Dr. Jeff Masters' WunderBlog

Stronger SST-intense hurricane link?
Posted by: Dr. Jeff Masters, 02:53 PM GMT del 12 Aprile 2006 +0
A link between global warming and increased intense hurricane activity is a very hot topic in hurricane research right now, and many new papers on the subject will be published this year. The latest paper, published March 15 in the on-line version of Science, Science Express, finds stronger evidence that the increasing number of Category 4 and 5 hurricanes globally since 1970 is directly linked to increases in Sea Surface Temperature (SST). The paper by Hoyos et al. was called, "Deconvolution of the Factors Contributing to the Increase in Global Hurricane Intensity". Two of the co-authors--Peter Webster and Judith Curry of Georgia Tech--were also authors of a paper published in Science magazine in 2005 that reported a worldwide increase in the number of Category 4 and 5 hurricanes of 80% in the past 30 years. The paper, (Webster et al., 2005), titled "Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment", linked the rise in storms to increasing sea surface temperatures and concluded that "global data indicate a 30-year trend toward more frequent and intense hurricanes." As I reported in my blog on the subject, their findings should be considered as preliminary evidence that the global incidence of Category 4 and 5 hurricanes may be increasing. There are some severe problems with the quality of the data set used to, and there are good reasons to believe that the actual increase in Category 4 and 5 hurricanes is far lower than the 80% increase found by Webster et al.

The new paper by Hoyos et al. uses a mathematical technique called information theory to study the relative effects of SST, wind shear, humidity, and wind patterns on global incidence of Category 4 and 5 hurricanes. The study found that only SST can explain the observed increase in these storms. One thing I like about the new study is that it directly addesses the issue of data quality in the record of Category 4 and 5 hurricanes, something the authors neglected to do in their previous paper. The authors write, "Recently, the quality of the hurricane data has been questioned and even a reanalysis of the tropical cyclone databses has been suggested in order to ratify that the results of recent studies are not due to problems in the data." The authors go on to say that they performed their analysis without using suspect data from the North Indian Ocean, and found no difference in their results. Well, that's not too surprising, since the number of Category 4 and 5 hurricanes in that ocean basin represents only about 2% of the global total. What I would have liked to have seen was the analysis re-done using the latest reanalyzed results for typhoons from the Western Pacific, which accounts for 48% of global Category 4 and 5 hurricanes. In a paper accepted for publication but not yet finalized, Knaff and Zehr (2006) make convincing arguments that typhoon intensities during the 1973-1986 period were too low due to measurement error, and the number of Category 4 and 5 storms in the region have been roughly constant for the past 50 years. Dr. Knaff and Charles Sampson have performed a preliminary re-analysis of maximum typhoon intensities for the period 1966-1987 based on the Knaff and Zehr (2006) results. In a paper to be presented at the upcoming 27th Conference on Hurricanes and Tropical Meteorology (April 24-28, 2006), they show that after correcting for the measurement errors, the number of Category 4 and 5 typhoons during the 1966-1987 period increased by 1.5 per year, leaving only a slight upward trend in Category 4 and 5 typhoons during the period 1970 - 2004. The 16% increase in Category 4 and 5 typhoons found by Webster et al. during the past 15-year period is reduced to just 3%. I suspect that if the information theory techniques of Hoyos et al. were applied to this modified data set, the connection between SST and an increase in global Category 4 and 5 hurricanes would be much weaker.

The realclimate.org blog has more information on the paper, along with links to quotes in the media from many of the scientists involved in the hurricanes/global warming debate.

My next blog will be on Friday. Apparently, NHC has "found" a new Atlantic subtropical storm that formed in 2005, bringing the total for the season to 28 named storms. If the final report on this new storm has been issued, I'll discuss that.

Jeff Masters

references
Hoyos, C.D., P.A. Agudelo, P.J. Webster, and J.A. Curry, "Deconvolution of the Factors Contributing to the Increase in Global Hurricane Intensity", www.scienceexpress.org, 16 March 2006, 10.1126/science.1123560.

Knaff, J.A., and R.M. Zehr, "Reexamination of Tropical Cyclone Wind-Pressure Relationships", accepted to Weather and Forecasting, 2006.

Webster, P.J., G.J. Holland, J.A. Curry, and H.-R. Chang, "Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment", Science, 309, 1844,1846, 16 September 2005.
Alpha Chi Omega missing a wall (Arian)
The twister tore a whole wall from the sorority house and detroyed everything around it.
Alpha Chi Omega missing a wall
Categories: Climate Change
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Reader Comments
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101. Levi32 12:17 AM GMT del 13 Aprile 2006    
Oops forgot the link
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
102. DAVIDKRZW 12:22 AM GMT del 13 Aprile 2006    
and ts as well
104. Inyo 12:43 AM GMT del 13 Aprile 2006    
I think the root of this political issue is this:

Oil companies sell oil, if they sell less oil they make more money. Therefore, it is in the interest of the oil companies to support research that denies global warming as a factor. Of course to some extent this is fair, if an unfair accusation is being made about oil's effects we should find out. However, it seems that there are a lot more people who profit from the con argument (oil companies and politicians) than the pro warming argument (only politicians, maybe?). I never really understood who is profiting from the 'pinko liberal' greenhouse warming argument... who makes money off of the belief that we are warming the climate? biodiesel manufacturers? Maybe since i am a liberal i can't see the liberal bias, but i don't believe it exists.

anyway, sorry to get political...

i'm waiting on a big (non tropical) low to pass over us on Friday.. it may be the last spring storm of the year for so-cal so i'll enjoy it while i can
Member Since: Settembre 3, 2002 Posts: 42 Comments: 765
105. Inyo 12:44 AM GMT del 13 Aprile 2006    
oops, that above should read 'if they sell less oil they make less money'
Member Since: Settembre 3, 2002 Posts: 42 Comments: 765
106. ProgressivePulse 12:44 AM GMT del 13 Aprile 2006    
I tell ya what, the soon to be CUL is trying, I think I can, I think I can. Please return all drool tables to thier full upright and locked positions until June, shear levels and the large drape approacing aught to knock it out.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
107. ProgressivePulse 12:46 AM GMT del 13 Aprile 2006    
Biggest weather event is going to be the drop in winds in sfl
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
108. ProgressivePulse 12:47 AM GMT del 13 Aprile 2006    
<--- Doing a rain dance, kind of futile at this point.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
109. Trouper415 12:48 AM GMT del 13 Aprile 2006    
The fact that there are projections of such amazing climate change in this CENTURY is reason enough to start making changes to start lowering C02 emissions now. Its not like we all have to live in caves. The changes are needed anyways in the comming years as oil production has basically peaked and the years of cheap oil are over.
Member Since: Settembre 22, 2005 Posts: 5 Comments: 637
110. HurricaneMyles 12:49 AM GMT del 13 Aprile 2006    
One could only hope this thing tries to develope a little more. Maybe it can get some decent convection going and give us some desperatly needed rain here SWFL.

<---- Begins doing rain dance with Progressive.
Member Since: Gennaio 12, 2006 Posts: 5 Comments: 827
111. ProgressivePulse 12:50 AM GMT del 13 Aprile 2006    
$2.86 a gallon here, ouch.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
112. ForecasterColby 12:50 AM GMT del 13 Aprile 2006    
I just posted a new blog, come over for some fun!
113. DAVIDKRZW 12:51 AM GMT del 13 Aprile 2006    
but you do not want the rain all at one time you get flooding but a little rain in FL will be nic
114. ForecasterColby 12:52 AM GMT del 13 Aprile 2006    
Levi, what models are you looking at? Only one I see that even recognizes its existance is the GFS, which keeps it stalled until it dies.
115. ProgressivePulse 12:52 AM GMT del 13 Aprile 2006    
Rain is one thing, I am glad they figured out how to solve the stinch in the water. I was getting worried about that, rather unpleasent in the shower.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
116. DAVIDKRZW 12:52 AM GMT del 13 Aprile 2006    
my gas is up to 2.93$
117. ProgressivePulse 12:54 AM GMT del 13 Aprile 2006    
David, SFL is equiped to handle large amounts of rain at a time, Bring it on>
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
118. Levi32 12:55 AM GMT del 13 Aprile 2006    
Colby, the NOGAPS has a low in the Caribbean which is this low but it moves it south.
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
119. HurricaneMyles 12:56 AM GMT del 13 Aprile 2006    
A lot of water will not be a problem here in SWFL. The creeks around my house are about 5-6 below normal level and everywhere else seems to be about the same.
Member Since: Gennaio 12, 2006 Posts: 5 Comments: 827
120. DAVIDKRZW 12:57 AM GMT del 13 Aprile 2006    
ProgressivePulse ok how about 2ft of rain come on to my blog for some fun tonight and ever one on her can come in too
121. Levi32 12:58 AM GMT del 13 Aprile 2006    
Look at the WV loop. It has some "outflow" to its north.Link
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
122. Levi32 01:00 AM GMT del 13 Aprile 2006    
Hey guys look at this. Normaly the cuba radars update only once an hour. I just found a radar that updates every 15 minutes! The disturbance is coming into the radar view take a look! Link
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
123. ProgressivePulse 01:01 AM GMT del 13 Aprile 2006    
That would be all the shear about to knock it out
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
124. HurricaneMyles 01:02 AM GMT del 13 Aprile 2006    
Easy Levi. All thunderstorms have outflow. Right now it doesn't even have a closed off surface low. It doesn't look too promising, imo.
Member Since: Gennaio 12, 2006 Posts: 5 Comments: 827
125. HurricaneKing 01:04 AM GMT del 13 Aprile 2006    
I give it 5%.
Member Since: Luglio 6, 2005 Posts: 71 Comments: 2430
126. Levi32 01:04 AM GMT del 13 Aprile 2006    
I'm fine Myles, just noting. It didn't start outflow on satellite until the end of the loop so it is becoming more pronounced. Besides, I just stated early this morning that this wouldn't develop.
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
127. Levi32 01:06 AM GMT del 13 Aprile 2006    
That should be noticing not noting.
Member Since: novembre 24, 2005 Posts: 586 Comments: 25441
128. turtlehurricane 01:07 AM GMT del 13 Aprile 2006    
dont worry about this disturbance, its really nothing
Member Since: Luglio 22, 2005 Posts: 227 Comments: 466
129. DAVIDKRZW 01:08 AM GMT del 13 Aprile 2006    
i give it 20% to 50% ch of be comeing some in but if only the shear move out of the way a little bit if not i give it 10% to 15% ch of be comeing some in
130. turtlehurricane 01:13 AM GMT del 13 Aprile 2006    
i just looked at all anlysises. it appears it may form a surface low but, it will only do this when the cold front hits it and thus, it would be barciclonic. its more of a nontropical gale center forming and it has absolutely no chancem of hitting the u.s.
Member Since: Luglio 22, 2005 Posts: 227 Comments: 466
131. DAVIDKRZW 01:21 AM GMT del 13 Aprile 2006    
Link


sea temps update
133. Skyepony (Mod) 01:32 AM GMT del 13 Aprile 2006    
My internet acsess has been come & go from the cool wind blowing off that thing. This Naval Java shear model has been insistant of something forming around the Bahamas, headed for south FL for days now...unwavering. We started getting some very scattered cold showers from the east off it this morning. For the last 2 1/2 days, at times, low level tropical looking clouds blow in at a quick clip but on a cold wind. I hope someone gets some rain, but don't expect it to be warm...
Member Since: Agosto 10, 2005 Posts: 144 Comments: 29268
134. Skyepony (Mod) 01:40 AM GMT del 13 Aprile 2006    
I like NOAA's new Nowcast for SST, currents, salinity, sea surface height & etc. ~ Here's the 72 hr forecast for SST in 3-D... Link
Member Since: Agosto 10, 2005 Posts: 144 Comments: 29268
136. Skyepony (Mod) 02:03 AM GMT del 13 Aprile 2006    
Your looking at the whole atlantic...

You can select on the top ~gulf, west atlantic zoom, etc. For the N Carribian, gulf & W Atlantic (that's the west Atlantic zoom) Max current SST temp~ 30.15ºC

See the Nogaps #78 forecast to develop storm? How longs that been there? I've been denied by the wind to keep up.
Member Since: Agosto 10, 2005 Posts: 144 Comments: 29268
137. ProgressivePulse 02:04 AM GMT del 13 Aprile 2006    
<--- See's the defensive line from the early 90's Bears progressing through FLA
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
138. gippgig 02:10 AM GMT del 13 Aprile 2006    
Does that unnamed subtropical storm (& subtropical storms in general) count toward the yearly ACE total?
Member Since: Dicembre 5, 2005 Posts: 0 Comments: 55
139. ProgressivePulse 02:24 AM GMT del 13 Aprile 2006    
But I will say, that I see something in the southern area of a certain low pressure system that nobody is watching, of course, that really resembles a certain something TRYING to get a name for itself.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
141. ProgressivePulse 02:31 AM GMT del 13 Aprile 2006    
Nothing really Micheal, just looks like the area by the Bahama's trying to grab a feed from the south west. I was being sarcastic on the "system that nobody is looking at" cause everone is. It is trying it's hardest to get going for sure.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
142. ProgressivePulse 02:33 AM GMT del 13 Aprile 2006    
Not happening though, just crazy to look at this time of year.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
143. ProgressivePulse 02:46 AM GMT del 13 Aprile 2006    
Life @ 21N 71W is looking kinda sparky
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
144. ProgressivePulse 02:47 AM GMT del 13 Aprile 2006    
25N 71W that is
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
145. ForecasterColby 03:19 AM GMT del 13 Aprile 2006    
Progressive, there has been a storm before in April. I'd say this has a chance, if not a good one.
146. ForecasterColby 03:24 AM GMT del 13 Aprile 2006    
What's looking sparky there progressive?
147. ProgressivePulse 03:25 AM GMT del 13 Aprile 2006    
I hold strong reserves but man if there were just a little less shear, we would have Alberto. Visible rotation is showing well, man you see lines from the SW you have to wonder. Shear will get it though.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
148. ProgressivePulse 03:26 AM GMT del 13 Aprile 2006    
approx 25n 71w colby.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
149. ProgressivePulse 03:28 AM GMT del 13 Aprile 2006    
A little below 25, visible.
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
150. ProgressivePulse 03:31 AM GMT del 13 Aprile 2006    
Follow the line around the hook!
Member Since: Agosto 19, 2005 Posts: 5 Comments: 4324
151. Skyepony (Mod) 03:33 AM GMT del 13 Aprile 2006    
the 25n 71w was the one i was refuring to as the NOGAPS #78 & here's the NOGAPS 850 vort loop

How many runs has #78 been forecasted?
Member Since: Agosto 10, 2005 Posts: 144 Comments: 29268

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About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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