http://www.realclimate.org/index.php/archives/2007/03/hurricane-heat/

1 Mar 2007
Hurricane Heat
Filed under:
  a.. Climate Science
  b.. Hurricanes
- gavin @ 5:52 pm - () () ()
The big problem with much of the discussions about trends in hurricane 
activity is that the databases that everyone is working from are known to 
have significant inhomogeneities due to changes in observing practice and 
technology over the years. So it's not surprising that a new re-analysis 
(Kossin et al, published yesterday) has been generating significant interest 
and controversy among the hurricane research community (see e.g. Prometheus 
or Chris Mooney). However, rather than this study being taken for what it 
is - a preliminary and useful attempt to make homogeneous a part of the data 
(1983 to 2005) - it is unfortunately being treated as if it was the 
definitive last word. We've often made the point that single papers are not 
generally the breakthroughs that are sometimes implied in press releases or 
commentary sites and this case is a good example of that.


Kossin et al develop an algorithm based on North Atlantic data that can be 
theoretically used with the coarsest data available from the earlier parts 
of the record and in more remote regions. While the technique works well in 
the North Atlantic (picking up almost all of the storms seen in the standard 
data), it doesn't work as well in other basins - possibly because the 
characteristics of tropical cyclones are not universal, or because the 
coarse early remote sensing data are still not sufficient. The poorer 
performance in the other basins is surely a reason to anticipate that 
further work will be necessary to refine these estimates, and should serve 
as a caution to those wanting definitive conclusions.

How does this fit in with some of the previous work? Well, it confirms the 
large trend in the North Atlantic (seen in Emanuel, 2005), but doesn't show 
significant trends in the other basins (from 1983). This isn't directly 
comparable with Webster et al (2005) though, since their trends start in the 
1970s, and the shortness of the new reanalysis (only 23 years) emphasizes 
interannual and decadal variability associated with e.g. El Nino. The Kossin 
et al study is therefore unlikely to shed much light on the potential global 
warming/hurricane intensity link.

In summary, read the papers and the comments but don't believe the hype.

We'll start off the discussion with a few comments we have already received 
on the provocative study: