“Instrument errors, noise, may account for a quarter to one half of our national warming trend in the last century".

     When the newspapers run a headline with Sydney hits, say, 44.4 degrees and that number gets engraved in history, who realizes that the extreme heat may have only lasted one second? You might think the maximum temperatures were above 44 for at least ten minutes, but the BOM will write it into the record books even if that heat lasts one second, and if the temperature a minute before was more than a whole degree cooler.

     We’re writing puffs of jet emissions, car exhaust, or random packets of hot (or cold) air into history books, and comparing these new records with old ones done in slow reacting liquid in glass thermometers. No wonder we are setting records!

     In the last twenty years, electronic sensors have replaced most of the old fashioned thermometers. It’s for exactly this reason that we need the side-by-side comparison data that Bill Johnston asked for and which the BOM can’t supply because it is deleting the data  – as a matter of routine practice.

     Back in 1910, or even 1990, thermometers were not able to record a spike of heat (or cold) that lasted for such a short time. Liquid-in-glass thermometers just can’t react that fast (who remembers waiting with a thermometer under their tongue as a child?)

     This is not just about headline grabbing records, but about temperatures recorded every day and used to calculate long term trends. The effect of bringing in newer more sensitive thermometers in the mid nineties could cause a “step up” in maximum temperatures.
The BOM needs an audit. <http://joannenova.com.au/2017/08/bom-scandal-heats-up-kininmonth-watts-nova-quoted-in-the-australian-we-audit-banks-why-not-bom/>  
A full independent audit – is needed.

     Any politician who cares about the climate would order one immediately.
Meteorologists debate whether it should be 5 minute or 7 minute averaging, not 1 second….”
Continue reading here: One second records in Australia — how “noise” creates history and a warming trend