Daily tropical cyclone intensity response to solar ultraviolet radiation
J. B. Elsner, T. H. Jagger, and R. E. Hodges
GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L09701, doi:10.1029/2010GL043091, 2010
Abstract: An inverse relationship between hurricane activity over the Caribbean and the number of sunspots has recently been identified. Here we investigate this relationship using daily observations and find support for the hypothesis that changes in ultraviolet (UV) radiation rather than changes in other concomitant solar and cosmic variations are the cause.
The relationship is statistically significant after accounting for annual variation in ocean heat and the El Niño cycle. A warming response in the upper troposphere to increased solar UV forcing as measured by the Mg II index (core‐to‐wing ratio) decreases the atmosphere’s convective available potential energy leading to a weaker cyclone. The response amplitude at a cyclone intensity of 44 m s−1 is 6.7 ± 2.56 m s−1 per 0.01 Mg II units (s.d.), which compares with 4.6 m s−1 estimated from the heatengine theory using a temperature trend derived from observations. The increasing hurricane response sensitivity with increasing strength is found in the observations and in an application of the theory. Citation: Elsner, J. B., T. H. Jagger, and R. E. Hodges (2010), Daily tropical cyclone intensity response to solar ultraviolet radiation, Geophys. Res. Lett., 37,
L09701, doi:10.1029/2010GL043091.
Figure 2. Upper air temperature and tropical cyclone intensity response to variations in solar UV radiation. (a) Change in 50 hPa temperature for a change in Mg II index given the Mg II index exceeds the given percentile. The first point to the left is the ordinary least
squares regression coefficient of temperature on Mg II index using all but the lowest 10% of the Mg II values. The next point is the regression coefficient after removing the lowest
20% of the values, and so on. The point‐wise one standarderror band is shown in grey and is computed using a sandwich estimator to account for the autocorrelation in the daily values. (b) Observed and theoretical response of tropical cyclone intensity to variations in solar UV radiation (Mg II index). The observed response is a change in a percentile of tropical cyclone wind speed for all values of Mg II index. The theoretical response is the change in a percentile of wind speed for a set of temperature responses to Mg II index values exceeding a given Mg II index percentile. The solid curve (circles) and the 90% confidence band is based on a bootstrap resampling of the daily data. The dotted curve (squares) is based on equation (2) with the temperature response estimated from NCEP reanalysis data.
Conclusions
Here we show compelling evidence that the relationship between hurricane intensity and solar activity on the daily time scale is physically linked to changes in atmospheric temperature near the top of the cyclone induced by UV radiation. This new finding sheds light on the problem of forecasting hurricane intensification. The overall greater
sensitivity of the response found in the tropical cyclone wind data compared with the heat‐engine theory and temperature data might result from the tropical cyclones themselves warming the temperature aloft and thus dampening the temperature‐UV relationship [Swanson, 2008]. It is noted the theoretical results reflect a change in the maximum potential intensity of a particular tropical cyclone while the observational results reflect a change in the daily maximum wind speed over all tropical cyclones in the
region. Since a tropical cyclone plays a role in moistening the stratosphere [Romps and Kuang, 2009] and since the dissipation of the cyclone’s energy occurs through ocean
mixing and atmospheric transport, a tropical cyclone can act to amplify the effect on the Earth’s climate of a relatively small change in solar output. On longer time scales it is
noted that a portion of the variation in tropical SST’s (0.08 ± 0.2 K) lags the Schwabe cycle by 1 to 3 years, which is roughly equal to the time required for the upper 100mlayer of the ocean to reach radiative equilibrium [White et al., 1997].
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Leif Svalgaard who brought this paper to my attention, has a full copy available for review here
He also mentions:
But see also: http://www.leif.org/research/MgII%20Calibration.pdf
Their MgII proxy for UV [see their Figure 1 is not correct. It is unclear how much that influences the result. Also, I have alerted the lead author. He said he would ‘look into it’.
If one uses Birkeland’s little terrella experiment and connect the Earth’s surface electrically to the solar system and Sun, and assuming sunspots are electric discharges on the photosphere, then a reduction in those sunspots would suggest a dropping in current density producing them. As this would be linked to the electrical energy powering the solar system, then a reduction in overall power to the solar system would then produce a parallel feature as a decrease in earth surface discharge phenomena in the atmosphere – hurricanes/cyclones/typhoons. This might also be observed in “cosmic ray flux” (aka as electric current) to the Earth.
This is the Plasma Model explanation.
Stephen Wilde says:
May 5, 2010 at 11:31 pm
You used the word possible and did not enforce the absolute rule of CO2 cause.
Your funding will now be cut off as you make too much sense and are officially booted out of IPCC records.
Leif Svalgaard (May 6 2010 3.00am)
Both explanations fit the observations but we each prefer a different explanation. I don’t accept arguments from authority given the immature state of the science and the lack of predictive ability.
The stratosphere should warm from more uv heating of the available ozone but it seems that the effect of a more positive polar oscillation may well have the power to more than offset that warming effect by reducing the quantity of ozone to cause a net cooling.
You inadvertently supported the concept when you stated elsewhere that the power of the polar oscillations (you said the Arctic Oscillation actually but no matter) was sufficient to account for observed climate variability. They can only do that if they affect the temperature and so the strength of the inversion at the tropopause and they can only do that if they can affect the temperature of the stratosphere.
To fit your view the polar oscillations would have to be driven wholly from below but they can’t be because there is no match to the behaviour of sea surface temperatures. The recent El Nino failed to push the jets as far poleward as they were pushed by similar El Ninos when the sun was more active. The negative AO prevented it. Thus I currently propose a countervailing process from above and that would be a solar induced effect on the energy flux from tropopause to space. An active sun lifts the ‘lid’ a bit allowing a greater upward flux but a quiet sun lowers the ‘lid’ a bit to restrain the upward flux. In each case the net global energy budget varies accordingly. At the same time the sea surfaces are doing their own similar flux varying thing but from below. Sometimes sun and oceans are offsetting one another and sometimes supplementing one another.
The behaviour of the polar oscillations over time will resolve the issue. The switch to a more negative AO at around the time the sun became less active is enough prima facie evidence for me at the moment. I certainly do not accept that past estimates of the scale or timing of the strength of the polar oscillations are accurate enough to be helpful. They are certainly far less well documented than variations in solar activity.
Stephen Wilde says: (May 5, 2010 at 11:31 pm)
“Hurricane intensity depends on two parameters namely the sea surface temperatures and the temperature at the tropopause.”
I know you are generalizing to keep the thread on track, and I see that you cover you ass by saying “all other things being equal”, but there are several more factors that affect hurricane intensity. Wind shear being one of the more important ones. The location of any drier air surrounding the storm that can be pulled in and proximity to land are two others.
Tom in Florida
May 6 2010 5.26 am
Thanks Tom. Yes indeed, wind shear was in my mind when I wrote that.
Bear in mind that I see all the hurricanes and cyclones as just a part of the entire global convective energy transfer system so individual storms are not critically significant.
I’m sure they’ve got cause and effect hopelessly muddled in the article itself but I don’t have the inclination to resolve the muddle for them.
They suggest that the extra uv warms the upper troposphere but in practice uv is supposed to warm the stratosphere due to the response of ozone in the stratosphere. Then they confuse the issue by also postulating a warmed upper troposphere from the storms themselves.
A warmer stratosphere would lead to less storms and a more negative AO but a warmer upper troposphere could just be a reflection of more energy being pumped up from the oceans from greater convection caused by either or both of a warmer sea surface and a cooler stratosphere.
Unfortunately they make no attempt to follow the energy flux through the entire system or relate the local effects to a global whole.
Actually isn’t the Caribbean near the end track for developing hurricanes coming in from West Africa ?
Thus one would generally on average expect to see weakening in the Caribbean area anyway compared to the cyclogenesis on the way to the Caribbean.
In fact the Caribbean is usually a weak spot in the development track before cyclogenesis reinvigorates if the hurricane gets into the Gulf of Mexico.
Are we sure that the whole analysis is not skewed by that fact ?
Louis Hissink says:
May 6, 2010 at 3:11 am
This is the Plasma Model explanation.
And is completely and utterly wrong. Electric currents are consequences of plasma motions across magnetic field lines as I have explained so many times already. The notions that electric currents from somewhere power the Sun and not nuclear fusion is absurd.
Stephen Wilde says:
May 6, 2010 at 5:19 am
Both explanations fit the observations but we each prefer a different explanation. I don’t accept arguments from authority given the immature state of the science and the lack of predictive ability.
‘Generally accepted’ is not ‘authority’, but is the considerate opinion of the scientific community based on available data and understanding of the physics. You may not understand the physics and thus prefer to ignore it.
A considerate opinion is the best sort 🙂
Leif Svalgaard says:
May 6, 2010 at 7:31 am
The notions that electric currents from somewhere power the Sun and not nuclear fusion is absurd.
Doc Svalgaard, how can fusion works under extremely high pressures and high temps? Where does it have the space to slam together molecules? Is the sun not also rotating?
Density of gases and mass create two totally different reactions when rotated. Gases want to compress to the center and mass wants to escape and expand.
In a lab, has fusion been achieved under extreme heat, pressure and rotation? No.
It is guessed that our core is nickel and took 2 billion years later to form. Where was gravity and the magnetic field then? So this statement is incorrect. Like the sun, our core has to be a compressed gas as rotation WILL NOT ALLOW mass near the center.
So any fragment from space hitting the sun will not travel very far before being pushed out.
Electrical currents are achieved by rotation and the different ring sizes as going to the heart of the core generating friction.
Our planet has a mineral coating to go through but still achieves the magnetic field.
The species living outside this coating ingest a great deal of minerals and fire synapis brain patterns simular to the lightning produced.
Joe says:
May 6, 2010 at 8:41 am
Doc Svalgaard, how can fusion works under extremely high pressures and high temps?
Fusion can ONLY work under those extremes, http://en.wikipedia.org/wiki/Nuclear_fusion .
The rest of your two posts is just nonsense.
I would suggest the ancient Druid solution to appeasing the gods. Put a bunch of AGW types like Gorge in wicker baskets in the top of oak trees at the winter solstice and torch the tree. Hey it can’t do any harm to the environment. I mean its renewable energy via the tree right?
“”” Joe says:
May 5, 2010 at 3:38 pm
Because of the tilting of this planet is in movement, ONLY one point on this planet recieves DIRECT sunlight. The rest of the planet the sunlight angles and travels further through the atmosphere. At the poles, the angle of sunlight to the surface is thousands of more miles both in mileage and through the atmosphere. “””
Have you actually done calculations to verify that slant range ? The slant range (s) = (h) / Sin (a) where (h) is the height or thickness of the atmosphere, and (a) is the angluar altitude of the sun above the horizon.
So for the sun say 5 degrees above the horizon, sin (a) = 0.087 or 1/11.5 So 20 miles of atmospheric thickness and 5 deg altitude gets you 229.5 miles of slant range. 50 miles of atmosphere gets you 573.7 miles of slant range.
Well I ignored the earth surface curvature which will lengthen the slant range; but then I also ignored the atmospheric refraction due to the density gradient of the atmosphere; and that will lengthen the slant range.
So how do you get to “thousands of more miles” ?
But Joe; your point is valid; and the extra range is an important attenuator of the surface insolation. Don’t forget though that it increases the atmospheric solar warming.
Just don’t go exaggerating; the reality is significant enough.
Enneagram says:
May 5, 2010 at 2:42 pm
DirkH
We are all doomed, at least statistically. The real question is: Shall we survive statistics?
Statistically speaking, I figure it to be 100% chance that everyone will die…eventually.
There would have to be more than one type of fusion as in a lab is slamming molecules together and in nature it uses rotation for friction and super compression.
“”” Harry Lu says:
May 5, 2010 at 4:54 pm
Ryan N. Maue says:
May 5, 2010 at 4:03 pm
REPLY: If you are talking about straight linear energy transfer, I’d agree. However, I’ve often suspected there is some sort of transistor effect going on between the solar TSI (true TSI, all energy sources, not just visible) and earth’s atmosphere. -A
Leif once responded to a question on TSI that it was TOTAL solar irrradience – all energy is absorbed by the sensor and causes heating which is measured. Not just visible colors but all wavelengths.
It doesnot of course measure magnetic waves, gravity waves or other esoteric energies “””
To be realistic Harry, you need to look at just how much of these exotic wavelength energies are available. Our sun is one of the closest things to a black body radiator that we have available to us; so general BB theory can give us a lot of insight.
Standard curves show that an ideal BB radiator emitss 98% of its total energy at wavelengths between one half of the peak wavelength, and 8 times the peak wavelength; the other 2% being split below and above those ranges.
Taking 0.5 microns as the peak of the solar spectrum (roughly), that gives 1% at lesss than 250 nm and 1% at more that 4.0 microns.
The real sun extraterrestrially does show excessive nearUV spectral emittance near the peak and that is known to change with solar activity.
At ground level, the UV compnent has also been observed to change both seasonally, and at other time scales; providing indirect evidence via the apparent sun’s color temperature, that oznone holes have always been with us; off and on.
The energy outside that 0.5 to 4 x range falls off very rapidly, specially on the short end. At or below 1/4 of the peak wavelength, the relative spectral radiant emittance is 1/10,000 of the peak; and the same level is reached at about 20 times the peak or 10 microns.
So the satellite sensors can collect a wide enough spectrum to give credible values for TSI.
Joe says:
May 6, 2010 at 10:54 am
There would have to be more than one type of fusion as in a lab is slamming molecules together and in nature it uses rotation for friction and super compression.
No, rotation has nothing to do with this. Here is how the Sun’s energy is produced: http://en.wikipedia.org/wiki/Solar_core
Leif Svalgaard
I am just trying to show you that this is someone’s theory. Like the THEORY of the Earths’ core and how the moon slows down the planet.
This would mean that the suns core does not rotate but the carona does, planets do, solar systems do, our core does. I would guess then that gravity must be holding the core together with magnetics.
Rotation can, when created, infused energy and compression into an object. This energy and compression releases slowly and the rotation slows down. Rotation does not carry infinite energy. It was infused to be used up.
Joe
Fusion has been achieved just fine in the laboratory of earth without rotation…. think H bomb. You use a fission reaction to create the heat and pressure to compress H til it over comes electron repulsion. They work. (id assume they use heavy water as the hydrogen source to gain that lil bit o extra mass per H atom.)
Joe says:
May 6, 2010 at 1:22 pm
Like the THEORY of the Earths’ core and how the moon slows down the planet.
This is more than just a theory. It has been measured and agrees with what is expected from theory, which we usually take as a sign that the theory is good.
This would mean that the suns core does not rotate but the corona does, planets do,[…]
the sun’s core does rotate. We know this two ways: 1: we can look into the Sun [like seismology does on Earth when prospecting for oil] and see that it rotates, and 2: rotation causes a slight flattening at the poles [for the Earth that is about 1/300 of the diameter of the Earth] depending on how much mass is rotating how fast. Almost all the Sun’s mass is in the core and the computed flattening matches the flattening actually observed,
Educate yourself by reading the reference that I provided you with and perhaps some of the other references given therein, or come back and ask me for clarification of points you have difficulties with. This is the marvel of a blog like WUWT that ye can ASK and ye shall know.
Stephen Wilde says: (May 6, 2010 at 6:51 am)
“Actually isn’t the Caribbean near the end track for developing hurricanes coming in from West Africa ?”
Only later on in the hurricane season. Earlier, most of the storms originate in the Gulf of Mexico and the Caribbean.
“Thus one would generally on average expect to see weakening in the Caribbean area anyway compared to the cyclogenesis on the way to the Caribbean.”
The Caribbean is usually several degrees warmer than the Atlantic so the storms have a tendency to increase in intensity when the other conditions are right.
“In fact the Caribbean is usually a weak spot in the development track before cyclogenesis reinvigorates if the hurricane gets into the Gulf of Mexico.”
I wouldn’t call it a weak spot. Storms that get close to the islands of Hispaniola and Cuba weaken due to the higher elevations on those islands disrupting wind flow.
Our fear on the west coast of Florida are storms that come out of the western part of the Caribbean, that move northeast between Mexico and Cuba then enter the really warm waters of the Gulf of Mexico off the southwest coast of Florida. When they stay on that track they can slam directly into the west coast of Florida (where I live). Fortunately, not many do this.
While on the subject, I have always wondered why the area of the central west coast of Florida between Tampa Bay and Charlotte Harbor rarely, and I mean rarely, gets hit with storms. Is it possible that rising air from these large bodies of extremely warm water creates a lower pressure than the surrounding area which steers the storms towards them and away from me. In 2004, Hurricance Charlie was moving up the southwest coast of Florida, it’s eye wall very close to shore. When I saw it intensify to a Cat 4 just south of Ft Myers, I headed for the shelter as I live just north of there and less than a mile from the beach. If Charlie stayed on that track I am sure the eye wall would have made a direct pass over my house. But it didn’t stay on that track, at the last minute Charlie veered up Charlotte Harbor towards the center of the state. Path of least resistance? Anyone?
Leif Svalgaard says:
May 6, 2010 at 5:48 pm
Educate yourself by reading the reference that I provided you with and perhaps some of the other references given therein, or come back and ask me for clarification of points you have difficulties with. This is the marvel of a blog like WUWT that ye can ASK and ye shall know.
Thank you Leif.
I do have a bad habit of the hunger of knowledge.
The area of study I am looking into was never really explored and it is quite expansive.
When you take a circle and apply rotation, it becomes a very complex system. Now applying that to an orb is challenging to say the least.
But science has missed a great deal and a great deal is incorrect which makes it that much more harder.
Interesting, thank you.
First time – in many thousands of AGW notes and reports – that I’ve seen UV mentioned.