ACORN 2.2 influence on Tasmania temperature trendsAustralia New South Wales Northern Territory Queensland South Australia Victoria Western Australia
There are seven ACORN stations in Tasmania. This page analyses the daily temperatures at all seven weather stations and averages the three with a start year of 1910 to ensure a uniform timescale. The other four excluded stations have temperature recordings starting in years after 1910, the most recent being Grove with a start year of 1955. The three long-term weather stations analysed on this page (with a start year of 1910) had a 1910-1964 average maximum of 16.79C in ACORN 2.1 and a 1910-1964 average maximum of 16.68C in ACORN 2.2 - a 0.11C cooling of historic maxima. The three long-term weather stations had a 1910-1964 average minimum of 8.31C in ACORN 2.1 and a 1910-1964 average minimum of 8.31C in ACORN 2.2 - meaning ACORN 2.2 has not altered the historic minima of ACORN 2.1. Daily temperatures in ACORN 2.2 and RAW have been annualised, and below are charts showing the difference between the ACORN 2.2 homogenised dataset when compared to original raw annual temperatures. This analysis only allows the inclusion of years within which there were no months with less than 15 days of recorded temperatures, as is the ACORN protocol. Three Tasmanian stations begin in 1910 and end in 2020 in ACORN 2.2 and RAW - Eddystone Point, Launceston and Low Head. The first charts below show maximum and minimum temperature trends at these three stations with associated data. Excel files at the bottom of each station chart and data summary can be downloaded to compare how the ACORN 2.2 algorithms influence daily, monthly and annual temperatures at all seven sites since 1910.
1910-1964 - ACORN 2.2 16.68C / raw 16.75C 1965-2020 - ACORN 2.2 17.24C / raw 17.16C ACORN 2.2 warmed 0.56C / raw warmed 0.41C Average change per decade : ACORN 2.2 0.09C / raw 0.07C Tasmania 2000-2020 - ACORN 2.2 17.57C / raw 17.54C The first decade, 1910-1919, averaged 16.84C in ACORN 2.2 and 17.11C in raw The final decade, 2011-2020, averaged 17.64C in ACORN 2.2 and 17.69C in raw 1961-90 - ACORN 2.2 - 17.04C / raw 16.88C Download Excel spreadsheet for three Tasmanian weather stations in ACORN 1, ACORN 2.2 and RAW
1910-1964 - ACORN 2.2 8.31C / raw 8.73C 1965-2020 - ACORN 2.2 8.94C / raw 8.92C ACORN 2.2 warmed 0.63C / raw warmed 0.19C Average change per decade : ACORN 2.2 0.09C / raw 0.03C Tasmania 2000-2020 - ACORN 2.2 9.20C / raw 9.20C The first decade, 1910-1919, averaged 8.40C in ACORN 2.2 and 8.99C in raw The final decade, 2011-2020, averaged 9.25C in ACORN 2.2 and 9.25C in raw 1961-90 - ACORN 2.2 - 8.84C / raw 8.85C Download Excel spreadsheet for three Tasmanian weather stations in ACORN 1 and ACORN 2.2 and RAW Station menu Butlers Gorge, Cape Bruny, Eddystone Point, Grove, Hobart, Launceston, Low Head Butlers Gorge
1945-1982 - ACORN 2.2 12.36C / raw 12.70C 1983-2020 - ACORN 2.2 13.24C / raw 13.24C ACORN 2.2 warmed 0.88C / raw warmed 0.54C Average change per decade : ACORN 2.2 0.28C / raw 0.20C Butlers Gorge 2000-2020 - ACORN 2.2 13.47C / raw 13.42C 1961-90 - ACORN 2.2 12.79C / raw 12.96C Pre 1972 .0 F rounding ACORN 2.2 - 17.19% / raw - 87.75% Post 1972 .0 C rounding ACORN 2.2 - 9.62% / raw - 29.42% The first decade, 1945-1954, averaged 11.69C in ACORN 2.2 and 12.24C in raw The final decade, 2011-2020, averaged 13.54C in ACORN 2.2 and 13.54C in raw ACORN catalogue: The original site at Butlers Gorge (also numbered 096003) operated from 1944 at the Hydro-Electric Commission settlement. The site appears to have been unchanged during the 1944–1993 period. In the early years of observations a HEC-pattern screen (single-louvred and lower than a Bureau standard screen) was used; this was replaced with a Bureau standard screen some time between 1973 and 1976. Observations appear to have been made at non-standard times (earlier than 9 am) on occasions. The settlement was abandoned, with all buildings removed, by 1969. Observations continued until October 1993. The current site is an automatic weather station which was installed about 150 m east of the previous site. It commenced observations in May 2008. Data from Lake St Clair (096071) was used in the 1993–2008 period, with the overlaps at both ends of this period used to merge the datasets. Lake St Clair is approximately 20 km north of Butlers Gorge but the overlap data indicates that temperature differences between the two locations are minimal. The site is over marshy tussock grass about 200 m southeast of the visitors’ centre. 1998-2007 raw max averaged 13.37C and post AWS 2009-2018 averaged 13.57C Butlers Gorge max Excel spreadsheets
1945-1982 - ACORN 2.2 3.10C / raw 2.93C 1983-2020 - ACORN 2.2 3.17C / raw 2.93C ACORN 2.2 warmed 0.07C / raw unchanged Average change per decade : ACORN 2.2 0.11C / raw 0.12C Butlers Gorge 2000-2020 - ACORN 2.2 3.27C / raw 3.15C 1961-90 - ACORN 2.2 3.26C / raw 2.91C Pre 1972 .0 F rounding ACORN 2.2 - 19.29% / raw - 86.45% Post 1972 .0 C rounding ACORN 2.2 - 10.12% / raw - 28.41% The first decade, 1945-1954, averaged 2.65C in ACORN 2.2 and 2.57C in raw The final decade, 2011-2020, averaged 3.39C in ACORN 2.2 and 3.39C in raw 1998-2007 raw min averaged 2.94C and post AWS 2009-2018 averaged 3.41C Butlers Gorge min Excel spreadsheets Cape Bruny
1923-1971 - ACORN 2.2 15.22C / raw 14.51C 1972-2020 - ACORN 2.2 15.87C / raw 15.59C ACORN 2.2 warmed 0.65C / raw warmed 1.08C Average change per decade : ACORN 2.2 0.15C / raw 0.22C Cape Bruny 2000-2020 - ACORN 2.2 16.15C / raw 16.11C 1961-90 - ACORN 2.2 15.71C / raw 15.14C Pre 1972 .0 F rounding ACORN 2.2 - 20.50% / raw - 74.42% Post 1972 .0 C rounding ACORN 2.2 - 10.58% / raw - 19.88% The first decade, 1923-1932, averaged 15.00C in ACORN 2.2 and 14.44C in raw The final decade, 2011-2020, averaged 16.32C in ACORN 2.2 and 16.33C in raw ACORN catalogue: The site appears to have been close to its current location before a move in April 1939. It also moved on 13 November 1961, and 45 m east in March 1969. An automatic weather station (094198) has been operating since 1997 at Cape Bruny. This is expected eventually to supersede the current site. It is about 50 m west of the current site, close to the 1961–1969 location of the manual site, but is in a more exposed location on top of the ridge. This exposure has clearly reduced rainfall readings but impacts on temperature are less clear. 94010 1987-1996 average max 15.13C vs 94198 AWS 1998-2007 (50 metres west) average max 15.47C Cape Bruny presents an interesting comparison of an Automatic Weather Station and a manual Stevenson screen both observing daily temperatures over 20 years. The Cape Bruny analysis raises questions about the warming influence of AWS temperature readings in all latitudes across Australia. Cape Bruny max Excel spreadsheets
1923-1971 - ACORN 2.2 8.06C / raw 8.44C 1972-2020 - ACORN 2.2 9.03C / raw 9.18C ACORN 2.2 warmed 0.97C / raw warmed 0.74C Average change per decade : ACORN 2.2 0.16C / raw 0.12C Cape Bruny 2000-2020 - ACORN 2.2 9.28C / raw 9.31C 1961-90 - ACORN 2.2 8.69C / raw 9.03C Pre 1972 .0 F rounding ACORN 2.2 - 22.92% / raw - 74.05% Post 1972 .0 C rounding ACORN 2.2 - 10.21% / raw - 20.96% The first decade, 1924-1933, averaged 7.97C in ACORN 2.2 and 8.34C in raw The final decade, 2011-2020, averaged 9.35C in ACORN 2.2 and 9.36C in raw 94010 1987-1996 average min 8.88C vs 94198 AWS 1998-2007 (50 metres west) average max 9.48C Cape Bruny min Excel spreadsheets Eddystone Point
1910-1965 - ACORN 2.2 17.28C / raw 16.64C 1966-2020 - ACORN 2.2 17.92C / raw 17.36C ACORN 2.2 warmed 0.64C / raw warmed 0.72C Average change per decade : ACORN 2.2 0.07C / raw 0.13C Eddystone Point 2000-2020 - ACORN 2.2 18.22C / raw 18.21C 1961-90 - ACORN 2.2 17.67C / raw 16.76C Pre 1972 .0 F rounding ACORN 2.2 - 17.77% / raw - 67.46% Post 1972 .0 C rounding ACORN 2.2 - 15.64% / raw - 29.23% The first decade, 1910-1919, averaged 17.72C in ACORN 2.2 and 17.09C in raw The final decade, 2011-2020, averaged 18.34C in ACORN 2.2 and 18.34C in raw ACORN catalogue: There is little documentation on the site prior to the 1990s, but it is believed that there were no significant site moves between 1908 and 1996. An automatic weather station was installed in late 1996, with an associated site move about 70 m southeast. Parallel observations were carried out with the former site (using the station number 092115), but some observations from the new site were incorrectly recorded against the comparison number, making it impracticable to use the parallel observations to assess the impact of the move. Assuming the AWS was operational from 1996, 1986-1995 raw max averaged 17.09C and post AWS 1997-2006 averaged 17.88C Eddystone Point max Excel spreadsheets
1910-1965 - ACORN 2.2 9.93C / raw 9.77C 1966-2020 - ACORN 2.2 10.56C / raw 10.56C ACORN 2.2 warmed 0.63C / raw warmed 0.79C Average change per decade : ACORN 2.2 0.08C / raw 0.10C Eddystone Point 2000-2020 - ACORN 2.2 10.71C / raw 10.71C 1961-90 - ACORN 2.2 10.38C / raw 10.41C Pre 1972 .0 F rounding ACORN 2.2 - 16.66% / raw - 67.62% Post 1972 .0 C rounding ACORN 2.2 - 23.45% / raw - 31.72% The first decade, 1910-1919, averaged 9.96C in ACORN 2.2 and 9.80C in raw The final decade, 2011-2020, averaged 10.77C in ACORN 2.2 and 10.77C in raw Assuming the AWS was operational from 1996, 1986-1995 raw min averaged 10.37C and post AWS 1997-2006 averaged 10.60C Eddystone Point min Excel spreadsheets Grove
1955-1987 - ACORN 2.2 17.37C / raw 16.85C 1988-2020 - ACORN 2.2 17.59C / raw 17.57C ACORN 2.2 warmed 0.22C / raw warmed 0.72C Average change per decade : ACORN 2.2 0.09C / raw 0.19C Grove 2000-2020 - ACORN 2.2 17.65C / raw 17.66C 1961-90 - ACORN 2.2 17.49C / raw 16.99C Pre 1972 .0 F rounding ACORN 2.2 - 17.33% / raw - 44.03% Post 1972 .0 C rounding ACORN 2.2 - 9.74% / raw - 12.15% The first decade, 1955-1964, averaged 17.28C in ACORN 2.2 and 16.74C in raw The final decade, 2011-2020, averaged 17.74C in ACORN 2.2 and 17.74C in raw ACORN catalogue: The original site (094069) was also on the Research Station grounds and began operating in 1952. New buildings had been built approximately 15 m away from the site at some point between 1966 and 1985, most likely after 1980. The instruments were relocated 100 m west on 17 January 1990 in anticipation of a new building which was never constructed. The site closed in 2010. The current automatic weather station was established 190 m southwest of the previous site, and has been operating since June 2004. 94069 overlap with 94220 16 June 2004 to 9 February 2010 : 94069 17.43C / 94220 17.42C 1994-2003 raw max averaged 17.46C and post AWS 2005-2014 averaged 17.62C
1955-1987 - ACORN 2.2 5.19C / raw 5.79C 1988-2020 - ACORN 2.2 5.62C / raw 5.87C ACORN 2.2 warmed 0.43C / raw warmed 0.08C Average change per decade : ACORN 2.2 0.17C / raw 0.07C Grove 2000-2020 - ACORN 2.2 5.78C / raw 5.93C 1961-90 - ACORN 2.2 5.31C / raw 5.91C Pre 1972 .0 F rounding ACORN 2.2 - 18.93% / raw - 49.73% Post 1972 .0 C rounding ACORN 2.2 - 9.73% / raw - 12.95% The first decade, 1955-1964, averaged 4.93C in ACORN 2.2 and 5.52C in raw The final decade, 2011-2020, averaged 5.96C in ACORN 2.2 and 5.97C in raw 94069 overlap with 94220 17 June 2004 to 10 February 2010 : 94069 6.03C / 94220 5.59C 1994-2003 raw max averaged 5.84C and post AWS 2005-2014 averaged 5.76C Hobart
1918-1968 - ACORN 2.2 16.90C / raw 16.69C 1969-2020 - ACORN 2.2 17.62C / raw 17.41C ACORN 2.2 warmed 0.72C / raw warmed 0.72C Average change per decade : ACORN 2.2 0.12C / raw 0.14C Hobart 2000-2020 - ACORN 2.2 18.00C / raw 17.81C 1961-90 - ACORN 2.2 17.27C / raw 17.06C Pre 1972 .0 F rounding ACORN 2.2 - 18.89% / raw - 27.46% Post 1972 .0 C rounding ACORN 2.2 - 10.12% / raw - 11.69% The first decade, 1918-1927, averaged 17.03C in ACORN 2.2 and 16.81C in raw The final decade, 2011-2020, averaged 18.10C in ACORN 2.2 and 18.10C in raw Hobart has annual max temps back to 1883: 1883-1891 + 1894 + 1896-1907 16.79C ACORN catalogue: The site has been on the same property since its establishment in 1882. A new building was built in the area in 1966 and the screen was moved approximately 5 m to be clear of this. An automatic weather station was installed on 29 June 1992, and became the primary instrument on 1 November 1996. 1986-1995 raw max averaged 17.25C and post AWS 1997-2006 averaged 17.33C
1918-1968 - ACORN 2.2 8.58C / raw 8.13C 1969-2020 - ACORN 2.2 8.92C / raw 8.89C ACORN 2.2 warmed 0.34C / raw warmed 0.76C Average change per decade : ACORN 2.2 0.05C / raw 0.10C Hobart 2000-2020 - ACORN 2.2 9.11C / raw 9.10C 1961-90 - ACORN 2.2 8.76C / raw 8.65C Pre 1972 .0 F rounding ACORN 2.2 - 16.78% / raw - 31.79% Post 1972 .0 C rounding ACORN 2.2 - 9.81% / raw - 12.35% The first decade, 1918-1927, averaged 8.80C in ACORN 2.2 and 8.31C in raw The final decade, 2011-2020, averaged 9.25C in ACORN 2.2 and 9.25C in raw Hobart has annual min temps back to 1883: 1883-1891 + 1894 + 1896-1907 7.80C 1986-1995 raw min averaged 8.72C and post AWS 1997-2006 averaged 8.90C Launceston
1910-1965 - ACORN 2.2 17.01C / raw 17.86C 1966-2020 - ACORN 2.2 17.56C / raw 17.33C ACORN 2.2 warmed 0.55C / raw cooled 0.53C Average change per decade : ACORN 2.2 0.10C / raw -0.02C Launceston 2000-2020 - ACORN 2.2 17.88C / raw 17.82C 1961-90 - ACORN 2.2 17.31C / raw 16.99C Pre 1972 .0 F rounding ACORN 2.2 - 17.64% / raw - 34.68% Post 1972 .0 C rounding ACORN 2.2 - 9.97% / raw - 11.96% The first decade, 1910-1919, averaged 17.00C in ACORN 2.2 and 18.43C in raw The final decade, 2011-2020, averaged 17.98C in ACORN 2.2 and 18.12C in raw Launceston 91049 has annual max temps back to 1901: 1901-1902 + 1904-1909 17.78C 91049 overlap with 91104 1 April 1939 to 30 December 1959 : 91049 18.18C / 91104 16.61C 91104 overlaps with 91311 29 July 2004 to 16 June 2009 : 91104 17.59C / 91311 18.27C ACORN catalogue: The original site (091049) was at several locations around the centre of Launceston. There was a site move in December 1929 and further site moves on 29 March 1941, 29 September 1942 and 26 February 1948. Temperature observations continued at this location until 1959 but they were not used in ACORN-SAT after 1947. The first airport site (091104) was close to the terminal building and operated from 1939. It moved at some point in 1968–1969 to a location on the western side of the runway and north of the terminal. An automatic weather station was installed at this location on 19 May 1992 and became the primary instrument on 1 November 1996. The site continued until June 2009. The current site (091311) began operating at its current location 1.4 km southeast of the previous site on 12 July 2004. The airport is 160 m higher in elevation than the town, and is also further from the ocean. This results in markedly lower temperatures than those in the town, especially overnight. 1986-1995 raw max averaged 17.05C and post AWS 1997-2006 averaged 17.43C Launceston max Excel spreadsheets
1910-1965 - ACORN 2.2 5.14C / raw 6.98C 1966-2020 - ACORN 2.2 6.02C / raw 6.26C ACORN 2.2 warmed 0.88C / raw cooled 0.74C Average change per decade : ACORN 2.2 0.11C / raw -0.13C Launceston 2000-2020 - ACORN 2.2 6.29C / raw 6.29C 1961-90 - ACORN 2.2 5.73C / raw 6.32C Pre 1972 .0 F rounding ACORN 2.2 - 18.29% / raw - 40.79% Post 1972 .0 C rounding ACORN 2.2 - 10.19% / raw - 12.88% The first decade, 1910-1919, averaged 5.23C in ACORN 2.2 and 7.56C in raw The final decade, 2011-2020, averaged 6.29C in ACORN 2.2 and 6.29C in raw Launceston 91049 has annual min temps back to 1898: 1898 + 1902 + 1906-1909 6.20C 91049 overlap with 91104 1 April 1939 to 31 December 1959 : 91049 6.68C / 91104 5.95C 91104 overlaps with 91311 30 July 2004 to 17 June 2009 : 91104 6.39C / 91311 6.28C 1986-1995 raw min averaged 6.34C and post AWS 1997-2006 averaged 6.09C Launceston min Excel spreadsheets Low Head
1910-1965 - ACORN 2.2 15.80C / raw 15.74C 1966-2020 - ACORN 2.2 16.38C / raw 16.87C ACORN 2.2 warmed 0.58C / raw warmed 1.13C Average change per decade : ACORN 2.2 0.09C / raw 0.10C Low Head 2000-2020 - ACORN 2.2 16.66C / raw 16.66C 1961-90 - ACORN 2.2 16.18C / raw 16.90C Pre 1972 .0 F rounding ACORN 2.2 - 19.67% / raw - 65.03% Post 1972 .0 C rounding ACORN 2.2 - 10.17% / raw - 24.54% The first decade, 1910-1919, averaged 15.94C in ACORN 2.2 and 15.82C in raw The final decade, 2011-2020, averaged 16.75C in ACORN 2.2 and 16.75C in raw Low Head 91057 has annual max temps back to 1895: 1895-1899 + 1901-1909 = 15.61C 91057 overlap with 91293 8 January 1998 to 5 December 2001 : 91057 17.58C / 91293 16.65C ACORN catalogue: The original site (091057) was in the grounds of the Low Head lighthouse, which is on a small hill south of the headland. Prior to June 1937 the screen did not strictly meet Stevenson screen specifications, and was painted brown for a time around 1933, a period when the standard of observations was poor for a few years. Comparison of documentation from 1933 and 1940 indicate either a site move or new buildings during that time, with the latter being more likely. The site moved by 8 m in April 1949. At some point between 1968 and 1986 a gravel driveway was built in close proximity to the screen (the data suggest this occurred in about 1970). The site moved by 25 m on 15 August 1988. The automatic weather station (091293) began operating on 8 January 1998 at a site 200 m north of the previous location. Assuming the AWS was operational from 1998, 1988-1997 raw max averaged 17.12C and post AWS 1999-2008 averaged 16.59C Low Head max Excel spreadsheets
1910-1965 - ACORN 2.2 9.90C / raw 9.49C 1966-2020 - ACORN 2.2 10.29C / raw 10.07C ACORN 2.2 warmed 0.39C / raw warmed 0.58C Average change per decade : ACORN 2.2 0.07C / raw 0.11C Low Head 2000-2020 - ACORN 2.2 10.59C / raw 10.59C 1961-90 - ACORN 2.2 10.11C / raw 9.71C Pre 1972 .0 F rounding ACORN 2.2 - 15.95% / raw - 63.08% Post 1972 .0 C rounding ACORN 2.2 - 10.10% / raw - 28.10% The first decade, 1910-1919, averaged 10.02C in ACORN 2.2 and 9.62C in raw The final decade, 2011-2020, averaged 10.68C in ACORN 2.2 and 10.68C in raw Low Head 91057 has annual min temps back to 1895: 1895-1899 + 1901-1909 = 8.58C 91057 overlap with 91293 9 January 1998 to 12 December 2001 : 91057 10.07C / 91293 10.61C Assuming the AWS was operational from 1998, 1988-1997 raw min averaged 9.85C and post AWS 1999-2008 averaged 10.46C Low Head min Excel spreadsheets
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