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Finally BoM releases some “secret” comparison data — a snow job revealing new thermometers are not comparable

Forced, dragged to comply, the BoM finally releases a little bit of side-by-side data so skeptics can start to compare old and new thermometers

Congratulations to Jennifer Marohasy. Her preliminary study on this new data is enough to show that the electronic thermometers are not equivalent to the older liquid-in-glass ones and temperatures measured in the same spot differ by as much as 0.3C. She’s now writing to Minister Josh Frydenberg that the consequences and questions raised by this are so serious that the BoM should not be announcing any new records. We need an audit!

It’s only temperature data — ?

Skeptics have been asking for comparison data between different types of thermometers for years to figure out just how much difference they make. The BoM mostly withholds that data, sometimes deletes it, and as a last resort follows the David Jones’ recommended method of dealing with unwanted questions — “snow the skeptics” (see Climategate). After all the blog posts, newspaper articles, and requests from the Minister, finally the BoM have helpfully sent the data for Mildura in the handy form of 4,000 scanned handwritten A8 forms.

Just like this one — how much fun can you have?

Bureau of Metorology, data record, Sept 1996, Mildura.

Bureau of Meteorology, data record, Sept 1996, Mildura.

This is what world-class modern data looks like.

Apparently, with only a million-dollars-a-day, the BoM can’t afford to digitize their thermometer data. The big question for me, is if this is the best data they have – how could they have analyzed it themselves to properly calibrate the thermometers — with hand-drawn graphs on paper? That would have been state of the art… in 1896. But this data was from 1989 to 2000, which includes the key years after November 1996, when the  electronic sensors started (and when most offices had computers). Perhaps by the twentieth anniversary of the change to new thermometers they will do an indepth calibration?  No wait… too late. Nevermind.

If the BoM did graph and calibrate those thermometers in a database, why couldn’t they just email that? We are not talking about market-sensitive corporate information. (Heck, it’s not like billions of dollars4,000 megawatts of wind power, and 25 million solar panels depends on data like this!) ;-).

Unfortunately for the BoM, Marohasy (and the other skeptics who helped with this processing, particularly Ken, Lance and Phill) want all the handwritten records and is prepared to transcribe the parts that matter by hand. In a matter of weeks she has already analyzed and published some preliminary information about the different thermometers at Mildura. Read it all at her blog site:

A Law Unto Themselves: The Australian Bureau of Meteorology

To paraphrase, she finds that:

“The bottom line is that since the introduction of automatic weather stations over 20 years ago, there has been no documented standard against which Australian temperatures at Mildura, or anywhere else, have been recorded. Of most concern to me is the muddling, (including by your staffers), of the numerical averaging-period with the time constant. The Bureau somewhat confusingly often refers to the time constant as the sensor “averages”.”

In this instance Marohasy looked at September (because the Bureau claimed there was a record hot day there this year). She found that the temperature differences are about 0.3C lower in the electronic sensors (which was not necessarily what we expected, though may be different in summer, or different in other stations).  If the Mildura sensor was somehow reading low, it might make the latest record an underestimate (don’t the BoM care?) but, but, but, the sensor has changed again since the late 1990s, the Stevenson Screen was replaced with a smaller version, and the BoM have gone from one-minute averaging to one-second records.  How many ways can we mess up the climate signal? It looks like the BoM were averaging over one minute back in 1997 – 1999, but the recent “record” was the one-second-record type. If true, this, obviously, changes everything.

Bureau of Meoteorology, Data records, Mildura, 1996.

Finally, side-by-side, Max temperatures in Mildura, 1996. (One example of the key section cut from the image above)

The BoM needs auditing

These temperature recordings are now the primary input data which determine a range of scientific predictions, projections and model outputs with enormous, fiscal, economic and political implications both for Australia and internationally. If these temperature recordings are wrong then all the consequent scientific, fiscal, economic and political decisions based on this data may be wrong also.

The fiscal records of government agencies are independently and regularly audited for amounts far less than the fiscal and economic impacts of global warming policies so it would seem only prudent and reasonable that the temperature records of the Bureau of Meteorology, which have such huge fiscal and economic impacts, should be subject to a similar audit regime to ensure their accuracy, integrity and reliability.

Every “record” temperature the BoM issues from an electronic station is suspect because of the assumption the BoM makes that the electronic sensors are “equivalent” to the old style mercury and alcohol ones. (And the other stations are suspect because they’ve been homogenized, but that’s another story).

 When o’ when did the one-second-records start? Only the BoM knows.


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