I’ve obviously been in a quiet blogging patch. My wife and I were visiting our daughter who lives in western Canada.
I’m still amazed and flattered at my inclusion on the New Statesman list. I will post my reflections on this inclusion at some point, but I want to discuss the point more from a sociological than personal point of view. I also want to think about it for a while before commenting.
I spent some time re-visiting Yamal issues in the light of Climategate correspondence. I had hoped that the inquiries would have actually inquired into Yamal. I’ve got quite a bit of pending material on this which I’ll get to some time.
I’ve also spent a fair bit of time on Ljungqvist 2010 (and 2009). I’ve corresponded cordially with Ljungqvist and now have a complete collection of his 2010 proxies – a few of which, interestingly, were downloaded from Climate Audit (e.g. the Esper version of Polar Urals). Ljungqvist sent me a Supplementary Information listing the URLs from which data sets were downloaded, including some data sets in which the website was denoted only by its IP address, rather than its name – the IP address was Climate Audit before the move to wordpress. At this point, my interest is not with the “results”, but with the data. Ljungqvist’s collection includes many paleolimnological proxies, some of which overlap Kaufman et al 2009, but others that are not available elsewhere. Rather than getting too fussed about medieval-modern differentials in one squiggle rather than another, I would like to go a little deeper into the paelolimnological data as a whole – re-examining what, if anything, can be deduced from it. We discussed a number of data sets in connection with Kaufman et al 2009, but there are others that warrant examination.
Ljungqvist also introduced a new speleothem proxy. Speleothems have been playing an increasing role in recent multiproxy collections – Mann et al 2008 has a lot of speleothems in the AD1000 network. There have been interesting speleothem datasets archived at NCDC in the past 18 months – many involving Chinese speleothems, archiving practices for which seem to be much, shall we say, prompter than for speleothems from Raymond Bradley’s NSF-financed unit at the University of Massachusetts or Lonnie Thompson’s NSF-financed ice cores.
I’ve also spent time on McShane and Wyner – unfortunately, more time after submitting our discussion than before. The 93-proxy dataset that they use in their AD1000 reconstruction includes 24 strip bark series and 2 Korttajarvi series (Tiljander) without removing the contaminated segments. So it requires great caution in interpreting their results other than where they are, in effect, only mathematical. While I welcome their interest in the field, I wish that they hadn’t used things like “lasso” that aren’t actually in use in the field.
I also spent some time re-visiting boreholes – the interpretation of which seems very problematic. I’ve taken a look at some pre-inversion measurements in mining areas that I know a bit about and have some work in progress.
Also I noticed some interesting things about accumulation time series in long glacier holes – work in progress on that.
As regular readers know, as interesting as I find the statistical issues of reconstructions, I think that climatescientists spend too much time worrying about multivariate techniques – most of which is lost energy in the absence of adequate statistical theory anyway – and far too little time worrying about the data. A statistical model that encompasses 6-sigma strip bark excursions is not easy to develop, but I don’t see how the field advances without developing such a theory. I had some cordial correspondence with McShane and Wyner, who are very interested in the statistical aspects of the reconstruction projection and will hopefully be interested in these problems as well.
Speaking of which, I’ll also mention another article that discusses statistical aspects of climate reconstructions that, to my great shame, I didn’t attend to when it first came out – Loehle and McCulloch 2008, a situation that I also hope to remedy. I had presumed that this article was simply a corrigendum, but it has a very interesting discussion of “cross-sectional heteroscedasticity” in the context of CPS reconstructions. Hu McCulloch also has an excellent working paper on reconstruction methodology, attention to which is long overdue.