One of the critical issues in Emanuel 2005 (and presumably for other like studies) is how measurement inhomogeneity is dealt with. Emanuel relies on Landsea 1993 for a procedure to downward adjust pre-1970 wind speeds. However, prior to Emanuel’s article, Landsea – who seems vastly more authoritative than Emanuel on hurricane data – had pointed out further inhomogeneities between 1991 and present-day measurements, requiring the upward adjustment of data from the 1980s and 1970s. Indeed, his response to Emanuel raises the issue of whether the need is to adjust 1970-1990 data upwards rather than adjust pre-1970 data downwards.
It is now understood to be physically reasonable that the intensity of hurricanes in the 1970s through to the early 1990s was underestimated, rather than the 1940s and 1960s being overestimated.
It seems clear to me that every hurricane measurement needs to have the estimation method attached to it. For Emanuel to draw lurid trend conclusions with such weak analysis of homogeneity is all too typical of climate science. Continue reading →
Mann and Emanuel 2006 presents an interesting alliance of Emanuel with Michael "I am not a statistician" Mann to carry out calculations purportedly "using a formal statistical analysis to separate the estimated influences of anthropogenic climate change from possible natural cyclical influences". It will come as little surprise to readers of this blog that there appears to some hair on this particular article. Here’s something that I noticed in a first read. Continue reading →
Emanuel 2005 stated:
The annual average storm peak wind speed summed over the North Atlantic and eastern and western North Pacific has also increased during this period, by about 50%.
Once again, I can’t reproduce this result. Here are my calculations. Continue reading →
Emanuel 2005 stated:
The accumulated annual duration of storms in the North Atlantic and western North Pacific has indeed increased by roughly 60% since 1949, though this may partially reflect changes in reporting practices, as discussed in Methods.
Speaking of “rudimentary statistics”, this seems like a rudimentary statistical statement. But there are wheels within wheels. Continue reading →
A couple of days ago, I posted up my attempt to replicate Emanuel 2005 Figure 1 (Atlantic PDI) and today post up a similar exercise on W Pacific PDI. While most hurricane discussion is focussed on the Atlantic, the PDI in the W Pacific is about 5 times larger. Emanuel said:
I maintain that current levels of tropical storminess are unprecedented in the historical record and that a global-warming signal is now emerging in records of hurricane activity This is especially evident when one looks at global activity and not just the 12% of storms that occur in the Atlantic.
Continue reading →
Willis writes: I wanted to see if there was acceleration in the TOPEX sea level record. I have looked all over the web to find either the data used to create the following image of the sea level rise as measured by the TOPEX satellite, available here, or some estimate of any acceleration that might be present in the trend. I could find neither. Here’s the record cited above:
Fig. 1 Original graph of the change in sea level rise. Note that the trend is estimated to the nearest hundredth of a mm per year.
Being unable to find the data, I resorted to my usual technique “¢’¬? digitize it myself. This was difficult, because they used large colored circles for the data points, so it was hard to decipher the graph. As this procedure may be of interest to readers, here’s what I did. Continue reading →
Hot off the press this week is a study on foraminera over the last millennium in the Indo-Pacific Warm Pool – something that you’d think would be relevant to Hansen’s attempts to splice modern instrumental records to core tops ending in the Holocene Optimum. Newton et al 2006 have the following abstract: Continue reading →
Interesting presentation by Bill Gray posted up here . I’ve just scanned through it but I’m sure that it will cause much controversy. Please also consider the critique of Bill Gray at realclimate here . The only areas that I have personally examined data and methods are for proxy data, where obviously I feel that the Hockey Team has used slipshod methods. I do not endorse anything in Gray’s paper and obviously many scientists feel that Gray’s methods are also slipshod. It is beyond my resources to examine everything in the world, though I’m looking a little bit at hurricane data. I’d be happy to post any critical analyses of Gray’s paper from anyone that’s looked at it in detail.
I’m in the process of trying to replicate some of the hurricane papers. Obviously this is new territory for me – so forgive me if I’m going over old ground. Emanuel Figure 1 states in its caption that "total Atlantic hurricane power dissipation has more than doubled in the past 30 yr" and David Stockwell’s query about this, in part, stimulated the recent discussion on this blog. I’ve collated hurricane track information from original sources bringing the data set pretty much up to today. Lots of interesting details when you look closely. Some parts of the debate involving Landsea and Emanuel seem to have been going on for over 20 years, long before the issue became prominent. Continue reading →
I’ve collated some hurricane track data in flat text files so that they are more usable (at least for me) and have posted up the working files since there seems to be interest in this data. I’m also posting up some notes on fiddly format issues while they are fresh in mind. Continue reading →
Climate Audit 
