Homogenised temperatures, and planning for bushfires

Most peculiarly, according to the Bureau’s own policy, in accordance with world’s best practice as recommended by the World Meteorological Organisation, any significant site relocation should result in a new site number. Yet Rutherglen has always been referred to by a single station number: 082039. This is in contrast, for example, to the nearby location of Deniliquin that was number 074128 when the weather station was at the post office, and number 074258 when it was moved to the airport.

Putting all of this aside, is it reasonable to assume that moving a weather station between paddocks will create a difference of 5.4 °C for 13 January 1939 between the measured and the adjusted values? No, it is not.

Back in 2014, then Prime Minister Tony Abbott was right to suggest an inquiry into the Bureau of Meteorology and this revisionist approach to the historical temperature record.  Greg Hunt, Environment Minister at the time, apparently “killed” the idea during these discussions in cabinet claiming confidence in the Bureau by the Australian public was paramount – especially so we (the public) would heed bushfire warning. But how reliable are these warning – and exactly which historical record are they based on?

Postscript
More information on temperature trends at Rutherglen is detailed in Marohasy, J., Temperature change at Rutherglen in south-east Australia, New Climate (2016).
The difference of 5.4 °C between the adjusted and raw values on 13 January 1939 can be verified by scrutinising the ACORN-SAT versus CDO/raw daily data for Rutherglen available at the Bureau of Meteorology website online. Specifically the ACORN-SAT TMax for Rutherglen versus the raw TMax for Rutherglen – scroll to 13 January 1939.