From the University of Hawaii at Manoa, more of the “more heat = more hurricanes” meme.
Threshold sea surface temperature for hurricanes and tropical thunderstorms is rising
IMAGE: The average tropical sea surface temperature (black) and an estimate of the sea surface temperature threshold for convection (blue) have risen in tandem over the past 30 years.
Scientists have long known that atmospheric convection in the form of hurricanes and tropical ocean thunderstorms tends to occur when sea surface temperature rises above a threshold. The critical question is, how do rising ocean temperatures with global warming affect this threshold? If the threshold does not rise, it could mean more frequent hurricanes.
According to a new study by researchers at the International Pacific Research Center (IPRC) of the University of Hawaii at Manoa (UHM), this threshold sea surface temperature for convection is rising under global warming at the same rate as that of the tropical oceans. Their paper appears in the Advance Online Publications of Nature Geoscience.
In order to detect the annual changes in the threshold sea surface temperature, Nat Johnson, a postdoctoral fellow at IPRC, and Shang-Ping Xie, a professor of meteorology at IPRC and UHM, analyzed satellite estimates of tropical ocean rainfall spanning 30 years. They find that changes in the threshold temperature for convection closely follow the changes in average tropical sea surface temperature, which have both been rising approximately 0.1°C per decade.
“The correspondence between the two time series is rather remarkable,” says lead author Johnson. “The convective threshold and average sea surface temperatures are so closely linked because of their relation with temperatures in the atmosphere extending several miles above the surface.”
The change in tropical upper atmospheric temperatures has been a controversial topic in recent years because of discrepancies between reported temperature trends from instruments and the expected trends under global warming according to global climate models. The measurements from instruments have shown less warming than expected in the upper atmosphere. The findings of Johnson and Xie, however, provide strong support that the tropical atmosphere is warming at a rate that is consistent with climate model simulations.
“This study is an exciting example of how applying our knowledge of physical processes in the tropical atmosphere can give us important information when direct measurements may have failed us,” Johnson notes.
Caption: Tropical ocean thunderstorms tend to occur above a threshold sea surface temperature.
Credit: Image courtesy NASA Image Science & Analysis Laboratory
The study notes further that global climate models project that the sea surface temperature threshold for convection will continue to rise in tandem with the tropical average sea surface temperature. If true, hurricanes and other forms of tropical convection will require warmer ocean surfaces for initiation over the next century.
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This work was supported by grants from NOAA, NSF, NASA, and JAMSTEC.
Captions: Figure 1. Tropical ocean thunderstorms tend to occur above a threshold sea surface temperature. Image courtesy NASA Image Science & Analysis Laboratory
Figure 2. The average tropical sea surface temperature (black) and an estimate of the sea surface temperature threshold for convection (blue) have risen in tandem over the past 30 years.
Citation: N.C. Johnson and S.-P. Xie, 2010: Changes in the sea surface temperature threshold for tropical convection. Nature Geoscience, doi:10.1038/ngeo1004.
Try, and try again, but don’t give up.
bold no bold
Got it! Who said you cant teach an old dog new tricks?
Hmm, what would Willis say? If tropical convection is the governor of the world’s temperature, then this effect says that the governor can be set to a higher temperature.
http://wattsupwiththat.com/2009/06/14/the-thermostat-hypothesis/
http://wattsupwiththat.com/2010/07/24/willis-publishes-his-thermostat-hypothesis-paper/
Folks in the US think the world turns on Atlantic hurricanes that hit us, and it’s all about rising AGW SST and land surface temperature. Hogwash. It has to do with ENSO conditions. It isn’t that these events are less or more period, it’s that they switch places depending on ENSO conditions. What came out of NOAA used to highlight this well known phenomenon. http://www.aoml.noaa.gov/hrd/Landsea/lanina/
These days, once they leave our shores, we tend to disregard their presence elsewhere on the planet and not a word is said about ENSO, a completely natural system that has been around for 1000’s of years.
Funny that, if true, this means that warmer waters will not result in large increases in convective activity, since the level they need to reach has also risen…Which means that there will NOT be more tropical cyclone activity due to this specific effect.
Seems like good news and I’m surprised it is actually getting attention since doom and gloom is much more popular…
I notice that again (as has been done many times), only the 20 year period from 1978 to 1998 is shown, that shows an effect. Including data to present is misleading, as the last 12 years alone do not show any effect (i.e., they cherry picked and used the picked period to make a straight line fit). Prior data to at least the 1930’s would show a peak to about 1940, a down turn from the 1940’s to early 1970’s, an upturn mid 1970’s to late 1990’s, and then a long peak that is thought to then go down. This is typical mis-information and should be thrown out. They should be ashamed.
By the way, it is not at ALL clear how they think that this relates to the upper tropospheric temps. Can someone explain this odd logic to me?
http://news.discovery.com/tech/twitter-chatbot-counters-anti-global-warming-tweets.html
Twitter taken over by the global warming conspiracy.
Cutting out the outliers – 1985 and 1998, doesn’t the trend seem pretty much flat? It seems to using my very scientific “stare at the graph and try and work it out in your head” method.
Protect the models! They are our only hope now. Protect the models even if it costs your sanity! Even if it means the abandonment of logic, reason, the scientific process and a reversal of cause and effect. We must protect the models or the Skeptics will win!
Interesting post, from a what were they thinking kind of viewpoint. The phrasing of this line is interesting.
This study is an exciting example of how applying our knowledge of physical processes in the tropical atmosphere can give us important information when direct measurements may have failed us,” Johnson notes.
Now do they mean
a) that they have not yet managed to create an experiment that will accurately measure what they are looking for?
b) They have decided that they KNOW what the data will be when the find a way to accurately measure it.
In case “a” if they have not managed to find a way to measure the data that forms a major part of their thesis why are thy publishing? Their conclusions have to be premature if not widely optimistic give what I read in the posting.
In case”b” if they know what the data is they should have presented their proof, is it just me or is there a problem with estimating temperature levels from satellite data of tropical rainfall.
Assuming they have an accurate algorithm for the rainfall vs temperature question, do they have complete satellite data coverage? I saw nothing regarding the methodology of their work and that to my mind ( or whats left of it anyway) is a matter of concern. Without that I am of the opinion the data is being created out of whole cloth, and before I get slagged for questioning the validity of the work, it is the authors job to make sure I have the answers to these questions, without the answers or at least something resembling a usable methodology the whole premise of the paper is suspect.
Did we not have this conversation regarding tree rings… sometimes you really need to beat them about the head and shoulders to get their attention
I don’t know what you guys are reading, I’m reading that the threshold for hurricane formation is increasing with increasing tropical temp, therefore the formation of hurricanes is becomming more DIFFICULT. This is consistent with the data that says ACE is decreasing. I’m not reading “more heat = more hurricanes”. If anything, I’m reading “more heat = less hurricanes” which is precisely the opposite of what AGW theory predicts….
Andrew,
“Can someone explain this odd logic to me?”
Without reading the paper, it is difficult to say; I’m not going to pay $30 or so to read about research results taxpayers already funded..
Hoping Dr. Ryan Maue might comment on this article . . .
I hate summaries like this, you don’t get the detail you need to understand what was really done.
For instance, what is this threshold temperature, where is its derivation? Sounds like a meaningless number until I see a derivation. I suppose I can assume it is an ocean surface temperature above which convection from rising evaporating water vapor can create a tropical storm/hurricane. If this is accurate, why wouldn’t it rise with ocean temperatures? There’s other studies that have demonstrated that even a fairly static area of any ocean transfers a lot of heat between the upper atmosphere and the ocean surface. In fact I remember Anthony posting a link to one noting that the reason clouds above open ocean form in those particular shapes (octagons?) was due to convection.
So if a “static” (non stormy) ocean surface well ahead of any tropical storm has already partially smoothed/equalized the energy gradient between surface and troposphere, why wouldn’t the threshold temperature for hurricane generation follow in lock-step? Seems like it would go without saying to me, but then again, I’m not a deep-pocketed bachelor looking for a tax writeoff.
Their knowledge is so complete they don’t need measurements.
How does that go, you can’t explain anything until you put a number to it.
And first you make sure your numbers are correct. If your measuring you make sure your measurements are correct.
I could be wrong.
You could get your numbers from your knowledge.
stevengoddard says:
November 9, 2010 at 5:47 am
Yes, you are one of us that understands physics of mixing. ITGS! (It’s the gradient, stupid). Temperature flows from high temp. to low temp.—winds flow from high pressure to low pressure. Maybe the warm-earthers missed eighth grade physics class??
In tandem means one following another, not moving jointly.
Blue line is a maths model of the data. (based on 2010 release 3)
http://www.gpsl.net/climate/data/sealevel-jason-geosat.png
I’ve been waiting for confirmation before saying much in public. The huge delay (many months) by Colorado in publishing what is 10 day data when it seemed clear sea level was going flat, suggested it was true.
There is a lot of background, far too much for here. The model is predictive, can be developed from earlier data. It is irrational that it holds in the long term, yet much the same is found in historic data records.
The origin? There is an excellent fit with magnetic related solar. This suggests something like clouds as involved. Lag solar to sea level is a little under 4 years.
Solar seems to fit satellite tight tropical temperature with a few months lag.
This might give a conceptual view, was not intended for general publication
http://www.gpsl.net/climate/data/solar-sea-temperature-lags.pdf
Solar is from NASA/Greenwhich dataset, a function of the data and is a dominant term, which came as a surprise when I first noticed it. What exactly it is would be useful to know.
I’ll pull in the new jason data sometime. Doubt it will alter much.
When I do it might be good to publish a spreadsheet. This has the useful property of being timestep agnostic making comparison with other datasets easy.
“This study is an exciting example of how applying our knowledge of physical processes in the tropical atmosphere can give us important information when direct measurements may have failed us,” Johnson notes.
WOW, Reading this made my head hurt 🙁
Does any one else think that it is scary that a “scientist” could say such a thing and that a reporter would publish it as if it is reasonable scientific statement? Post-normal science indeed! At this rate, its not going to be too far into the future when NOAA, NASA, and the NSF starts funding research into crystal therapy.
MattN says:
November 9, 2010 at 7:52 am
I don’t know what you guys are reading, I’m reading that the threshold for hurricane formation is increasing with increasing tropical temp, therefore the formation of hurricanes is becomming more DIFFICULT. This is consistent with the data that says ACE is decreasing. I’m not reading “more heat = more hurricanes”. If anything, I’m reading “more heat = less hurricanes” which is precisely the opposite of what AGW theory predicts….
Quite. It can be rather dispiriting reading this blog at times. Many commenters can’t distinguish a paper which supports their point of view from one which undermines it.
DesertYote says:
November 9, 2010 at 10:53 am
It didn’t hurt my head, but my eyes bulged and my jaw fell on the floor. I hope the context this is from differs from how it sounds, but it sounds to me as though Johnson is well on the track to taking “our knowledge of physical processes” and writing papers that are backed only by climate models. No need to handle any of that dirty data, let alone take any action when models and data might disagree.
Ah, for the good old days when scientists took observations and used them to elucidate how the world behaves. It’s so much simpler now that you can skip the first part.
Briso says: MattN says: “…I’m reading that the threshold for hurricane formation is increasing with increasing tropical temp, therefore the formation of hurricanes is becomming more DIFFICULT. This is consistent with the data that says ACE is decreasing. … I’m reading “more heat = less hurricanes” which is precisely the opposite of what AGW theory predicts….”
“Quite. It can be rather dispiriting reading this blog at times. Many commenters can’t distinguish a paper which supports their point of view from one which undermines it.
You’ve a point there, Briso, except that “less (sic) hurricanes” means fewer heat-shedding events, which means…AAAAAAAHHHH!!! TIPPING POINT! TIPPING POINT!!
The paper is garbage, anyway. Drivel. Tripe. Robustness…
Alan Moorhouse says: “…Cutting out the outliers – 1985 and 1998, doesn’t the trend seem pretty much flat?…”
Yeah, I noticed that. I was going to do a takeoff and check the slope and the r² value, but don’t have time. I noted the lack of error bars and decided it’s pretty much nonsense.
They find that changes in the threshold temperature for convection closely follow the changes in average tropical sea surface temperature, which have both been rising approximately 0.1°C per decade.
I’m not a meteorologist, but it sounds to me they are only saying that, if the SST’s rise a certain amount – and therefore that the surface air will be able to hold more water vapor – then as that surface air rises, at some point higher its temperature will have to fall by the same amount in order for it to rain, in addition to whatever other amount it would have had to fall without the extra initial SST rise. Huh?