Miles : what happened in 1997?
See ACORN Observation Practices (p12) As evident in the maximum temperature chart below, there was a warming at the Miles weather station starting in 1997.
The table below shows maximum and minimum temperatures from 1986 to 2010 (AWS and small screen October 1997) as estimated in the homogenised ACORN 1 and ACORN 2 temperature datasets, and the unadjusted original RAW observations :
The 1987-1996 maximum averages were : ACORN 1 26.99C / ACORN 2 27.37C / RAW 27.31C The 1998-2007 maximum averages were : ACORN 1 27.76C / ACORN 2 28.04C / RAW 27.98C The 1987-1996 minimum averages were : ACORN 1 12.69C / ACORN 2 12.69C / RAW 12.69C The 1998-2007 minimum averages were : ACORN 1 13.00C / ACORN 2 13.00C / RAW 13.03C The original RAW maximum averages increased 0.67C from 1987-1996 to 1998-2007. The ACORN 1 maximum averages increased 0.77C from 1987-1996 to 1998-2007. The ACORN 2 maximum averages increased 0.67C from 1987-1996 to 1998-2007. The original RAW minimum averages increased 0.34C from 1987-1996 to 1998-2007. The ACORN 1 minimum averages increased 0.31C from 1987-1996 to 1998-2007. The ACORN 2 minimum averages increased 0.31C from 1987-1996 to 1998-2007. The BoM's ACORN-SAT station catalogue reads : The current site (42112) is located in a vacant lot on the western edge of the small town of Miles, with no buildings within 30 m. The instrument enclosure contains mown unwatered grass, with natural grass and small trees beyond. History The former site (42023) was located in the town. The screen was reported in September 1929 as having numerous missing louvres. It became somewhat overgrown from about 1990 onwards, but continued to measure temperatures until 2005. Rainfall continues to be measured at this site. The current site has been operating since July 1997, about 300 m west-northwest of the previous site. There was a significant Miles rainfall decline from 1987-1996 to 1998-2007 (annual average 619.4mm > 554.6mm). After the AWS and small Stevenson screen were installed in 1997, average RAW maxima increased 0.67C from 1987-1996 to 1998-2007 and average minima increased 0.34C. The maxima increase may be due to reduced rainfall but minima would normally decrease as a result of less rainfall due to reduced nighttime cloud cover.
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