Two Decades of Temperature Data from Australia – Not Fit for Purpose

By Paul Homewood

An important post from Jennifer Marohasy:

Australia is a large continent in the Southern Hemisphere. The temperatures measured and recorded by the Australian Bureau of Meteorology contribute to the calculation of global averages. These values, of course, suggest catastrophic human-caused global warming.

Two decades ago the Bureau replaced most of the manually-read mercury thermometers in its weather stations with electronic devises that could be read automatically – so since at least 1997 most of the temperature data has been collected by automatic weather stations (AWS).

Before this happened there was extensive testing of the devises – parallel studies at multiple site to ensure that measurements from the new weather stations tallied with measurements from the old liquid-in-glass thermometers.

There was even a report issued by the World Meteorological Organisation (WMO) entitled ‘Instruments and Observing Methods’ (Report No. 65) that explained because the modern electronic probes being installed across Australia reacted more quickly to second by second temperature changes, measurements from these devices need to be averaged over a one to ten-minute period to provide some measure of comparability with the original thermometers. The same report also stated that the general-purpose operating range of the new Australian electronic weather stations was minus 60 to plus 60 degrees Celsius.

This all seems very sensible, well-documented, and presumably is now Bureau policy.

Except, this winter I have discovered none of this policy is actually being implemented.

Rather than averaging temperatures over one or ten minutes, the Bureau is entering one second extrema. This would bias the minima downwards, and the maxima upwards. Except that the Bureau is placing limits on how cold an individual weather station can record a temperature, so most of the bias is going to be upwards.

Jen Marohasy at the Goulburn weather station where the Bureau acknowledges it set a limit of minus 10 degrees on how cold a temperature could be recorded this winter, never mind that this AWS recorded minus 10.9 degrees Celsius during a previous winter.

I have known for some time that the Bureau remodel these recordings in the creation of the homogenised Australian Climate Observations Reference Network – Surface Air Temperatures (ACORN-SAT), which is subsequently incorporated into HadCRUT, which is used to inform the United Nation’s Intergovernmental Panel on Climate Change (IPCC). Nevertheless, I naively thought that the ‘raw data’ was mostly good data. But now I am even sceptical of this.

As someone who values data above most else – this is a stomach-churning revelation.

Indeed, it could be that the last 20-years of temperature recordings by the Bureau will be found not fit for purpose, and will eventually need to be discarded. This would make for a rather large hole in the calculation of global warming – given the size of Australia.

Read the full post here.