something tropical to talk about? o.O
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1830. weatherboykris
1:40 AM GMT on July 26, 2007
He's entitled to his opinion,isn't he?
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1829. weatherguy03
9:40 PM EDT on July 25, 2007
You da man Billy!!!
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1827. Alec
9:38 PM EDT on July 25, 2007
Well SW, its good to get one's foot in the door early, so job prospects for me will be a little brighter in the future!LOL

Maybe next time, we'll have something tropicalish to talk about!LOL
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1826. KoritheMan
8:40 PM CDT on July 25, 2007
no jp the models and nhc have spoken lol goodnight

Models are overrated. Extremely... NHC I can trust, but not models.
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1824. SAINTHURRIFAN
1:37 AM GMT on July 26, 2007
no jp the models and nhc have spoken lol goodnight
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1823. KoritheMan
8:38 PM CDT on July 25, 2007
SAINT has spoken


ok time for us all to leave guys, see you on August 15th when we see our next storm


Certainly no development there, jp. The wishcaster has spoken.
Member Since: March 7, 2007 Posts: 575 Comments: 20572
1822. eye
1:37 AM GMT on July 26, 2007
yeah, people are stretching in this blog for development, all the stuff in the Catlantic is ITCZ related, and the BOC is just a blob will no future.....it has been a long time since this blog has had a descent system to forwishcast.....
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1820. Buhdog
1:35 AM GMT on July 26, 2007
Tropical 07 Why do you always post in BOLD?
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1818. SAINTHURRIFAN
1:34 AM GMT on July 26, 2007
no development in boc and certainly none in central atlantic strictly itcz induced
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1817. CaicosRetiredSailor
9:34 PM EDT on July 25, 2007
: texascanecaster1
....first you have to put a stamp on it.
CRS
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1815. sonofagunn
1:34 AM GMT on July 26, 2007
Some ships have reported winds with a Westerly component around 27N

Buoy & ship data

... *EDIT* but that's way too far North to be associated with the convection in the BOC.
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1814. CaicosRetiredSailor
9:30 PM EDT on July 25, 2007
Preview of Coming Attractions

CaicosRetiredSailor

will post his first blog tomorrow
featuring many of the present company
stay tuned....
CRS
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1812. Alec
9:32 PM EDT on July 25, 2007
yeah SW! Good having you there.....maybe you can come in again and Ill show you more of my research! Its good experience being there....
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1811. weathermanwannabe
9:28 PM EDT on July 25, 2007
But for the current shear in the GOM, we would probably have a TD in the BOC by tommorow based upon the persistence over the last several hours and the most recent SAT loops; that is some impressive convection right now in the BOC...
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1808. CaicosRetiredSailor
9:29 PM EDT on July 25, 2007
Eye Eye
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1806. Drakoen
1:28 AM GMT on July 26, 2007
Wind shear is 20kts in the BOC. i am not expecting any development.
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1805. Buhdog
1:24 AM GMT on July 26, 2007
Not you Eye...weird you posted right before I said that
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1804. Alec
9:23 PM EDT on July 25, 2007
might be able to pull off a "Barry" but not likely.....even though satellite presentation looks suspicious, there doesnt appear to be a low level circulation.....Mostly a mid/upper level swirl.....
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1802. CaicosRetiredSailor
9:22 PM EDT on July 25, 2007
SW
Thanks, I appreciate you following up on that.
CRS
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1801. sporteguy03
1:17 AM GMT on July 26, 2007
Photo Sharing and Video Hosting at Photobucket

Rainbow for JP
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1800. watchingnva
1:20 AM GMT on July 26, 2007
def. a ciculation trying to form in the BOC....if you watch the vis. loops you can just see a spin to the sw of the big blowup of convection. Lets see what we have in the morning...should be interesting.
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1799. Drakoen
1:21 AM GMT on July 26, 2007
eye i said we need to watch it. And that image isn't as fine as the RGB loop. It has a circulation and the model have something developing in that area.
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1798. Buhdog
1:14 AM GMT on July 26, 2007
whether it is troughiness or not that causes low pressure gradients in the gulf.....too much for an extended period will = trouble.

pretty simple to understand.....all we need is for some relaxing (which is so hard to nail down)of shear and poof!!!!!!

We may have something in the Gulf....keep an "EYE" out
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1797. eye
1:18 AM GMT on July 26, 2007
Drak, looks like a few scattered showers, no big deal....
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1794. sporteguy03
1:14 AM GMT on July 26, 2007
It looked like Dr.Masters Rainbow
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1793. guygee
1:07 AM GMT on July 26, 2007
Still no westerly wind component at buoy Station 42055 - Bay of Campeche as of 0050 GMT. Whatever cyclonic swirl that was observed on the earlier visible loops was most likely not at the surface, as the position of the convection on IR is now well north of the buoy location at 22.01 N 94.05 W.
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1791. Drakoen
1:11 AM GMT on July 26, 2007
definately need to watch this. has a circulation and could increase the convection during diurnal max.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.