Ken Stewart, March 2011
Readers familiar with my analysis of the official climate record of Australia may be wondering what has happened since Part 8 posted in July last year.
I have also performed a sort of internal monitoring check on my own results. I have been begging BOM- or anyone- to check my analysis but to no avail. I therefore have gone through every one of the 100 High Quality sites and checked my splices, calculations, and plots, for the third time. (All of these are based on publicly available data from the BOM website.)
I have made some changes to some sites- notably in New South Wales- and reassessed some trend figures in Victoria and Cape Bruny in Tasmania. I have gone back to my original assessment of Bowen in Queensland. A point that needs emphasising here is that anyone going through the data could come up with a slightly different result each time- as the subjective, manual method used by BOM is not reproducible. Another is that many of these sites should not be used at all because of missing or short data, urban influence, or lack of good overlap.
The changes? While I have reduced NSW’s overall warming bias of raw vs BOM’s published figure from 60% to 45%, this has involved a reduction in the average adjustment of only 0.02 degrees C; Victoria’s warming bias of over 140% is unchanged. The Australia-wide average amount of adjustment per site is +0.22 degrees C per 100 years- down from 0.23. The median adjustment is 0.25C (a change of 0.025 down from 0.275C, or one place in the ranked list of stations.) And the Australia wide graph is unchanged, with the difference in trends of 0.25C exactly the same.
Once again, the results speak for themselves: when the results of the homogeneity adjustments are compared with the raw data, there is a discrepancy of over 40%.
My next project is to plot the trends in maxima to 2010, just checking how hot 2010 was. Just to whet your appetite, here’s BOM’s own plot for Tenterfield NSW- I can’t be accused of not doing my sums right or cherry picking.
No, one station does not prove anything, but watch this space.