Hey All,
I've been studying this since 2005, when Dr. Emmanuel first worked on the paper with Dr. Curry WRT the trend in satellite indicated hurricane strength, 8 years ago. No matter, what Dr. Landsea or Dr. Gray who are/were professionals observed (that land crossing storm severity measurements did not correspond to the theory); yet, the folks at NASA took the Hurricane paper to be fact. Now we are seeing this same measure being trotted out as fact wrt general circulation, when once again, I think we are not addressing real measures or establishing what is really happening. The controversary appears to be a case of statistics measured over time without establishing "cause and effect", other than a broad sweeping handwave at AGW.
So what are the facts behind the statistics. Dr. Emmanuel looked over the satellite images and determined that wind speeds seemed to be higher. The allusion being if wind field speeds are higher then the pressures are lower and the storm more powerful. What Dr. Emmanuel did not account for was the difference in the cloud deck altitudes and ground measurements differences. These were shown to be very different (compared to the standard calculated values).
The recent 2012 Hurricane Season storms, when analyzed with CloudSat or Colypso and TRMM, suggested a lower surface wind even for lower then average air pressures. (For instance when looking at a cross section of the recent Storm Sandy and two other storms last year, Leslie and one other I can't recall at this time, both the est. sea surface windspeeds and elevated satellite wind speeds seemed to not match up well. When a Recon flight was used to take measures, close to shore sea buoys, there was also a disconnect to the old calculated surface speeds.) With the unusual weather patterns, rife with stalled tropical storms, we were able to study the dynamics a bit more intently. (Though the fact that few of storms developed a clear eyewall and classic pattern, may suggest the data is not necessarily representative...)
The point is, rather then calculate or attempt to model data, what is the measured data actually telling us, other then we need a better measurement system. (Hence as Baz suggested last year, having long term unmanned drones on station is a good start.) Generally, what I see is there are two factors at work. The first has to do with more stagnant wave patterns. These are generally driven by one of two causes, either a wild wander of the Northern Jet Stream forcing a more cross zonal progression of weather fronts, or more cases of cut-off weather systems. In essence, there is your lesser storm count value.
So what about severity, the longer a storm sits in one place, (or warmer the UL air parcel becomes, (for the classic hurricane hunter, the cooler the sea water, due to upwelling, though the scope/area seems limited to little more then about 10 times the dia. of the eyewall.)), hence the weaker a cyclonic grows and (by concentrating cold UL air), the stronger an anti-cyclonic grows. Build up a series of strong down drafts from higher altitudes to create strong anti-cyclonic cycles and as long as the Jet Stream circulation does not breakdown, an increase in perimeter convection caused by warmer, compressed outflow mixing with increased surface specific humidity, should create more powerful cyclonics. Until it reaches a point where every cyclonic wave becomes a major storm. In short high stability at one center should result in much lower stability at another, inverse center.
http://www.scienceda...30225153128.htm
(In a semi-closed system you cannot have an increase in one pattern without a corresponding change in the opposing pattern (wrt strength). In this case the majority of the heat energy input to the UL is either decreasing or the radiated output is increasing (expansion of radiating surface or redirected circulation). This then begs the question how the change in patterns are driven by the change in energy outflow? So my first question is what is causing larger and colder UL air parcels, which are causing expansive High Pressure systems that seem to hang around for months...? (wrt lesser wave counts))
In short, until we start addressing the changes in patterns we can talk about the statistics and find it means nothing, it simply marks time. Now, if we can in this venue, I think it might be worthwhile to look at some of the papers that discuss changes in convection, inversion layers (wet/dry adiabatic transition altitudes), air pressure, specific humidity and CCN. In this way, if we can tie in the changes in global circulation, we can start addressing weather and the changes in its patterns reasonably. As for this article it may be more appropriate in climate change as it is addressing climatic changes; however, that's up to Baz.
As to the significance of this media blurb, it sadly appears to mean little other then apparently restates the obvious/expected. The question is why trot this type of story out unless the intent is to say, "see we told you!". Sorry, I would hire my scientists to tell me why, not to restate the obvious...
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