Jennifer Marohasy, Lance Pidgeon, Bureau of Meteorology, Australia, cold temperatures, scandal, adjustments, climate change, global warming.

Jennifer Marohasy, Lance Pidgeon, at the Stevenson screen, Goulburn Airport.


Isn’t it amazing, the power of the media.

Suddenly, the Bureau of Meteorology needs to replace equipment and answer questions and set up an internal inquiry.

But they’ve had weeks of warning.

Lance Pidgeon and Jennifer Marohasy have been watching the automatic weather stations record very cold temperatures, and then astonished when those same readings either got entered into our national raw database as warmer, or simply disappeared.

The BOM apparently has a filter set so that super cold temperatures need to be manually checked. Yet the filter is set so high, in Thredbo’s case, nearly five whole degrees warmer than temperatures already recorded.

Wow. Just wow. What does raw data mean anymore?

The lack of respect for real observations is profoundly unscientific. How much does the BOM even care about understanding our climate if they are so flagrantly uninterested in the data?  As I have said, the Bureau of Meteorology behaves more like PR agency than an institute of science. Based on past practice their internal inquiry will find excuses, not answer the questions, and will not fix appalling methodology.  The BOM needs a full external audit (what are they so afraid of?).

The BOM admits temperature adjustments are secret and thus completely unscientific. If we had a team to audit the dataset, as we requested in 2011, or to replicate the data as I requested in Sept 2014, this erasure of cold temperatures would have been fixed by now.

How much data has been lost forever?

The Bureau of Meteorology Budget was 365.3 million in 2015-16. The Australian climate is a national crisis, but the Bureau won’t publish it’s methods in full, aren’t doing basic quality control checks, and can’t employ even one person to answer questions about its secret methods?

On July 5th I asked many questions, and now nearly a month later, we still have no answers:

… this opens a whole can of worms in so many ways — what are these “limits”, do they apply equally to the high side records, who set them, how long has this being going on, and where are they published? Are the limits on the high temperatures set this close to previously recorded temperatures? How many times have raw records been automatically truncated?

Jennifer Marohasy points out that these stations are used to homogenize other stations which are supposed the best stations used in the ACORN dataset. So when the BOM protest that they are not manipulating the data, it’s obvious that they are.

Graham Lloyd, The Australian

The Bureau of Meteorology has ordered a full review of temperature recording equipment and procedures after the peak weather agency was caught tampering with cold winter temperature logs in at least two locations.

Bush meteorologist Lance Pidgeon blew the whistle on the missing data after watching the minus 10.4C Goulburn recording from July 2 disappear from the bureau’s website. “The temperature dropped to minus 10.4, stayed there for some time and then it changed to minus 10 and then it disappeared,” Mr Pidgeon said.

He relayed his concerns to scientist Jennifer Marohasy, who has queried the bureau’s treatment of historical temperature data. After questions were asked, the bureau restored the original recording of minus 10.4C to its website. A bureau spokeswoman said the low recording had been checked for “quality assurance” before being posted.

The bureau said limits were set on how low temperatures could go at some stations before a manual check was needed to confirm them. “The bureau’s quality ­control system, designed to filter out spurious low or high values was set at minus 10 minimum for Goulburn which is why the record automatically adjusted,” a bureau spokeswoman said.

A similar failure had deleted a reading of minus 10.4 at Thredbo Top on July 16 even though temperatures at that station had been recorded as low as minus 14.7 in the past. That temperature was still blank on the bureau’s website yesterday.

The bureau did not respond to questions about how widely the quality control system had been applied and at what upper temperature the cut-off had been set.

Dr Marohasy has evidence of the initial minus 10.4C recording at Thredbo before it was deleted for quality ­assurance.

“This either reflects an extraordinary incompetence, or a determination to prevent evidence of low temperatures,” Dr Marohasy said.

Would the BOM be doing anything if The Australian was not being so dedicated and critical?

Where is the ABC or Fairfax? Do they care about the climate?

The Australian has an editorial position on this also:  Bureau clouds weather debate

That adjustment process, known as homogenisation, has got the bureau in trouble in the past.

Again, the issue has been one of transparency. The bureau has made a series of changes to historical records across the country. It says it does so to adjust for the movement of a weather station site, changes to surrounding vegetation or results that look wrong when compared with nearby sites. Such homogenisation is not unique to Australia but the bureau sometimes fails to convince when asked to explain the specific local adjustments it has made, especially if these bolster a warming trend. The same goes for any practices that discount cold temperatures.

The official record must be accurate and trusted. Otherwise, claims of historic extremes — the hottest winter day! — only mislead and public policy gets corrupted. Even if the bureau does have all the answers, it needs to do a better job of taking the public — sceptics included — into its confidence.

Background Information:

Jennifer Marohasy has been laying out the evidence on her blog:

Bureau Erases Goulburn Record Minimum Temperature: Set Sunday 2 July 2017

Bureau Now Sets Strict Limits on Cooling

Bureau Still Limiting Cooling to Minus 10 Degrees

Bureau Misleads Minister Frydenberg on Goulburn

On Sunday, Goulburn got colder than the BOM thought was possible (and a raw data record was “adjusted”).

The Australian:

BoM opens cold case on temperature data