BOM homogenization errors are so big they can be seen from space

It’s just not cricket. And in so many ways.

Shame to let a perfectly good dataset go to waste… Australian data comes from some of the longest stations running in the Southern Hemisphere, it could be useful. Instead we get more evidence here that the BOM’s magical and secret homogenization adjustments can take poor data and spread false signals into better data. Homogenisation errors are already visible in a site-by-site analysis, but this shows the problems may be so big they affect averages across the whole of Australia, and we can detect them with satellites.

Tom Quirk continues comparing the satellite record of Australia with the BOM surface version. Previously, he (and for the record, Ken Stewart in 2015) showed that some discrepancies are due to the effect of heavy rain or drought. But now he looks further and finds that not-so-coincidentally, the largest gaps and most “inexplicable” differences occur in the mid nineteen-nineties, the same years the BoM shifted from using old large Stevenson screens to electronic thermometers. Around the same time, the large screens were often also swapped for much smaller ones too — like double jeopardy for data. Oddly, spookily, the BOM makes many adjustments to data […]