Bureau of Meteorology told to be more transparent

THE Bureau of Meteorology was told to be more transparent and make public all details of the computer models used to adjust temperature records.

THE Bureau of Meteorology was told to be more transparent and make public all details of the computer models used to adjust historic temperature records by the peer review panel that cleared its work as world best practice.

The 2011 independent panel told BOM to clearly explain any changes that were made between raw and “homogenised” data.

BOM yesterday rejected claims it was altering climate records to exaggerate estimates of global warming, but it has not disputed that temperature trends at some sites had changed from slight cooling to warming after homogenisation.

Critics have said BOM’s exact methodology and reasons for any changes had not been properly explained publicly.

“Homogenisation is carried out by meteorological authorities around the world as best practice, to ensure that climate data is consistent through time,’’ BOM said.

It said both raw and adjusted national temperature data and the larger unadjusted national data set all indicate that Australian air temperatures had warmed over the past century.

“These findings are also consistent with those of other leading international meteorological authorities, such as NOAA and NASA in the US and the UK Met­Office,’’ BOM said.

The bureau has been under fire for not making publicly available the methodology used for homogenisation. Michael Asten from the School of Earth Atmosphere and Environment at Monash University said confidence in BOM’s data would increase “if and when BOM publishes or supplies its homogenisation algorithms, a step which would be quite consistent with existing ­requirements of the better peer-reviewed journals.’’

BOM said its methods had been published in peer-reviewed scientific journals but did not say where or in what form.

Independent scientist Jennifer Marohasy, who has questioned the change in temperature trend towards greater warming at a number of sites she has studied said BOM’s response had been riddled with “half truths and ­untruths’’.

“The bureau claims it makes a raw data comparison but it does not,” Dr Marohasy said. “At least there is no report or published paper that shows the raw un­homogenised and untruncated values,’’ she said.

Dr Marohasy said it was not disputed that NOAA, NASA and the UK Met Office get the same result as BOM because they used the same homogenisation techniques.

BOM’s 2011 independent panel said it was “satisfied overall” with the bureau’s methodology but it “encouraged” the bureau to improve the public transparency of the process used.

The panel recommended a list of adjustments be made publicly available along with the adjusted temperature series including the rationale for each adjustment. It said the computer codes underpinning the national ACORNSAT data-set, including the algorithms and protocols used by BOM for data quality control, should be made publicly available.