Email 3499: Michael Mann provides some code, cautions "don't pass it along where it may get into the hands of the wrong people"; admits something "a bit odd" that "increases the amplitude of the reconstruction everywhere by the factor 1.29"

Email 3499

I've attached a cleaned-up and commented version of the matlab code that I wrote for doing the Mann and Jones (2003) composites. I did this knowing that Phil and I are likely to have to respond to more crap criticisms from the idiots in the near future, so best to clean up the code and provide to some of my close colleagues in case they want to test it, etc. Please feel free to use this code for your own internal purposes, but don't pass it along where it may get into the hands of the wrong people. In the process of trying to clean it up, I realized I had something a bit odd, not necessarily wrong, but it makes a small difference. It seems that I used the 'long' NH instrumental series back to 1753 that we calculated in the following paper: * Mann, M.E., Rutherford, S., Bradley, R.S., Hughes, M.K., Keimig, F.T., [1]Optimal Surface Temperature Reconstructions using Terrestrial Borehole Data, Journal of Geophysical Research, 108 (D7), 4203, doi: 10.1029/2002JD002532, 2003.

(based on the sparse available long instrumental records) to set the scale for the decadal standard deviation of the proxy composite. Not sure why I used this, rather than using the CRU NH record back to 1856 for this purpose. It looks like I had two similarly named series floating around in the code, and used perhaps the less preferable one for setting the scale. Turns it, this has the net effect of decreasing the amplitude of the NH reconstruction by a factor of 0.11/0.14 = 1.29. This may explain part of what perplexed Gabi when she was comparing w/ the instrumental series. I've attached the version of the reconstruction where the NH is scaled by the CRU NH record instead, as well as the Matlab code which you're welcome to try to use yourself and play around with. Basically, this increases the amplitude of the reconstruction everywhere by the factor 1.29. Perhaps this is more in line w/ what Gabi was estimating (Gabi?)  [Michael Mann]