During the past 6-years since Hurricane Katrina, global tropical cyclone frequency and energy have decreased dramatically, and are currently at near-historical record lows. According to a new peer-reviewed research paper accepted to be published, only 69 tropical storms were observed globally during 2010, the fewest in almost 40-years of reliable records.
Furthermore, when each storm’s intensity and duration were taken into account, the total global tropical cyclone accumulated energy (ACE) was found to have fallen by half to the lowest level since 1977.
In his new paper “Recent historically low global tropical cyclone activity”, Dr. Ryan Maue, a meteorologist from Florida State University, examined the last 40-years of global hurricane records and found strikingly large variability in both tropical cyclone frequency and energy from year-to-year. Since 2007, global tropical cyclone activity has decreased dramatically and has continued at near-historical low levels. Indeed, only 64 tropical cyclones were observed globally in the 12-months from June 2010 – May 2011, nearly 23-storms below average obliterating the previous record low set in 1977.
On average, the North Atlantic including the Gulf of Mexico and Caribbean Sea accounts for about 1/8 of total global tropical cyclone energy and frequency. However in 2010, the Atlantic saw 19 tropical storms, of which 12 became hurricanes as expected (and forecasted) due to the intense La Nina event and continued positive Atlantic Multidecadal Oscillation (AMO). The Atlantic Ocean’s accumulated cyclone energy (ACE) corresponded to about 1/3 of the global calendar year output while the Western North Pacific typhoon season experienced a record few number. Seasonal forecasters of Atlantic hurricanes expect a similar but somewhat tempered outcome for the 2011 season, which has yet to get underway.
While the North Atlantic continued a 16-year period of above-normal activity in 2010, the North Pacific including the warm tropical waters from China to Mexico experienced the quietest tropical cyclone season in at least 40-years of historical records. Similarly, the most recent Southern Hemisphere cyclone season, except for the disastrous impacts of Yasi, was also notably below average. All told through June 27, 2011, overall global accumulated cyclone energy and frequency has settled into a period of record inactivity.
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Abstract of paper:
Tropical cyclone accumulated cyclone energy (ACE) has exhibited strikingly large global interannual variability during the past 40‐years. In the pentad since 2006, Northern Hemisphere and global tropical cyclone ACE has decreased dramatically to the lowest levels since the late 1970s. Additionally, the global frequency of tropical cyclones has reached a historical low. Here evidence is presented demonstrating that considerable variability in tropical cyclone ACE is associated with the evolution of the character of observed large‐scale climate mechanisms including the El Niño Southern Oscillation and Pacific Decadal Oscillation. In contrast to record quiet North Pacific tropical cyclone activity in 2010, the North Atlantic basin remained very active by contributing almost one‐third of the overall calendar year global ACE.
Citation: Maue, R. N. (2011), Recent historically low global tropical cyclone activity, Geophys. Res. Lett., 38, LXXXXX, doi:10.1029/2011GL047711.
Figure 1: (Updated: June 1) Last 4-decades of Global and Northern Hemisphere Accumulated Cyclone Energy: 24 month running sums through June 1, 2011. Note that the year indicated represents the value of ACE through the previous 24-months for the Northern Hemisphere (bottom line/gray boxes) and the entire global (top line/blue boxes). The area in between represents the Southern Hemisphere total ACE.
Figure 2: (Updated: June 1) Last 4-decades of Global Tropical Storm and Hurricane frequency — 12-month running sums. The top time series is the number of TCs that reach at least tropical storm strength (maximum lifetime wind speed exceeds 34-knots). The bottom time series is the number of hurricane strength (64-knots+) TCs. The added red lines are linear trends, which serve the useful purpose of delineating the respective time-series mean, since they are flat and parallel. Updated through June 1, 2011.
I am wondering if this is solar related. It’s a hypothesis that has not been rejected nor really tested to my satisfaction. Indeed, the variance explained by solar fluctuations may not be measurable with our instruments or manifest itself in the cyclone records. We know it is non-zero, but we don’t know the sign nor the number of zeroes after the decimal point …
BDF @ur momisugly 9:34
Oooh, excellent. My only suggestion would be to remove ‘our’ and ‘has’ from the middle line.
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Eye of Chris Mooney.
Ideology? Science?
Let him write ‘Calm World’.
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Ryan, in May, 2009, I had all the pleasure of presenting your graph of ACE to a literary group’s discussion of Mooney’s ‘Storm World’. A cloud modeler moderated the discussion. Needless to say, I had fun that evening. Thank you.
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[ryanm: mooney is a moonbat leftist, i applaud your efforts in injecting some sanity]
Well – if I was one of the faithful, I’d spin it like this:
“Tropical storms rely for their creation on the difference in temperature levels between the equator and (sub)tropics. The low number of cyclones and their low energy indicates that the (sub)tropics, mid-latitudes, etc, are getting warmer. This reduces the energy gradient and less storms result.”
One of the original objections to the “more storms with global warming” was the observation that temperature gradients cause storms, not temperatures per se. However, the “more storms” meme was the more interesting, and the one that easily took hold. Less storms (“it’s not as bad as we thought”) doesn’t grab the imagination of the faithful and the MSM.
[RyanM: as the planet warms, we go back to the tropical cyclone activity levels of the 1970s when the earth was cooler… conundrum]
Looking at the bottom NH line of the top ACE graph, it looks like levels are heading down to those seen during the 70’s. Another sign that the Earth is losing energy and we can expect more cold NH winters?
Yup good paper – started with no pre-conceptions and left us wanting more. Have you tried bundling a whole bunch of global met, climate, seasonal and oceanic data together and seeing if a principal components analysis gives you anything useful. I know that’s not how you are supposed to do stats but it might allow you to formulate a hypothesis for testing.
>>goldie says: June 26, 2011 at 9:29 pm
>>As I understand it, weather is more about relative differences in temperature
>> in the atmosphere as opposed to absolute temperature
Which is one reason you can get massive planetry-wide dust storms on frigid Mars. But the wonderful climate computer model said that more heat equates to more hurricanes. And this is the same wonderful computer model that predicts
huge tax rises in the futurehuge temperatue increases in the future.The only benefit we have is that, unlike in the 16th century, we are free to believe what we want to believe, without being burned on a funerary pyre.
.
Thank you very much Dr Maue for showing un-varnished data. It is greatly appreciated by this geologist and ex-academic research scientist.
[RyanM: Activity is a generic term. Accumulated Cyclone Energy is a well-used metric of tropical cyclone activity used by NOAA and even the EPA as a “climate indicator”. It is easily calc’d by taking the maximum wind speed reported by the NHC or JTWC every 6-hours and squaring it — then add up and divide by 10^4.]
Where did the formula come from?
Thanks
Sandy
[ryanm: originally a State of the Climate report from 2000. Bell et al. — it has been used since. Kerry Emanuel devised a similar metric — v^3 and called in Power Dissipation Index for his Nature 2005 paper]
Here’s a thought, not much of one, probably. It seems deep water upwelling might dominate the Pacific. We know the surface water from 400 to 700m is quite warm, while deep water is around 3 °C. Apparently [see ref], sea water gets denser until it freezes, so deep ocean current water could potentially be colder than -1 °C. It takes over 1000 years to travel from the North Atlantic to the Eastern Pacific. While water is incompressible, the current could widen and narrow over the centuries depending on the volume sinking, like a deep water tsunami. Pulses of more or less cold water upwelling could coincide with solar activity producing synchronized heating or cooling effects.
I’m assuming the temperature doesn’t change much given the large volume and limited mixing potential of the denser current. I would expect too much mixing would sap energy through turbulence and slow or stop the flow. The outflow of warmer surface water from the Pacific into the Indian draws up the colder deep water.
The point is, events 1000-1600 years ago that affected the amount of cold water entering the global conveyor could reinforce or cancel out solar-driven events now. If we knew the volume of cold water in the pipeline and about to make an appearance, we might have a chance of doing some better prediction. Can we determine whether the water coming up in the Pacific sank during the Dark Ages, or perhaps the Medieval Warm Period? If recent upwelling is actually from the tail end of the Roman Warming, that suggests more cold water from the Dark Ages would be coming up soon. Tie that together with a napping sun, and we might be in for some cold times in the Pacific.
Do any temperature fluctuation patterns in Eastern Pacific water temps seem to match temperature estimates in the North Atlantic 1000+ years ago? Can we get any indication from Greenland ice cores (maybe δ18-O)? Does colder Greenland temp mean colder water sinking and more volume? Is there any way to date the water coming up (apparently [see ref], there is a way to date ocean water using 231Pa/230Th). Can we compare Indian Ocean sediment cores to Pacific Ocean sediment cores to confirm conveyor circulation time differences and surface temperature changes?By looking at the Indian Ocean, we might be able to predict what the Pacific will do.
http://en.wikipedia.org/wiki/Thermohaline_circulation
They could better change their crystal ball.
The only benefit we have is that, unlike in the 16th century, we are free to believe what we want to believe, without being burned on a funerary pyre.
Ralph says: June 27, 2011 at 12:21 am
I think It should be : we are still free to believe
What I find interesting about the ACE is that there is less variation year-to-year than one would imagine, when one focuses on the Atlantic alone. In the Atlantic you can notice fairly wild swings from over twenty storms one year to down around ten the next, but these wild swings don’t appear in the world-wide data.
Therefore, because the ACE is low now, you can be fairly sure it won’t be high for the next few years.
However it only takes one hurricane to spoil a summer. Just because the ACE is low doesn’t mean that a single hurricane couldn’t clobber New England.
I was looking at the tree rings on a hillside that was recently clear-cut, here in southern New Hampshire, and I noticed that most of the stumps were from trees that began growing between 1950 and 1958. I wondered if any tree that was larger than a sapling on that hillside was flattened by Carol in 1954.
Less active sun, more meridional jets, more cloud, higher global albedo, less energy into the oceans, less Accumulated Cyclone Energy.
My memory probably fails me but I thought we were promised stronger and more frequent hurricanes due to global warming. We have just had over 30 years of ‘man-made’ global warming, the ‘hottest’ 10 years on the record, and the 2 ‘hottest’ years on the record.
The result:
Promises promises
Gore, Dr. Hansen et al.
Dr. James Hansen
Dangerous human-made interference
Observations trump theory every time – “The facts don’t lie”. This is what happens when you let an astronomer / venus observer become a climate scientist.
It’s part of the disinformation campaign because the AGW theory continues to be falsified by observations.
See more of their never ending failed predictions / forecasts / projections.
Don’t expect to see this paper highlighted any time soon in the MSM still less on the BBC. One can expect the BBC to carry on reporting the very opposite.
I need to remind folks here about a few other contradictory pieces of weather/climate research.
Floods – no increase in frequency, less intense
Extreme weather events – no trend
Global precipitation – no trends
Rate of sea level rise – deceleration over 80 years
Weird weather – no trends
Forest fires – decreasing frequency
Tropical Pacific sea level rise – fell
and so on……………………
Thanks for this info Ryan, our local BOM NW Australia prediction was for above average numbers of cyclones for the last three years, then went quiet, the predicted numbers did not happen. We did however have a couple of Category 5 that missed towns and fizzled rather quickly. This while temperatures were 1-2C above average. This year is 2-3C below average so far, it will be fascinating to see what happens from November with cooler seas.
Not to worry the models cover this , as they do rains of fish and the second coming of the Lord 😉
Well, the last major hurricane to hit New York was 1938. The New England area has had many hurricane strikes in the past. So it is possible for a strong hurricane to hit New York City. If a strong hurricane hits New York and if it arrives at high tide then the storm surge could cause severe flooding. That would be the Gaia dream, because many lives would be lost, especially the homeless, and because nobody remembers all those hurricanes that hit New York in the past.
Congrats Ryan,
You got a paper published in Geophysical Research Letters about hurricanes without blaming it on global warming or GHGs. Things must be really changing on the hurricane front with the community finally accepting that tropical storms and hurricanes are driven by something else.
Your paper shows some linkage to the ENSO and the PDO, but there are probably other factors to explore as well (ie keep it coming).
As an observer of things logical and real I have noted that not one -prophecy- scientific statement uum prognostication consensus fact from the AGW camp has proven in any way to be close to the facts of real world observation. They have newspeak nailed, hot is cold and more equals less, Today big brother gives us the good news that the chocolate allowance will be increased by minus twenty percent.
Mike Sphar–Welcome! Glad to see you made it over to this neck of the internet woods. If you still visit that alarmist site and see Atmoaggie, tell him I said hi! 🙂
Dr. Maue–Thanks for the update! I find your work extremely interesting, especially considering that it has been over 1000 days since any hurricane hit the U.S. (the longest such streak since before the CIvil War, if I’m not mistaken). Now, if you could find a correlation between OHC/shear and ACE, then you might have a way of more accurately predicting storm numbers.