The Australian Temperature Record Revisited Part 2: Regional Effects

In my last post I showed how a numerical near-balance of adjustments to the ‘raw’ minimum temperatures at 83 out of 104 Acorn sites resulted in a 66.6% increase in warming trend across the nation.

I now turn to the effect on state and regional temperatures, which is enormously varied.

Figure 1 shows the official BOM trend map of trends in minima from 1910 to 2013:Trend map min

Note the little “bulls eyes” in various places, indicating where the local trend at individual sites is out of sync with the wider trend.  I’m sure you can identify Tibooburra in north western NSW, Richmond in northern inland Qld, Rutherglen in Victoria, Marree in northern SA, and Carnarvon on the WA coast.

Figure 2 shows the median position of all 104 sites, the four unequal area quadrants, and the number of sites I analysed in each with the increased warming resulting from adjustments.
Median network position map adj results

The concentration of Acorn sites in the south east of Australia, and the concentration of warming adjustment there as well, is plainly obvious.

Now I shall show each quadrant in turn, showing the trend difference at each site.

Figure 3:  South west Quadrant sites:
Bar graph SW Quad

Figure 4: SW Quadrant minimum temperature trends:SW quad chart

Figure 5:  North west Quadrant sites:Bar graph NW Quad

Figure 6:  NW Quadrant minimum temperature trends:NW quad chart

Figure 7:  North east Quadrant sites:Bar graph NE Quad

Figure 8:  NE Quadrant minimum temperature trends:NE quad chart

Figure  9:  South east Quadrant sites:Bar graph SE Quad

Figure  10: SE Quadrant minimum temperature trends:SE quad chart

In the next section I look at how the adjustments affect the mean minima in each state.  First I’ll look at the Northern Territory, which is atypical and based on only three sites (Alice Springs, Victoria River Downs, and Rabbit Flat), the two last with less than 50 years of observations.

Figure  11:  Northern Territory- cooling reversedNT Chart

Figure 12:  South Australia- adjustments result in less warmingSA chart

Figure 13:  Tasmania- adjustments result in less warmingTas chart

Figure 14: Western Australia- 23.7% increased warming.WA chart

Figure 15:  Queensland- 37% extra warmingQld chart

So far, every state has seen an increase in warming much less than the national mean of 66.6%, so much depends on the final two states.

Figure  16:  New South Wales- 245% extra warming!NSW chart

That is pretty amazing, but the result for Victoria is even more astounding.

Figure 17: VictoriaVic chart

The implications for the trend map in Figure 1 are obvious.  One hopes that those adjustments are well and truly justified!

In the next post I will discuss the remaining 21 sites which I am unable to compare directly, and later, the trend outliers.

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4 Responses to “The Australian Temperature Record Revisited Part 2: Regional Effects”

  1. Ian George Says:

    Wonderful research here, Ken. Has the BoM been shown this?
    I wonder if you can help me understand something. BoM reports that Australia’s mean temp has increased 0.9C over the past 100 years.
    I ran the 30-year average for Aust mean temp from 1911-1940 (-0.33Cpa) and compared it to the 1984-2013 mean average (0.33Cpa).
    Wouldn’t this mean that the temp rise is more like 0.7C rather than 0.9C?
    (I took the 30-year interval as this is the period used by most agencies as a climate determiner).

    • kenskingdom Says:

      Thanks Ian. The 30 (or 40) year period is the minimum regarded as useful for determining climate TRENDS, rather than means. Anomalies are calculated from the 1961-1990 mean as a standard for comparison, but that can also be misleading as BOM does not calculate the mean of 30 years but the mean of any years in this period even if the majority of values are missing: the minimum number of values used by Acorn is 12 years. I have no confidence in any calculation of historical means before the satellite era, or temperature trends.

  2. Ian George Says:

    Thanks Ken but I’ll be honest – I’m not sure what that means. If I look at Casino, I see that the period from 1971-2000, the annual mean was 26.6C. The period from 1981-2010 is 26.3C. Therefore i would conclude that the average mean p/a has reduced 0.3C.
    If one looks at the overall graph for Casino, the temps do look as if they have dropped. In fact, I read a report in the local paper that the BoM acknowledged that temps have dropped across the North Coast (NSW) in the past 50 years.
    I realise you use the satellite record than the w/s data. Do you have the relevant sites to check the data for Australia?

  3. My Submission to the BOM Review Panel | kenskingdom Says:

    […] further information and full explanation see… […]

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