New Nature Study Finds Poleward Migration of Maximum Hurricane Intensity

[LocoAko]

Original study by James P. Kossin, Kerry A. Emanuel & Gabriel A. Vecchi: http://www.nature.com/nature/journal/v509/n7500/full/nature13278.html#access (unfortunately not free)

Abstract (emphasis mine):

 

Temporally inconsistent and potentially unreliable global historical data hinder the detection of trends in tropical cyclone activity. This limits our confidence in evaluating proposed linkages between observed trends in tropical cyclones and in the environment. Here we mitigate this difficulty by focusing on a metric that is comparatively insensitive to past data uncertainty, and identify a pronounced poleward migration in the average latitude at which tropical cyclones have achieved their lifetime-maximum intensity over the past 30 years. The poleward trends are evident in the global historical data in both the Northern and the Southern hemispheres, with rates of 53 and 62 kilometres per decade, respectively, and are statistically significant. When considered together, the trends in each hemisphere depict a global-average migration of tropical cyclone activity away from the tropics at a rate of about one degree of latitude per decade, which lies within the range of estimates of the observed expansion of the tropics over the same period6. The global migration remains evident and statistically significant under a formal data homogenization procedure3, and is unlikely to be a data artefact. The migration away from the tropics is apparently linked to marked changes in the mean meridional structure of environmental vertical wind shear and potential intensity, and can plausibly be linked to tropical expansion, which is thought to have anthropogenic contributions.

Article about study (from Mashable, so take it FWIW, but it has quotes by the lead author James Kossin, Chris Landsea, Hugh Willoughby, etc.): http://mashable.com/2014/05/14/migrating-hurricane-intensity-tropics-expand-global-warming/

Looks like pretty interesting work -- I hope to be able to get it on my work domain. Clever way around the sampling issue for the historical record of tropical cyclones, and perhaps one of the first works to isolate an effect like this only to find it to be statistically significant. Great stuff.

[Msalgado]

If you can't get it on your work domain let me know.  I can email you a copy.

[LocoAko]

If you can't get it on your work domain let me know.  I can email you a copy.

Was able to get it - thanks!

[WXheights]

Wasn't Landsea a "denier" . Hmmm before you know it you'll see JB sign off on one of these

[ORH_wxman]

Wasn't Landsea a "denier" . Hmmm before you know it you'll see JB sign off on one of these

 

 

Where would you get that idea?

[WXheights]

Where would you get that idea?

Opposite Kerry Emanuel on past studies relating to AGW and TC 's

[ORH_wxman]

Opposite Kerry Emanuel on past studies relating to AGW and TC 's

 

 

How does that make Landsea a "denier"?

 

He found no link to TC damages or frequency due to AGW (or any other factor). Emmanual's studies have indicated that the peak intensity could increase by about 1-3% in the future due to warming.

[Msalgado]

Wasn't Landsea a "denier" . Hmmm before you know it you'll see JB sign off on one of these

 

FYI, the paper doesn't attribute the change to climate change.