The Man in the Street

I met a man in the street today. Actually, it was the manager of the block of units that I'm staying in and we met on the footpath just outside the entrance to the units. I was going out, he was coming in. Only a couple of minutes earlier I'd been reading Marc Morano's "The Politically Incorrect Guide to Climate Change" and so it was ironic that the manager asked me about how I coped with Monday's weather.

Monday in Brisbane was very, very hot. Normally I would have stayed indoors but on that particular day I needed to accompany my brother to hospital for an appointment with the oncologist who had supervised his course of radiotherapy. It was truly the hottest day I'd ever experienced in Brisbane and I lived in the city for the first twenty four years of my life.

So how hot was it on Monday, December 16th 2019? ABC News reported that:

Brisbane had been expected to hit 39 degrees Celsius, but the CBD hit 41.2 °C at 1:40pm on Monday, equalling the city's hottest December day on record originally set in 1981. 

So 41.2 °C is the hottest temperature Brisbane has ever recorded. Well, Wikipedia states that:

The city's highest recorded temperature was 43.2 °C (109.8 °F) on Australia Day 1940 at the Brisbane Regional Office.

This is an interesting discrepancy. What's going on here? The Wikipedia article quoted from earlier goes on to say that:

The highest temperature at the current station (is) 41.7 °C (107.1 °F) on 22 February 2004.

To make sense of these conflicting records , I was fortunate to come across this interesting site created by Jennifer Marohasy in which she writes:

There is intense interest in climate change as a cause, but perhaps not enough interest in the quality of the data underpinning all the rhetoric. If we really care about this issue of global warming then we will want to know exactly how much temperatures have really warmed over recent decades. So, we will need to know the equivalence of temperatures now measured using electronic probes with temperatures previously measured using mercury thermometers. 

The Australian Bureau of Meteorology measures temperatures from electronic probes that have not been calibrated relative to the mercury thermometers that were once used. Further, the Bureau makes adjustments to temperatures after they have been measured, recorded and archived in the creation of the new official temperature series, known as ACORN-SAT. These homogenised series are then used to calculate national and global averages. 

Mark Huxley Akin (Huck) has suggested that we just get on and start constructing regional climate indices based on real and unadjusted/unhomogenised temperature series. 

Specifically, he has suggested we use “a good sample of well-sited stations with long histories”, using the analogy of the Dow Jones Average. He writes: 

No one ever tries to establish an impossible-to-define ‘average stock price’— including many stocks of doubtful provenance — and nobody cares. These pre-selected indexes of certain representative stocks, that are then followed over a long time-span, tell investors what they really want to know: how the market moves over time, relative to itself. 

Figure 1: Thermohygrograph 

It is the case that for some Australian locations there are long consistent records through much of the twentieth century. For example, temperature data recorded at Brisbane (station number 40214) are currently publicly available from January 1887 to March 1986. This is one of the longest continuous high quality temperature records for anywhere in the Southern Hemisphere with measurements taken using the same mercury thermometer at the same place every day (although the Glaisher stand was replaced with a Stevenson screen in 1896). 

Problems begin, however, around the late 1980s, when there are site moves and equipment changes. In the case of Brisbane, in order to continue any index beyond 1986, it is going to be necessary to join different temperature series and yet there is no data to quantify the equivalence of the measurements from electronic probes, mercury thermometers and also thermohygrographs (see Figure 1) — that were also used at Brisbane.

This is interesting for two reasons. Firstly, the Bureau "makes adjustments to temperatures" so we are not really seeing the raw data. Secondly, temperatures began to be measured differently in the late 1980s. She goes on to report that:

Since 1996 the Australian Bureau of Meteorology has been transitioning away from the use of traditional mercury thermometers to electronic probes in automatic weather stations for the measurement of maximum temperatures. This is a major change in equipment — a major change in how temperatures are measured — yet when this change occurs the Bureau keeps the same station number and just continues to add to the previous record. 

This is in contravention of its own policies that clearly state that a new station number should be assigned, and that there should be at least three years (preferably five) of overlapping/parallel temperature recordings at the same location.

This parallel data exists for a limited number of stations, but the Bureau has so far not made the data accessible. Much of it is currently held by the Australian National Archive as manual recordings into observation books. The numbers need to be digitised so that we can see whether or not the measurements from the electronic probes are comparable to the measurements from the mercury thermometers.  

After much effort, I obtained parallel data for Mildura – as thousands of photographed records. Manual transcribing of some of the data has established that the current electronic probe at Mildura often records 0.4 degrees Celsius hotter — for the same weather. The first electronic probe at Mildura actually recorded cooler. So, the custom-built probes installed sequentially at Mildura have different time constants. It was only possible to establish this after the parallel data was provided to me, and I began an analysis of some of the manually transcribed data. 

We know that since 1996 the temperature record for the Brisbane airport (station number 040842) actually represents measurements from an electronic probe, not a mercury thermometer. We don’t know what the time constant is for this probe. We do know that there is parallel data available from 14 February 2000; that is temperature measurements taken from a mercury thermometer in the same shelter (Stevenson screen). 

We know that there have been four different probes used at the Brisbane airport site, as shown in Table 1. The Bureau has not published the time constants for these probes. Depending on the time-constant, a probe may be much more sensitive to temperature change than a mercury thermometer and thus record warmer temperatures for the same weather.

Again, there is much of interest here. The parallel data has not been digitised and is difficult to access. Such data would show how much the new temperature-measuring method differs from the old. In the case of Mildura's data, the new method is 0.4 °C hotter. Figure 1 shows a graph, taken from the same website, of the variation in Brisbane's mean maximum temperatures from 1887 to 1985:

Figure 1

Reading what she's written, it's apparent that temperature measuring is not as straightforward as we might think. The ways of measuring temperature change and the measurements, certainly nowadays, are homogenised and adjusted anyway. We've seen that the Bureau of Meteorology contravenes its own policies regarding keeping parallel data sets during temperature-measuring changeovers. In short, it's a bit of a mess and probably deliberately so.

Anyway, to get back to the man in the street. His comment to me about the heat was that he'd read of a scientific study that stated that by 2050 there would be no winters in Australia. Presumably, that would mean that the summers would be so hot we would have to abandon the continent or go underground as the inhabitants of Coober Pedy do. Clearly, the incessant media propaganda has worked on him. The day before I'd spoken to a woman who was a firm believer in climate alarmism and felt that Gaia was angry with humanity for our abuse of the planet. That got me thinking about how this Gaia myth came about but that's the subject of another post perhaps.