ACORN-SAT version 2.3

ACORN-SAT version 2.3 was release 2022-11-18. Version 2.3 has temperatures records from 1910 up until the end of 2021, for the 112 locations around Australia included in ACORN-SAT.

The map below (from ClimateExplorer) shows heating scores calculated from version 2.3 of ACORN-SAT. Canberra is no longer the only location that has a heating score of 9. There are now 5 sites that share that score.

Heating score is a relative metric; it’s the result of comparing all warming indexes with all others in the dataset. The other sites (Alice Springs, Cunderdin, Marree, Snowtown) were boosted to a 9 because they had warmer than average temperatures in 2021. Canberra had its first cooler than average temperature since 1996 (25 years). That reduced Canberra’s warming index from 1.8°C to 1.7°C.

The Bureau of Meteorology released a statement about version 2.3 on their ACORN-SAT website, reproduced below.

New and reassessed adjustments as part of ACORN-SAT version 2.3

ACORN-SAT 2.3 includes new or reassessed adjustments at 16 of the 112 ACORN-SAT locations. Previously applied adjustments at 7 locations were removed after being found to be no longer significant with the inclusion of additional data.

Analysis has shown the changed adjustments in ACORN-SAT 2.3 have had a negligible impact on estimated long-term warming trend in Australia.

Full details of all adjustments, including the time periods and reference periods used, are available in the station catalogue. The Bureau’s ACORN-SAT dataset and methods have been thoroughly peer-reviewed and found to be world-leading. Further information on the dataset and the reasons for adjustments can be found in the ACORN-SAT FAQ section.