Friday, 26 September 2014

Side note

Any one like to speculate what this graph shows and where it comes from?

Details and credits later...

Well, I'm disappointed by the lack of interest. It comes from here:
Millennial minimum temperature variations in the Qilian Mountains, China: evidence from tree rings
Y. Zhang1, X. M. Shao1, Z.-Y. Yin1,2, and Y. Wang1
1Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
2Department of Environmental and Ocean Sciences, University of San Diego, San Diego, CA 92110, USA

Abstract. A 1343-year tree-ring chronology was developed from Qilian junipers in the central Qilian Mountains of the northeastern Tibetan Plateau (TP), China. The climatic implications of this chronology were investigated using simple correlation, partial correlation and response function analyses. The chronology was significantly positively correlated with temperature variables prior to and during the growing season, especially with monthly minimum temperature. Minimum temperature anomalies from January to August since AD 670 were then reconstructed based on the tree-ring chronology. The reconstruction explained 58% of the variance in the instrumental temperature records during the calibration period (1960–2012) and captured the variation patterns in minimum temperature at the annual to centennial timescales over the past millennium. The most recent 50 years were the warmest period, while 1690–1880 was the coldest period since AD 670. Comparisons with other temperature series from neighbouring regions and for the Northern Hemisphere as a whole supported the validity of our reconstruction and suggested that it provided a good regional representation of temperature change in the northeastern Tibetan Plateau. The results of wavelet analysis showed the occurrence of significant quasi-periodic patterns at a number of recurring periods (2–4, 40–50, and 90–170 years), which were consistent with those associated with El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and solar activity. The comparison between the reconstructed temperature and the index of tropical volcanic radiative forcing indicated that some cold events recorded by tree rings may be due to the impact of tropical volcanic eruptions.

I'd have thought at least someone would have been interested enough to note that here is yet another Palaeo study, showing yet another 'hockey stick', but absolutely, entirely and unequivocally distinct from previous studies done anywhere, including the USA.

Might some people find this 'inconvenient'?