Vostok ice core, part 2
See part 1 if you haven’t.
Seemed a good test to see if I could reproduce the temperature vs. CO2 lead lag result but using signal processing, data resampling. Turns out the CO2 data is even worse than the isotope ratio temperature data, fewer data points and sampled at different dates.
Easy. I applied identical processing to both datasets and then figured out how to time shift one of them. To my surprise there is a very high correlation, r2=0.82, at least given the preprocessing used. The quick and dirty way to do the time shift was apply an offset at the decimate stage, simply picks off data at a different point. (this is valid)
If I have done this right it is about 1,500 years for best fit of rise and fall. I then aligned the datasets and plotted (Y axis reacaled and offset CO2 by hand so the data roughly matches on one scale) for an eyeball.
Time co-incident plot of temperature and CO2
There is obviously a lot going on but there it is visibly on one plot.
A net dig shows a work by Jo Nova (know the name, no idea who she is)
http://joannenova.com.au/global-warming/ice-core-graph/
That says 800 years and seems to cite others.
Ref
http://www.ncdc.noaa.gov/paleo/metadata/noaa-icecore-2453.html
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/co2nat.txt
