Category Archives: Urban Heat Islands

50°C in Sydney region 1939 – perspective on recent heat

Last Sunday 7 Jan 2018 Our ABC reports the BoM – Sydney hits its highest temperature recorded since 1939 with Penrith reaching 47.3C. The BoM had just belatedly found that RICHMOND RAAF 067033 hit 47.8 on 14 Jan 1939. But there is much more to the history of hottest days in Sydney. There was another site recording at Richmond in 1939; John Tebbutt’s historic Observatory which recorded 122°F or 50°C on 11 Jan 1939 as reported in the Windsor and Richmond Gazette Fri 13 Jan 1939 Page 3 Sweltering Week Sets New Hawkesbury District Record.
In Jan 1896 there are a multitude of reports of a stunning and deadly NSW heatwave summarized by Lance Pidgeon at JoNova and picked up by the UK Daily Mail – How a 24-DAY heatwave on Australia’s east coast in January 1896 saw temperatures climb to 49 degrees and killed 437 people. The Windsor and Richmond Gazette for Sat 18 Jan 1896 Page 6 Hawkesbury Heat – On Monday 13 Jan 1896 John Tebbutt’s Observatory recorded 118.8°F or 48.2°C – also well clear of the 47.3 at Penrith last Sunday. There is a report in The Daily Telegraph Sydney,
for Tue 14 Jan 1896 Page 5 123 IN THE SHADE AT CAMDEN. But we have no information re the thermometer exposure. I wonder what readers can find. The upshot seems to be that the 47.3 at Penrith last Sunday was only a run of the mill very hot day for the Sydney region. And even less notable when you take into account the ever growing urban heat island and the fact that Penrith records one second intervals in a modern electric AWS which must produce hotter spikes than a slower acting mercury in glass thermometer.

BoM says Hobart October 2017 was the warmest ever

But the BoM fails to say that outside the Hobart urban heat island (UHI) record warmth is harder to find.
I checked the following stations around the Hobart region – first the mean monthly max – only Tasman Island agreed with Hobart but the site has only operated from 2002.

then the mean monthly min gives a similar result.

So the BoM should have told the ABC that although central Hobart had a record warm October – few other sites in the district confirmed that so on balance you would assume that the UHI effect has been quietly ramping up warmth in Hobart data for a ~century.

Blenheim monthly temperature trends show classic urban heat island (UHI) signal

Warming trends showing up strongest in the cooler months. Data is from a Govt fruit research institute the Marlborough Research Centre on the town outskirts. Charts by the MRC. Blenheim population growth. Small town temperature data – often classed as “rural” in global databases – can usually be shown to be riddled with UHI warming.

Click for monthly charts – January — February —March —April—MayJune—July—August—September—October—November—December
Here are the monthly trends in degrees C as per MRC.
Trends 1932 to 2011 or 2012.
Jan ~0.4
Feb -0.06
Mar 0.25
Apr 0.23
May 1.84
Jun 2.03
Jul 1.78
Aug 1.83
Sep 1.28
Oct 0.71
Nov 0.37
Dec 0.02

BoM fiddling Goulburn minimum temperature 2nd July 2017 reveals extent of errors in BoM AWAP temperature maps

Minus 10.4 degrees C was recorded originally at GOULBURN AIRPORT AWS (070330) which was filed by blogger Lance who noticed the BoM rapidly altered this to -10. Jennifer Marohasy blogged on the issue 4 July and passed the info on to a journalist who asked the BoM if they could explain. BoM said they have a “QC” auto function clipping off extremes in case there are errors. And this caused the reset to -10°. JM blogs again on 5 July. This revelation of raw data trimmimg is brand new to many of us who monitor BoM data – but OK thats what the BoM says happened. Jo Nova is also onto the issue. Lance and I checked BoM AWAP maps for NSW daily minimum temperature and noticed the contouring was hugely in error when checked against actual minimums. I have NSW daily minimum temperature maps offline for the 1st July – 2nd July and 3rd July. Just looking at data from the Southern Tablelands region (the white O circles the Goulburn and Canberra localities.) Goulburn is in the wrong contour zone all 3 days. Canberra Airport should be well into the -6 to -9 zone on all 3 days – yet it is always plotted on the boundary of the -3 to -6 and -6 to -9 zones. Always wrong. Taralga about 40km NNE of Goulburn (approx marked white T) read -7° on the 1st & 2nd yet the correct -6 to -9 degrees zone boundary is way too far west on those days. Yass recorded -8.7 on the 2nd yet the contouring has Yass in the next warmer zone. Likewise Cooma on the 3rd should be in the -6 to -9 zone but is shown in the next warmer zone. I expect readers might find errors in other parts of the State – or in other States
With so many errors I wonder what purpose these maps can be fit for. On the issue of the BoM clipping sub -10° readings back to an even -10. Lance mentioned to me these very cold reading from Goulburn Aero Club 70210 in July 1971 – down to -13.9°. Cop that 14 days of frosts in 1971!! Worth noting too the all time coldest Canberra Airport min was -10 on 11 Jul 1971. So setting -10 as an alarm was somewhat odd and without sound scientific foundations – but Hey!! it is the BoM.

New BoM Adelaide West Terrace site warmer at night than Kent Town

I blogged over two years ago on the BoM moving their main Adelaide weather instruments site from Kent Town to West Terrace not far from where the site was from the 1800’s up to 1979. In April 2015 I said – Bureau of Meteorology delusions about the urban heat island revealed in news of relocation (again) of Adelaide weather instruments – And now we see West Terrace is starting its new life warmer at night than Kent Town – assuming the BoM have had time to iron out any instrument faults – there is a gap of 4 hours at West Terrace on the 15th. If readers wanted to do any night time vehicle/temperature traverses – data might be interesting.

Link for larger chart

BoM trumpets January the warmest month on record for Sydney

The BoM blah-blahs on – Every station in the metropolitan area recorded its highest January mean temperature on record and most stations (including Sydney Observatory Hill) also broke records for mean maximum and minimum temperatures.
Not a word on the above BoM page of the ever growing urban heat island driving temperatures hotter for 150 years.
I see Richmond RAAF 67105 had Jan 2017 mean max = 34.1, mean min = 20.
I only have to check historic monthly mean max and min for Richmond – UWS Hawkesbury 67021 to find that 1946 equalled the Jan 2017 max of 34.1 and smashed the min by a whole degree. So obviously all the BoM claims for last month are rendered so pathetically tenous and lineball (without plugging in a “correction for UHI”) – what a disgusting propagandist organization the BoM has become.