The documents, released after a years-long Freedom of Information campaign, show temperature measurements taken using updated BOM probes in automatic weather stations at the Brisbane Airport site could be up to 0.7C warmer than the temperature taken using a traditional thermometer at the same time at the same site.

More than three years after a FOI request for parallel data was lodged by scientist John Abbot, the BOM released three years of data on Easter eve after the matter was taken to the Administrative Appeals Tribunal.

In the end, the BOM released only limited data, paving the way for a wave of FOI demands that full records be released in the public interest.

Release of the data is the first opportunity to analyse the performance of BOM probes alongside mercury thermometers. The bureau has long claimed the readings are identical but critics have said the BOM was not following World Met­eor­­ological Organisation guidelines on how they should be used.

Given that even small variations in temperature recordings can have an impact on the long-term record, accuracy is vital.
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“The public is constantly being told of impending global catastrophe should temperatures rise by more than 1.5C. Discrepancies of more than 0.5C because of instrumentation differences are therefore very significant, and certainly should satisfy the public interest test”, Dr Abbot said.

The Oz