Jennifer Marohasy had an interesting post this week on further explanations by the Bureau for their weird adjustments at Rutherglen. I was particularly interested in this graphic, which is Chart 3 on the Bureau’s station adjustment summary for Rutherglen. http://www.bom.gov.au/climate/change/acorn-sat/documents/station-adjustment-summary-Rutherglen.pdf
The Bureau is comparing Rutherglen’s raw minima with the adjusted data from Wagga Wagga, Deniliquin, and Kerang. Three questions immediately spring to mind: 1. As Dr Marohasy points out, what is the Bureau doing comparing raw with adjusted data? Of course they’re going to have different trends! 2. Why is Kerang shown, when Kerang is NOT included as a neighbour station used to adjust Rutherglen? And 3. What difference does this make?
Time for a reality check.
This graph compares like with like: raw minima for Rutherglen and the same neighbours. Note that only Kerang is warming, and Wagga Wagga is flat, but Deniliquin and Rutherglen are cooling.
This graph again compares like with like, the same stations but with adjusted data.
You might think that this shows Rutherglen is now homogenised with the others correctly. However, when we examine the differences in anomalies from the 1961-1990 means between Rutherglen and the others, we get this:
They still got it wrong! The trend in differences should be close to zero. Rutherglen’s adjusted record is warming too fast (+0.5C per 100 years) relative to the three neighbours used by the BOM in their explanation.
And note that since 1974, Rutherglen’s minima have been cooling relative to the others. Perhaps that cooling they corrected for was real after all?
Even if Rutherglen needs to be adjusted; even if these three sites are adjusted correctly; even if Kerang is one of the stations used by the Bureau to adjust Rutherglen- the adjustments at Rutherglen are over cooked.
The “scientists” in charge of the climate change department in the Bureau deserve all the ridicule they get.
More than that- they are not to be trusted with the nation’s climate history. We don’t trust their data; we don’t trust their methods; we don’t trust their results; and we don’t trust their motives.