Australia and ACORN-SAT

It looks like the folks at Cape Otway and Wilsons Promontory have been having too many gin-and-tonics in those quiet evenings.

Billy liar, that document is an interesting read. Makes you realize how many adjustments are being made and how many are potentially questionable.
This caught my attention,
Figure 10 shows an example of data flagged by this check, a minimum temperature of 20.6°C at
Giles (25°S 128°E) on 11 January 1988. The lowest three-hourly temperatures at the site were
26.2°C at 09:00 the previous day, and 27.5°C at 06:00, while other sites in the broader region
mostly exceeded 27°C. (As there are no sites to the north or south of Giles within 500 km, the
value affects the analysis over a large area). Such differences, if real, would almost certainly be
associated with a thunderstorm at Giles, but no significant rain was recorded there, suggesting
that the value on that day was suspect.
Their thunderstorm assumption is wrong. I can speak from personal experience of the central desert that non thunderstorm forming areas of cloud occur on a regular basis and cause a significant drop in temperature over a short period of time.

kadaka (KD Knoebel) says:
June 29, 2013 at 9:18 am
From jeremyp99 on June 29, 2013 at 4:49 am:
Meta is a prefix used in English (and other Greek-owing languages) to indicate a concept which is an abstraction from another concept, used to complete or add
Metadata is hence data about data
And metaphysics is physics about physics. With metaphysics completing or adding to physics.
=================================================================
Way back when I was studying philospophy, I learnt the origin of ‘metaphysics’ as being ‘beyond physics’. From Aristotle’s works; his writings on the subject now known as part of philosphy coming after those on physical science. (‘meta’ being beyond or after in Attic Greek)
‘meta’ has changed meaning in the last 40 or so years to its current usage

Nick, any change to raw data is an adjustment to the data set. To call some changes Quality control is mere semantics.
As usual, you don’t address the substantive issue. That they are making a changes to raw data based on a clearly wrong assumption. And note, Giles is probably the station that has the largest geographic effect on Australian temperatures.

The BoM document states,
In general, data that were classified as suspect after review were flagged and excluded from
further analysis.
So in the example, I originally gave, I’d assume the claimed ‘suspect’ data was in fact excluded from the dataset.
The example was from 1988 at a professionally manned station with presumably automatic temperature recording. ;What people ‘wrote down’ or potentially misread is irrelevant. And anyway the data are what was recorded, errors and all.

What is meant by the “minimum” and “maximum” temperature?
We’ve had at least two days recently in Auckland, NZ where the temperature at midnight was higher that the temperature at 3pm (Warm previous day, persistent cloud over night and during the day, with a strong southerly during the day to cool things down). If the “minimum” is actually the “overnight low” and the maximum is the “afternoon high”, then you could end up with the minimum higher than the maximum.

I prefer to adjust raw data myself. After watching Hansen adjust temperature data I am absolutely certain that I would want raw temperature data if I were doing a correlation or a proof for some reason. But I would be very careful what adjustments I would use. Let me demonstrate with an example that you can do. Go to Google and input “temperature Washington DC”, select wunderground.com from the list and scroll down to Washington Weather Stations and review the 30 or 40 temperature readings. These are within 25 miles to 50 miles of DC. The temperatures range from 83F to 94F. I have done this same chore for where I live in all kinds of weather/time of day and the differential range is always similar to DC.
The measurement stations are MADIS, RAPIDFIRE and NORMAL. You can click on the name and get time graphs of the data. You can click on those stations with an > at the end and get a full range of weather information.
My point is that one can fool ones self with small adjustments. Looking at the big picture often yields better decisions. I would never do what BEST did, which is to make a mulligan stew by throwing all readings into a pot. I would carefully select perhaps 100 or fewer temperature records around the globe, examine them very carefully for suitability and work with those data sets.
I agree with Wayne, we got side tracked on this one. But thank you very much, Willis. You are a tremendous worker with great ability to analyze data and spot problems.

Giles has been manned since 1956, although only since 1972 by BoM staff. I’ll take your word for it not being automated until 1992.
The issue here is the data is the data. Transcription errors are something else. Trying to find errors in the data as recorded, decades later, just gives free rein to confirmation bias.
The example I gave is arguably an example of this, where an unusually low temperature is removed from the record, for what to me seems faulty reasoning. The problem with confirmation bias, is the people doing it, don’t know they are doing it, and it is devilishly hard to pin down after the fact.

I’ve been looking at “time of observation” issues for several years now, and I cannot come up with a reason why it would produce minimum temperatures higher than maximum temperatures, even with the TOBS causing the pairs of readings to be recorded for separate days, and even if days were missed (unless some very creative infilling methods were used).
For those unfamiliar with the issue, for a long time temperatures were taken with vertical mercury thermometers that had two effectively “ratcheted” markers. The maximum-temperature marker could be pushed up by the rising column of mercury, but would not fall if the mercury column fell. The minimum-temperature marker could fall with a falling column, but would not rise when the column rose.
Generally once per day, the observer would go out to the Stevenson box, record the settings of the maximum and minimum markers, then manually move them to the present height (temperature) of the column, which would allow them to be moved by the column over the next 24 hours.
If the reading were not taken at midnight, and it virtually never was, then the question could arise as to which calendar day the extreme really occurred on. For the 9am readings, the most reasonable assumption (barring other info) was that the maximum occurred the previous afternoon and the minimum occurred the present early morning. This is apparently what the ACORN records did.
But could this by itself explain the “inverted” readings? I don’t see how. Let’s say that on the 6th of the month, the observer notes a maximum of 20C and a minimum of 10C. The 20C max is recorded for the 5th and the 10C min is recorded for the 6th. The markers are reset to the temperature at the time of the reading, which MUST BE between 10C and 20C.
Let’s say a cold front is moving through that day, and the temperature in the next 24 hour period never again gets higher than that at the time of the reading. When the observer comes out on the morning of the 7th, the maximum temperature marker will always read at least 10C. To continue our example, he reads a maximum of 10C, which is recorded for the 6th, and a minimum of 5C, which is recorded for the 7th.
Let’s say that instead, the observer does not make any reading on the morning of the 7th, and his next reading (and resetting!) is on the morning of the 8th. His maximum reading, which is now for the previous 48-hour period, still must be at least 10C, even if the actual maximum temperature for the previous 24-hour period never got as high as 10C.
So to continue our example, our observer notes a 10C maximum and a 0C minimum. The 10C he records for the 6th, and the 0C he records for the 7th. Now he has a gap to fill in the records. It would be extremely doubtful, IMO, if he did not do some sort of interpolation, filling in a max for the 6th of around 15C to go between 20C for the 5th and 10C for the 7th. The same with minimum temperatures.
Fundamentally, though, I cannot construct a reasonable scenario in which either of these effects would lead to a minimum temperature greater than a maximum temperature.