ACORN 2.2 influence on Northern Territory temperature trendsAustralia New South Wales Queensland South Australia Tasmania Victoria Western Australia
There are five ACORN stations (Australian Climate Observation Reference Network) in the Northern Territory. This page analyses the daily temperatures at all five weather stations and averages the three with a start year of 1910 to ensure a uniform timescale. The other two excluded stations have temperature recordings starting in years after 1910, the most recent being Rabbit Flat with a start year of 1970. The three long-term weather stations analysed on this page (with a start year of 1910) had a 1910-1964 average maximum of 30.05C in ACORN 2.1 and a 1910-1964 average maximum of 30.18C in ACORN 2.2 - a 0.13C warming of historic maxima. The three long-term weather stations had a 1910-1964 average minimum of 18.03C in ACORN 2.1 and a 1910-1964 average minimum of 18.32C in ACORN 2.2 - a 0.29C warming of historic minima. However, more recent decades have been warmed more than historic decades, resulting in a slight increase in Northern Territory temperatures since 1910 with the advent of ACORN 2.2. 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 Northern Territory stations begin in 1910 and end in 2020 in ACORN 2.2 and RAW - Alice Springs, Darwin and Tennant Creek. The first charts below show average 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 five sites since 1910.
1910-1964 - ACORN 2.2 30.18C / raw 30.83C 1965-2020 - ACORN 2.2 31.20C / raw 31.11C ACORN 2.2 warmed 1.02C / raw warmed 0.28C Average change per decade : ACORN 2.2 0.20C / raw 0.08C Northern Territory 2000-2020 - ACORN 2.2 31.55C / raw 31.45C The first decade, 1910-1919, averaged 29.74C in ACORN 2.2 and 30.84C in raw The final decade, 2011-2020, averaged 31.85C in ACORN 2.2 and 31.78C in raw 1961-90 - ACORN 2.2 - 30.83C / raw 30.82C Download Excel spreadsheet for three NT weather stations in ACORN 1, ACORN 2.2 and RAW
1910-1964 - ACORN 2.2 18.32C / raw 18.43C 1965-2020 - ACORN 2.2 18.82C / raw 18.77C ACORN 2.2 warmed 0.50C / raw warmed 0.34C Average change per decade : ACORN 2.2 0.08C / raw 0.03C Northern Territory 2000-2020 - ACORN 2.2 19.01C / raw 18.82C The first decade, 1910-1919, averaged 18.20C in ACORN 2.2 and 18.45C in raw The final decade, 2011-2020, averaged 19.09C in ACORN 2.2 and 18.89C in raw 1961-90 - ACORN 2.2 - 18.53C / raw 18.61C Download Excel spreadsheet for three NT weather stations in ACORN 1 and ACORN 2.2 and RAW Station menu Alice Springs, Darwin, Rabbit Flat, Tennant Creek, Victoria River Downs Alice Springs
1910-1965 - ACORN 2.2 28.14C / raw 28.31C 1966-2020 - ACORN 2.2 29.32C / raw 29.09C ACORN 2.2 warmed 1.18C / raw warmed 0.78C Average change per decade : ACORN 2.2 0.22C / raw 0.11C Alice Springs 2000-2020 - ACORN 2.2 29.63C / raw 29.63C 1961-90 - ACORN 2.2 28.98C / raw 28.59C Pre 1972 .0 F rounding ACORN 2.2 - 16.98% / raw - 50.52% Post 1972 .0 C rounding ACORN 2.2 - 10.10% / raw - 11.34% The first decade, 1910-1919, averaged 27.45C in ACORN 2.2 and 28.52C in raw The final decade, 2011-2020, averaged 30.00C in ACORN 2.2 and 30.00C in raw Alice Springs 15540 has annual max temps back to 1879: 1879-1889 + 1891 +1893-1909 = 28.85C 15540 overlap with 15590 1 November 1941 to 31 December 1953 : 15540 28.51C / 15590 28.13C ACORN catalogue: The original site (015540) was at the Telegraph Station, 3 km north of the town. There is no known documentation of the screen type at the Telegraph Station but the observations are consistent with a Stevenson screen having been used there. The site was enclosed by a rock wall about 1 m high and painted white that would have interrupted wind flow and reflected heat. Observations moved to the Post Office on 23 January 1932. The Post Office site continued until 1953 but data after 1944 were not used in ACORN-SAT as there appear to have been changes at the Post Office site around the time that the airport site opened. Measurements have been taken at the airport (015590) since 1941. There was a site move (550 m east-northeast) in July 1974. An automatic weather station was installed on 21 March 1991 and became the primary instrument on 1 November 1996. The site moved a few metres west on 27 May 2002. 1986-1995 raw max averaged 28.95C and post AWS 1997-2006 averaged 29.48C Alice Springs max Excel spreadsheets
1910-1965 - ACORN 2.2 11.90C / raw 13.13C 1966-2020 - ACORN 2.2 12.44C / raw 13.21C ACORN 2.2 warmed 0.54C / raw warmed 0.08C Average change per decade : ACORN 2.2 0.10C / raw -0.02C Alice Springs 2000-2020 - ACORN 2.2 13.00C / raw 13.26C 1961-90 - ACORN 2.2 11.86C / raw 13.10C Pre 1972 .0 F rounding ACORN 2.2 - 17.73% / raw - 55.40% Post 1972 .0 C rounding ACORN 2.2 - 9.77% / raw - 11.44% The first decade, 1910-1919, averaged 12.13C in ACORN 2.2 and 13.32C in raw The final decade, 2011-2020, averaged 13.26C in ACORN 2.2 and 13.26C in raw Alice Springs 15540 has annual min temps back to 1879: 1879-1902 + 1904-1909 = 12.83C 15540 overlap with 15590 1 November 1941 to 31 December 1953 : 15540 12.46C / 15590 12.86C 1986-1995 raw min averaged 13.68C and post AWS 1997-2006 averaged 13.24C Alice Springs min Excel spreadsheets Darwin
1910-1965 - ACORN 2.2 31.05C / raw 32.09C 1966-2020 - ACORN 2.2 32.16C / raw 32.25C ACORN 2.2 warmed 1.11C / raw warmed 0.16C Average change per decade : ACORN 2.2 0.18C / raw 0.03C Darwin 2000-2020 - ACORN 2.2 32.50C / raw 32.50C 1961-90 - ACORN 2.2 31.74C / raw 32.02C Pre 1972 .0 F rounding ACORN 2.2 - 18.07% / raw - 32.61% Post 1972 .0 C rounding ACORN 2.2 - 9.74% / raw - 11.31% The first decade, 1910-1919, averaged 30.83C in ACORN 2.2 and 32.38C in raw The final decade, 2011-2020, averaged 32.68C in ACORN 2.2 and 32.68C in raw Darwin 14016 has annual max temps back to 1885: 1885-1909 = 32.97C 14016 overlap with 14015 1 February 1941 to 31 January 1942 : 14016 31.42C / 14015 30.85C ACORN catalogue: Earlier observations were made at the Post Office (014016), in the central city area. This is on a peninsula in Darwin Harbour which means that the prevailing dry-season southeasterlies have a trajectory over Darwin Harbour (whereas at the airport they are over land). The site deteriorated progressively from the mid-1930s, becoming overshadowed by trees, especially after 1937. The site (along with the remainder of the Post Office) was destroyed in the Japanese air raids of February 1942 and never rebuilt. The airport site (014015) has been operating since February 1941. An automatic weather station was installed on 1 October 1990 and became the primary instrument on 1 November 1996. The site moved about 900 m east (along the southern edge of the airport) on 7 August 2001, with observations at the original site continuing under the station number 014040 until June 2007. 1986-1995 raw max averaged 32.11C and post AWS 1997-2006 averaged 32.24C
1910-1965 - ACORN 2.2 22.69C / raw 23.37C 1966-2020 - ACORN 2.2 23.21C / raw 23.31C ACORN 2.2 warmed 0.52C / raw cooled 0.06C Average change per decade : ACORN 2.2 0.07C / raw -0.03C Darwin 2000-2020 - ACORN 2.2 23.21C / raw 23.21C 1961-90 - ACORN 2.2 23.07C / raw 23.29C Pre 1972 .0 F rounding ACORN 2.2 - 16.47% / raw - 33.85% Post 1972 .0 C rounding ACORN 2.2 - 9.25% / raw - 11.88% The first decade, 1910-1919, averaged 22.59C in ACORN 2.2 and 23.62C in raw The final decade, 2011-2020, averaged 23.27C in ACORN 2.2 and 23.27C in raw Darwin 14016 has annual min temps back to 1885: 1885-1909 = 23.56C 14016 overlap with 14015 1 February 1941 to 31 January 1942 : 14016 24.20C / 14015 22.67C 1986-1995 raw min averaged 23.60C and post AWS 1997-2006 averaged 23.13C Rabbit Flat
1970-1994 - ACORN 2.2 33.79C / raw 33.46C 1995-2019 - ACORN 2.2 34.02C / raw 34.04C ACORN 2.2 warmed 0.23C / raw warmed 0.58C Average change per decade : ACORN 2.2 0.15C / raw 0.30C Rabbit Flat 2000-2020 - ACORN 2.2 34.00C / raw 34.00C Pre 1972 .0 F rounding ACORN 2.2 - 17.93% / raw - 22.42% Post 1972 .0 C rounding ACORN 2.2 - 10.38% / raw - 12.69% The first decade, 1970-1979, averaged 33.50C in ACORN 2.2 and 32.87C in raw The final decade, 2011-2020, averaged 34.29C in ACORN 2.2 and 34.29C in raw 15548 overlap with 15666 15 November 1996 to 30 November 1998 : 15548 34.42C / 15666 34.10C ACORN catalogue: The first site (015548) has no indication of any moves between 1969 and 1998 but did become rather overgrown over time. The automatic weather station was installed about 200 m to the west in 1996. The two sites operated in parallel from 1996 to 1998. There is no indication of any moves at the new site. Assuming the AWS was operational from 1996, 1986-1995 raw max averaged 34.13C and post AWS 1997-2006 averaged 33.71C Rabbit Flat max Excel spreadsheets
1970-1994 - ACORN 2.2 16.74C / raw 16.33C 1995-2019 - ACORN 2.2 16.73C / raw 16.64C ACORN 2.2 cooled 0.01C / raw warmed 0.31C Average change per decade : ACORN 2.2 0.17C / raw 0.09C Rabbit Flat 2000-2020 - ACORN 2.2 16.55C / raw 16.55C Pre 1972 .0 F rounding ACORN 2.2 - 19.03% / raw - 33.01% Post 1972 .0 C rounding ACORN 2.2 - 10.52% / raw - 14.82% The first decade, 1970-1979, averaged 15.94C in ACORN 2.2 and 16.25C in raw The final decade, 2011-2020, averaged 16.63C in ACORN 2.2 and 16.63C in raw 15548 overlap with 15666 15 November 1996 to 30 November 1998 : 15548 17.47C / 15666 17.89C Assuming the AWS was operational from 1996, 1986-1995 raw min averaged 16.37C and post AWS 1997-2006 averaged 16.72C Rabbit Flat min Excel spreadsheets Tennant Creek
1911-1965 - ACORN 2.2 31.42C / raw 32.18C 1966-2020 - ACORN 2.2 32.13C / raw 32.00C ACORN 2.2 warmed 0.71C / raw cooled 0.18C Average change per decade : ACORN 2.2 0.17C / raw 0.07C Tennant Creek 2000-2020 - ACORN 2.2 32.53C / raw 32.21C 1961-90 - ACORN 2.2 31.80C / raw 31.87C Pre 1972 .0 F rounding ACORN 2.2 - 18.38% / raw - 61.79% Post 1972 .0 C rounding ACORN 2.2 - 10.08% / raw - 11.78% The first decade, 1911-1920, averaged 30.98C in ACORN 2.2 and 31.67C in raw The final decade, 2011-2020, averaged 32.88C in ACORN 2.2 and 32.66C in raw 15087 overlap with 15135 27 July 1969 to 31 October 1970 : 15087 32.36C / 15135 32.04C ACORN catalogue: The original site (015087) was based in the town. There was a major move (12 km south) in June 1935 and a smaller move of about 20 m in November 1963. This later site was quite close to a road. New screens were installed to replace damaged ones in May 1945 and November 1958. Observations ceased in 1970. This airport site has been operating since 1969. An automatic weather station was installed on 8 July 1990 and has been the primary instrument since 1 November 1996. There are no known substantial moves at this location. 1986-1995 raw max averaged 32.27C and post AWS 1997-2006 averaged 31.81C Tennant Creek max Excel spreadsheets
1911-1965 - ACORN 2.2 20.34C / raw 18.75C 1966-2020 - ACORN 2.2 20.81C / raw 19.79C ACORN 2.2 warmed 0.47C / raw warmed 1.04C Average change per decade : ACORN 2.2 0.07C / raw 0.14C Tennant Creek 2000-2020 - ACORN 2.2 20.82C / raw 19.98C 1961-90 - ACORN 2.2 20.65C / raw 19.42C Pre 1972 .0 F rounding ACORN 2.2 - 18.16% / raw - 64.64% Post 1972 .0 C rounding ACORN 2.2 - 9.61% / raw - 11.81% The first decade, 1911-1920, averaged 19.99C in ACORN 2.2 and 18.56C in raw The final decade, 2011-2020, averaged 20.74C in ACORN 2.2 and 20.13C in raw 15087 overlap with 15135 25 July 1969 to 31 October 1970 : 15087 18.56C / 15135 18.91C 1986-1995 raw min averaged 20.43C and post AWS 1997-2006 averaged 19.90C Tennant Creek min Excel spreadsheets Victoria River Downs
1965-1991 - ACORN 2.2 35.17C / raw 34.61C 1992-2019 - ACORN 2.2 34.92C / raw 34.55C ACORN 2.2 cooled 0.25C / raw cooled 0.06C Average change per decade : ACORN 2.2 0.04C / raw 0.08C Victoria River Downs 2000-2020 - ACORN 2.2 34.93C / raw 34.68C Pre 1972 .0 F rounding ACORN 2.2 - 21.65% / raw - 40.40% Post 1972 .0 C rounding ACORN 2.2 - 10.85% / raw - 18.74% The first decade, 1965-1974, averaged 34.91C in ACORN 2.2 and 34.76C in raw The final decade, 2011-2020, averaged 35.24C in ACORN 2.2 and 35.24C in raw ACORN catalogue: The site moved 250 m northwest in August 1987. An automatic weather station was installed on 9 May 1997. Station photos indicate that the grass was watered up until around 2007; data indicate a marked increase in maximum temperatures around this time, especially during the dry season. 1987-1996 raw max averaged 34.62C and post AWS 1998-2007 averaged 34.07C Victoria River Downs max Excel spreadsheets
1965-1991 - ACORN 2.2 20.17C / raw 19.91C 1992-2019 - ACORN 2.2 19.53C / raw 19.41C ACORN 2.2 cooled 0.64C / raw cooled 0.50C Average change per decade : ACORN 2.2 0.03C / raw 0.01C Victoria River Downs 2000-2020 - ACORN 2.2 19.43C / raw 19.43C Pre 1972 .0 F rounding ACORN 2.2 - 18.80% / raw - 49.05% Post 1972 .0 C rounding ACORN 2.2 - 10.86% / raw - 17.82% The first decade, 1965-1974, averaged 19.46C in ACORN 2.2 and 19.55C in raw The final decade, 2011-2020, averaged 19.53C in ACORN 2.2 and 19.53C in raw 1987-1996 raw min averaged 19.94C and post AWS 1998-2007 averaged 19.43C Victoria River Downs min Excel spreadsheets
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