Doug Nychka’s fields package in R is really excellent. Among its nice functions is a command world() that draws an outline of the continents. I wrote him today inquiring whether there was an option in which land could be colored. Unfortunately there wasn’t. However by the end of the day, there was. Doug sent me […]
I then compared verification statistics for the different reconstructions as shown below. OLS yielded much the “best” fit in the calibration period, but the worst fit in the verification period. If OLS is equivalent to ICE, it actually finds the best fit (minimizes calibration residuals), and in proxy-temperature case makes the most obvious overfit. Let […]
I’ve already received my first condescending comments from the dendro world about the mysteries of standardization. Just to pre-empt some further pontification presuming that I know nothing about these mysteries, I’m posting up some notes that I wrote in 2004 on standardization – which was what I would have been working on had people just […]
Mission Impossible Team, here’s your assignment today. Unfortunately you failed your last assignment: replicating Mann’s claimed correlations. But that probably was impossible. Today your assignment is probably possible, but is a dangerous expedition into the dark underground – into the terrifying world of Mannian RegEM. Courage and perseverance will be required. You may not return […]
You may recall the post earlier this year where the USHCN official climate station with the largest positive trend in the USA turned out to be located in a parking lot at the University of Arizona in Tucson. See below: Click picture to see image gallery at surfacestations.org The GISS surface temperature plot for Tucson: […]
A couple of days ago, I received the Almagre measurement data from the excellent dendrochronological lab at the Univesity of Guelph. I’ve posted the measurement data online in two files (as I received them): crossdated and uncrossdated. There are 41 cores that have been crossdated and 20 cores are not crossdated. These files are as […]
Judith Curry and JEG have expressed an interest in talking about Mann et al 2007, Robustness of proxy-based climate field reconstruction methods, JGR pdf. This is successor article to Mann et al, 2005, Testing the Fidelity of Methods Used in Proxy-Based Reconstructions of Past Climate, pdf. Looking past the annoying and amusing faults, here are some […]
Mann et al 2007 is a new RegEM version, replacing the RegEM calculations of Rutherford et al 2005. The logic is not entirely self-contained and so I re-visited some of our previous comments on Rutherford et al here here here here . I’m going to reprise two issues today: Collation Errors, a small but amusing […]
Ross McKitrick writes: First, on page 15, they say: This result (as well as the separate study by Wahl and Ammann [2007]) thus refutes the previously made claim by MM05 that the features of the MBH98 reconstruction are somehow an artifact arising from the use of PC summaries to represent proxy data. Well, if we […]
Here’s an assignment for JEG’s hockey stick class. Try to replicate the reported proxy-gridcell temperature correlations reported in Mann et al 2007 SI. The table showing correlations between 112 proxies (the AD1820 network presumably) and gridcell temperature are shown in column 5 of the spreadsheet here. Data for the 112 proxies in the AD1820 proxy […]
Climate Audit 