Why is anyone who is sceptical always "coal-funded"? I am sceptical, and am yet to receive any reimbursement. Have I missed some funding application paperwork somewhere?
Of course, alarmist dieties such as Al Gore and Tim Flannery are completely trustworthy, have never uttered falsehoods or exaggerations, and are working for free. :suspect:

A "professional user" (your quotes) may be a researcher, an air conditioning designer, a farmer or one of the myriad data users. It may be one of the private weather agencies. Their suspicions may be aroused enough by an extremely low temperature for them to query it. Or they may have significantly different nearby data from a private station (lots of them around). In any case, a query raised by the user would be checked.
Ask the bureau, I'm sure they'll answer your question.
And like most wild guesses, it would be wrong.
If you expect the data checking to be done manually you're dreaming. There just aren't enough people who can do the checking properly, and even if there were, who would pay them? I certainly wouldn't because it would be a completely inefficient way of checking. As one who did this sort of checking manually back in the day, I can assure you that computer checking is far more effective. The "magic bean" software is Australian written, and is arguably the best in the world. I say that as one who has used it since its inception, maybe 30 years ago until my final retirement a few years ago. Its design is guided very much by the users - the BoM plus virtually all Australian water authorities, some mining companies and a few others - who test the daylights out of it and also specify particular things they want it to do.
It does have range checking, and sure, someone would have set the limits. The limits would be different for each station, or stations in a region, and set by the person/people responsible for that station. The person who wrote the program wouldn't know or care what a reasonable value was, because it's not hard coded. I don't know about the BoM, but normally anything outside the expected range would raise a flag for the data to be checked. I've told you in my previous post what that could result in.

I don't carry any particular candle for the BoM, and have never worked for them, but as I've said, I've had a bit to do with them as both a professional user and data supplier. Sure, occasionally errors will get through. You may never have made a mistake, but most of us aren't that good. To say that because one piece of data is wrong, all data is suspect, is a load of rubbish.

You actually made my points for me.

Thanks.

I suspect not, but I tried to answer your questions.

The OP describes an aberration between real-time data and archived data, however there could differences in how these two figures are derived.

Real-time data could come straight off the sensor, the BoM like doing this kind of thing for public consumption. Unfortunately sensors could easily be affected by many other external factors e.g precisely dropped steaming bird pooh.

Data for archival would mostly likely be generated from a model that takes as input not just the sensor but many other factors including the dynamics of the weather at the time, some statistical analysis, etc with the aim of providing a more accurate value for the wider area rather than just the immediate area around the sensor bulb.

The software was programmed - and presumably remains programmed - to reject what the equipment says is true, and replace it with what someone else decided to program the software to say is true.

It's not a conspiracy theory to point out the fact - because it is an objective fact - that the BOM's opinion as to what is spurious is merely that: an opinion.

And whilst anyone could say, correctly, that whatever temperature the equipment represents as true may nonetheless be untrue as an objective fact, it is equally correct to say that BOM's opinion as to what is a spurious temperature may nonetheless be untrue as an objective fact.

Who knows why the BOM's "quality control" system was set at - 10 minimum for Goulburn. It might have been because the person instructing the programmer liked round numbers. It might have been because the Giant Spaghetti Monster (blessed be the Giant Spaghetti Monster) used a noodly appendage to change the code in the software. It might have been because the person who chose the threshold had dedicated his or her life to climatology and weather statistics and forecasting, and earnestly believed, based on his or experience, that the temperature could never go below - 10 at Goulburn.

It doesn't matter a fcuk what the motivation was: The decision to set - 10 as the 'spurious threshold' was, objectively, a mistake, unless someone can prove that the temperature measured by the AWOS was wrong and the temperature at that site will never fall below - 10.

Which brings me back to the delicious paradox of all this: Nobody can actually prove what the actual temperature was.

If all that happens out of these events is that BOM defends its software and the validity of its "quality control" system, I'm hardly surprised conspiracy theorists draw the inferences they draw.

I'm speculating here, but it's quite possible that the old mercury max/min thermometer was still in place.

I'm not speculating here: Absent evidence of first-hand observation of that thermometer by a person with expertise in the correct reading of that thermometer, and absent first-hand evidence of the calibration and accuracy of the indications given by that thermometer, it's just a tree falling in the forest that nobody heard.

So you don't have trust any temperature reading that you haven't taken yourself from a thermometer you calibrated?

Yeah well LB is getting a tad tedious and that is an unadulterated fact !

No, CO2 is a gas. A "forcing" is the effect from a heating or cooling source.
Er, no, water vapour is a gas. A "feedback" is an effect.

The AGW theory says that "feedbacks" from the increased CO2 will cause an increase in the water vapour concentration, with the new concentration of the latter causing the warming ("increased forcing").

The definition of those "feedbacks" and exactly how they supposedly work is very mysterious. Nobody seems to know - which can be said about most of the "science" in this scam.

The title to this topic is incorrect from the start. All data managers have to manipulate the data since all raw data has issues. The question is why and how.

From the BOM press release I linked to earlier.

"Contrary to claims, the Bureau has not deliberately set limits on the temperatures it records. The Bureau's systems are designed to flag unusually high or low temperatures so they can be checked for veracity before being confirmed."

Perzactly, R 'n' R.

So who, precisely, checked the "veracity" of the Goulburn temperature measurement in this case, and how, precisely, after the "flag" was flown?

A question that demonstrates a lack of understanding of the importance of the points being made.

My level of "trust" depends on the implications of the reading.

Fortunately for you, the same concept applies to matters that determine your guilt or innocence and, if you're on an operating table, life and death.

A person was recently acquitted on the basis that evidence of a critical point of time was merely someone's observation of a mechanical clock on a hospital wall. No evidence was led as to how often the clock was checked against an accurate standard or how much time the clock 'lost' or 'gained' between checks. Two minutes were the difference between guilt and innocence. The prosecution therefore failed to prove the clock was less than two minutes 'out'.

A difference of 0.4 degrees C of a meaurement of your vital signs on the operating table could be the difference between you living and dying.

If I'm checking the tension on the control cables on my aircraft, I'm picky about the accuracy and calibration of the tensiometer I'm using. If I'm checking the tension of the lines of my Hill's Hoist, I don't give a sh*t.

I suppose some people take the view that if billions are going to be taxed and spent based on opinions about what a 'spurious' temperature reading may be, substantial rigour should be put into analysing those opinions and ensuring that temperature readings are demonstrably accurate within a demonstrable accuracy range.

Well it's fortunate then, that the IPCC has written its numerous reports on more than simply the readings from this one weather station.

also from that link.

Fortunately that didn't happen so you can calm down.

Rest assured: I'm calm.

So what did happen? I keep asking who, precisely, confirmed the Goulburn reading, using what equipment, precisely?

If BOM's software if programmed to consider a reading of -10.4 at Goulburn is potentially spurious, who made that decision, on what basis?

What is the level of accuracy of the measuring equipment?

LB, how do you expect anyone here to be able to answer your question, unless they work for the BoM? Even then, why would they put someone's personal details on a public page?

Why don't you ring up the bureau and ask them.

How can RickNRoll assert what "didn't happen", without knowing what did happen.

Rick obviously purports to be precisely the person you describe: A BOM 'insider'.

I should note that I'm not alleging (and haven't alleged) 'manipulation' of data for inappropriate purposes. I'm merely interested in getting an insight into why the delta between aviation forecasts and reality seems to be getting larger.

These days I breathe a sigh of relief when I read "severe turbulence" in a forecast, as the ride almost invariably turns out smooth.

Not so welcome are all the announcements that Centre has to make about amended area forecasts being available. They seem to be increasing. It's almost as if there's some magic beans software that produces ARFORS on Saturday afternoon/evening, all of which have to be changed substantially when reality hits on Sunday morning.

Maybe I'm just perceiving these changes.

You think you will get a satisfactory answer?

Jennifer Marohasy and Lance Pigeon have tried and tried to get satisfactory answers from the BOM on not just this incident, but a range of questions relating to their temperature data handling.

They have not got satisfactory answers yet.

Hilarious. One dodgy YGLB temp reading is the root of the international AGW left green conspiracy. You guys need to take a cold (-10C) hard look at yourselves.

Does anyone know the lowest temp ever recorded at YGLB? Might have something to do with it.

What is hilarious, Duff Man, is your waltzing into this discussion and naively believing it is all about one reading. Do you realise just how ignorant you look?

Rutherglen, Victoria. Remember that name. This is the place where the questionable methodologies of the BOM are at their most apparent.

The BOM do something called "homogenisation" to all the recorded temperature readings. The temperature record then holds "homogenised" readings that are nothing like what was recorded on the ground at the time.

Yes, that's right - the temperature record is no longer a series of raw data readings, but a set of "homogenised" values.

Look at this:

http://jennifermarohasy.com/wp-conte...4.22.55-AM.png
What you see is 100 years of Rutherglen's temperature data. The raw readings (green) and the "homogenised" (red). The BOM do not dispute this data or any of the readings. Does anything look fishy to you?

That graph was taken from this page. Take a look:
Rutherglen - Jennifer Marohasy

While you're there, look at this. More background on other places around Australia where a clear cooling trend, thanks to "homogenisation", has been turned into a warming trend:

https://ipa.org.au/wp-content/upload...Rutherglen.pdf

Yes bolthead: The person who recorded the lowest temp ever recorded at YGLB knows.

It's -8.5 according to this website: Goulburn historical averages, records and extremes But the website says it only covers from 1971 onwards. And it does not say what source it uses for the data.

I recorded -2 F in 1967 using a wall thermometer I purchased on the advice of Joe the Gadget Man, so I guess it's -18.889 C unless someone else has recorded a lower temperature.

FDG, the temperature record at a single place means absolutely nothing in terms of global climate. One data point does not a trend make.

It's way, way more than just "one data point". Have another look at that graph I posted. I don't know how you could have missed it.

I'm referring to the single data point of Goulburn - Marohasy and the IPA are looking at the trend lines of the homogenised data and raw data from one location as if it's significant. Presumably with the intent of using it to discredit the BOM and saying they're manipulating data to support the pro-AGW case.

The temperature trend for a single location says absolutely nothing other than what is happening locally so is of zero significance taken in a wider context.

So why "homogenise" it?

One data point...how many GRIB blocks make up the upper wind forecast? What BOM is doing is "Homogenise" key data sites with long recording history. They then use these sites to adjust across the country to show a warming trend across the entire database. Effectively, BOM will reduce the key temp data to a handful of data points to represent the entire continent. Why one site? Why ANY site? Any thinking person must ask, critically, is the temperature record now trustworthy?

To account for non climate related impacts on the recorded temperatures.

So how did BOM or anyone else work out the existence and extent of the non-climate related impacts on the temperatures recorded in Rutherglen Victoria in the early 1900s?

So what "non climate related impacts" have there been on the Rutherglen site, RickNRoll?

None.

This is why that site is in such sharp focus. Unlike most other sites, it has never been moved. Also unlike most other sites, it has never had an encroachment of urbanisation on it.

So why the warming trend at Rutherglen when the raw data - which would have to be one of the most pristine temperature records in Australia - shows a cooling trend?

Not just non climate related impacts, also measurement methods.

For example, for how long has the Rutherglen station used a Stevenson Screen?

It has a huge gap in it around 1960. So much for 'pristine'.

Climate Data Online

Also, what we know of the history of this site. As AGW was not an issue back then, the importance of tracking all changes and impacts on temperature records were not relevant back then.

Rutherglen weather station

Mmmm ... Thats the very definition of Pristine ... you know ... "in its original condition; unspoilt."

Perfect, would be if there was no break in the data

Anyway, I don't think it's AGW that's made people pay attention, rather it's CAGW. Without the "C" its not worth a bucket of warm spit (with apologies to John Nance Garner).

I think you'll find that people knew the importance of collecting data on temperature, it just that there weren't trillions at stake for the prophets and acolytes of the 21st century's new religion

The phrase "correcting a statistically determined artificial jump in the data" used in BOM's explanation for the "homogeneity adustments" to the Rutherglen recordings is one of the starkest examples of circular self-justification I've read for long time.

And I'm someone who accepts a causal link between climate change and human activity.

It's no wonder the conspiracy theorists jump on this kind of nonsense. "Statistically determined" just means the output of a model based on someone's assumptions based on opinion. The extent of the "correction" will have been based on someone's opinion.

Another completely circular self-justification: "As AGW was not an issue back then, the importance of tracking all changes and impacts on temperature records were not relevant back then."

We have come to the conclusion that there is AGW. We do that on the basis of records. But some of those records have an "artificial jump" which we found as a consequence of a statistical model. We therefore have to "correct" those records. The "errors" were there because the people who made the records did not know about AGW. Once "corrected", the records support the conclusion that there is AGW.

Is there any point to this thread?

The OP posted;

The Golbourn AWOS reports the real time temp of say -10.5 deg C. I see it sitting at my desk. several days later i look at the temperature records and see that the lowest temp on that day has been adjusted to something like -9.0.

These were made up examples, not actual readings which have lead to over six pages and over one hundred posts for a fictitious 1.5 degrees.

You're not compelled to read it, you know.