Auditing the adjusting of ACORN temperature down under

Joanne Nova and Ken Stewart have uncovered some startling findings about the way Australia’s BOM “High Quality” network data is adjusted. Think USHCN here in America. This is well worth a read. – Anthony

A team of independent auditors, bloggers and scientists went through the the BOM “High Quality” (HQ) dataset and found significant errors, omissions and inexplicable adjustments. The team and Senator Cory Bernardi put in a Parliamentary request to get our Australian National Audit Office to reassess the BOM records. In response, the BOM, clearly afraid of getting audited, and still not providing all the data, code and explanations that were needed, decided to toss out the old so called High Quality (HQ) record, and start again. The old HQ increased the trends by 40% nationally, and 70% in the cities.

So goodbye “HQ”, hello “ACORN”. End result? Much the same.

That meant the ANAO could avoid an audit, since the BOM had changed data-sets, the point of auditing the old set was moot.

For me, this version is so much worse than the previous one. In the HQ data set the errors could have been inadvertent, but now we’ve pointed out the flaws, there can be no excuses for getting it wrong. Instead of fixing the flaws (and thanking the volunteers), it’s almost as if they’ve gone out of their way to not solve them. Instead it’s been complexified, rushed, has many typo’s and gaps, and the point (see below) about the “adjustments having no impact” — when they obviously do — begs to be audited by the Auditor General, the ACCC, Four Corners (ha ha) and 60 Minutes.

To make it all look o-so-convincing, the BOM asked three experts (from NOAA, NZ, and Canada) to look over it all, and score the BOM against its peers. But the peers standards are not too high in the first place: NOAA was caught with 89% of it’s own thermometers in the wrong spots near air conditioners and whatnot, and NZ’s records were so bad, they disowned them themselves. (NZ adjustimongered their temperature trends from 0.06C right up to 0.9C, got caught, and their response under legal pressure was to say but it’s ok, “There is no “official” or formal New Zealand Temperature Record”.)

How useful is it when a team of substandard institutions is asked  to evaluate whether the BOM practices are “amongst international best practice” when it is international best practice to ignore concrete, car-parks, tarmac, and lose the data too? We aren’t impressed if the BOM is as bad as the rest of the world, we want open data, transparent methods, and reproducible results. We want high quality to mean, well, high… quality.

So how good is the new ACORN (Australian Climate Observations Reference Network — Surface Air Temperature) set?

Because it covers a vast area, Alice Springs contributes 7-10% of the national signal.

ACORN and the BOM claim that since the new results are pretty much the same, really they give more confidence than ever that Australia has warmed since 1960.

Ken Stewart and the independent BOM analysts team have sliced and diced through the ACORN data.

They conclude:

1. Like the old HQ series, the Acorn record is also still impossible to replicate.
2. The record is much shorter than 100 years for many sites. It’s supposed to be high quality, but it has many gaps and spurious errors. If volunteers can write code on laptops to check for errors — and find, for example, that one 36.8C was accidentally changed to a 26.8C (and there are many) why can’t the Australian BOM?
3. Like the old series, Acorn’s trends are very different from what the raw data shows. (Why do we bother with thermometers?)
4. Hot and cold extremes have been adjusted, for the most part warming winters and cooling summers, and at some sites new and more extreme records have been set.

Too tricky by half? The BOM tries to hide the effect of adjustments

Here’s a piece of sleight of hand — ACORN, they claim, has a random set of a adjustments of both up and down (which is what we’d expect).

read more here