"For some time, weather enthusiasts have been noticing rapid temperature fluctuations at the ‘latest observations’ page at the Bureau’s website. For example, Peter Cornish, a retired hydrologist, wrote to the Bureau on 17 December 2012 asking whether the 1.5 degrees Celsius drop in temperature in the space of one minute at Sydney’s Observatory Hill, just the day before, could be a quirk of the new electronic temperature sensors. Ken Stewart, a retired school principal, requested temperature data for Hervey Bay after noticing a 2.1 degrees Celsius temperature change in the space of one minute on 22 February 2017.

In both cases, the Bureau assured these ‘amateurs’ that they didn’t understand what they were noticing. In the case of Dr Cornish, he was referred to a Bureau report that makes reference to international studies, which explains how measurements from the fast responding electronic sensors are made comparable with measurements from the more inert mercury thermometers by averaging over at least one minute – except the Bureau does not actually average any of the measurements recorded from its custom-built sensors.

Electronic sensors, progressively installed into Bureau weather stations replacing mercury thermometers, beginning some twenty years ago, can capture rapid changes in temperature. On a hot day, the air is warmed by turbulent streams of ground-heated air that can fluctuate by more than two degrees on a scale of seconds. So, if the Bureau simply changed from mercury thermometers to electronic sensors, it could increase the daily range of temperatures, and potentially even generate record hot days approach 50 degrees Celsius, because of the faster response time of the sensors.

Except to ensure consistency with measurements from mercury thermometers there is an international literature, and international standards, that specify how spot-readings need to be averaged – a literature and methodology being ignored by the Bureau. For example, the UK Met office takes 60 x 1-second samples each minute from its sensors and then averages these. In the US, they have decided this is too short a period, and the standard there is to average over a fixed five-minute period.

The Weather Observers Handbook 2012, for example, states that if averaging is not over a five-minute period it affects temperature extremes. An example is even provided. Dodge City, Kansas, has a long temperature record dating back to 1875. The hottest day on record stood at 43.3 degree Celsius. Then there was a heatwave in 2011, the highest reading from an electronic sensor was 43.9 degree Celsius. But when it was found this record was from readings that had only been averaged over only one minute, the new record was scratched – because when the same readings were averaged over the ASOS standard of five minutes, the maximum temperature was 43.3 degree Celsius – a tie.

In Australia, our Bureau takes not five-minute averages, nor even one-minute averages. As Ken Stewart discovered when he persisted with understanding the nature of the data he had been provided by the Bureau from Hervey Bay: the Bureau just take one-second spot-readings."

"The letter explains that all the sensors the Bureau uses have been ‘purpose-designed’. I had been requesting manufacture’s specifications, but instead, I received this advice that it’s to Bureau specifications and, by inference, there is no documentation. To be clear, there are also no reports detailing the laboratory and field tests that explain how the custom-built devices have been designed to ‘closely mirrors’ the behaviour of mercury thermometers including the time constants – to quote from Dr Johnson’s letter of last Friday."

https://www.spectator.com.au/2017/10/more-hot-days-or-temperature-sensors-at-pla...

Rider wrote on Oct 28^th, 2017 at 7:28pm:

Do you even know which side your bread is buttered on?

Over the years.
Hasn't BOM been the most consistently most clicked on site by Australians?

I agree with Lee
f ark the BOM, when I want to know what's happening in the world of climate I'll ask Lord Monkton 

Bobby. wrote on Nov 11^th, 2017 at 9:04pm:



What the bugger has monk to do with anything? you're an idiot bobby

Bobby. wrote on Nov 11^th, 2017 at 9:04pm:

Why don't you tell us about them?

Jasin wrote on Nov 11^th, 2017 at 6:59pm:



I wonder why?  Which scenario fits best do you reckon for the 99% of normal Aussies?

Scenario 1.
I wonder what the weather will be like for camping this weekend?

Scenario 2.
I wonder how my great, great grandkids will be able to handle an increase/decrease in a virtually unmeasureable statistically meaningless 0.05 celcius temperature change in 150 years time?

Monk didn't understand the idea of an under-damped closed loop control system
which appears to be the way our climate works.
At least my background in engineering gives me more of an understanding.

How can I put it simply?

When you disturb an under-damped system it will oscillate before resting at it's final value.
The problem is that the climate is being constantly disturbed by:
the Sun
volcanoes
CO2
galactic cosmic rays
and maybe many other variables we know nothing about.

These oscillations hide the underlying data.

An even easier example for you is the Gulf stream -
where you try to warm part of the planet & it fights back
by stopping the gulf stream & causing an ice age in Europe.
That's an example of negative feedback.

A positive feedback would be warming the tundra in Siberia & releasing methane -
a much worse greenhouse gas than CO2.

The 31 page paper I posted the link for goes into a lot more detail and until
Monk can grasp that he's not in the starting line.

The climate has always been changing & it has led to extremes like the maunder minimum -
quite recent in global history.
Another Maunder minimum would be a climate catastrophe
with billions of people dying.

cheers
sir Bobby.