At Burke, in western NSW, Bo M deleted the first 40 years of data because temperatures before 1908 were apparently not recorded in a Stevenson screen, the agreed modern method.
(See Ken’s Kingdom) NASA’s Goddard Institute also adjusts the minima at Amberley up by homogenization with other stations.
But the radius of those stations is nearly 1,000 km.
‘Historical data was homogenised to account for a wide range of non-climate related influences such as the type of instrument used, choice of calibration or enclosure and where it was located.
“All of these elements are subject to change over a period of 100 years, and such non-climate related changes need to be accounted for in the data for reliable analysis and monitoring of trends,’’ BOM said.
This is a station at an airforce base that has no recorded move since 1941, nor had a change in instrumentation.
It is a well-maintained site near a perimeter fence, yet the homogenisation process produces a remarkable transformation of the original records, and rather begs the question of how accurately we know Australian trends at all when the thermometers are seemingly so bad at recording the temperature of an area.Translated: We are careful people, “trust us” Despite Amberley being a good station (as far as anyone can figure) it was adjusted to fit “neighbours” hundreds of kilometers away: ‘BOM said the adjustment to the minimums at Amberley was identified through “neighbour comparisons”.It said the level of confidence was very high because of the large number of stations in the region.Ken Stewart was the first to notice this anomaly and many others when he compared the raw data to the new, adjusted ACORN data set.Jennifer Marohasy picked it up, and investigated it and 30 or so other stations.There’s a suggestion that the changes don’t matter much: ‘It said data from a selection of weather stations underwent a process known as “homogenisation” to correct for anomalies.