I would like to think that I would recognise a graph of the data from one of my paper. Perhaps that is optimistic; I’ve not looked at some of my papers for years. Still, the graphs of oxygen isotopes of two species of forams from Murray Canyon reproduced in a new paper by Soon et al looked weird.
More negative values of δ18O in foram tests are associated with warmer water temperatures, so by convention the data are inverted when plotted so negative values, warmer waters, are uppermost. Soon et al had plotted it so positive values, cooler temperatures, are uppermost.
Soon et al are using wavelet analyses to test for “solar-linked climatic variation on centennial and millennial timescales”, with a new multiple cross-wavelet transform. A the usual cross-wavelet transform looks for common power and phase relationships between two proxy records, Soon et al have extended this to consider multiple proxies simultaneously.
Since Soon et al are interested in phase relationships, the orientation of the data matter – a proxy and its inverted self are anti-phased. If Soon et al had arranged all proxies so that cool was up, everything would be fine. But the sea surface temperature record from Stott et al (2004) are plotted warm up.
It is not possible to eyeball the data in Soon et al to see if the reported phase relationships are credible, with or without inverted proxies, as the proxy records are all plotted on their own age scale, preventing comparison.
Of course it is possible that this is just a plotting error, and that the analyses have been done correctly, but there is nothing in the text to suggest this. Soon has a history of awful papers; I’m not inclined to trust this one – there is plenty more that could be questioned.
Soon et al. 2014: A review of Holocene solar-linked climatic variation on centennial to millennial timescales: Physical processes, interpretative frameworks and a new multiple cross-wavelet transform algorithm. Earth-Science Reviews, 134, 1–15