I was astonished at the candour of BOM in this quote:

“MAXTEMPs at Sydney and Melbourne are found to be increasing, respectively, at rates 0.080 deg C per decade and 0.071 deg C per decade faster than the average temperature at the 73 sites”.

So large cities experience UHI effects at the average rate (for daily maxima) of approx 0.75°C/century. As Belinda Campbell pointed out, the effects on daily minima are better known, and therefore probably greater.

Ergo, the UHI effect in large cities is greater than the total global warming recorded during the past century. Whether the effect is the same in smaller urban areas is not known, but the authority cited by Richard C suggests it is even greater in faster growing towns. And it is notable that BOM purportedly exclude ALL towns with populations above 10,000.

This seems to put paid to the murky paper by Jones & Wang (1992?) which has underpinned all the IPCC temp conclusions for nearly 20 years.

It is the firm opinion of the author that weather, ocean and rainfall patterns are cyclic. They always have been, and always will continue to do so…….And that any dire predictions of continuing & worsening drought in the Murray Darling Basin, and in fact in any region of Australia, are entirely unfounded.

Here’s his website http://landshape.org/about-the-author/
There’s a comment there by Warwick Hughes referring to this page
http://landshape.org/enm/inquiry-into-long-term-meteorological-forecasting-in-australia/

The Committee recommends that CSIRO and the Bureau of Meteorology provide to the Australian Government a report with detailed explanatory information as to why a particular dynamic forecasting model or system was chosen for use in Australia. The report should be completed by the end of 2010.

As Warwick says something to watch for

I’ve only just had the time to take a look at this. Thanks for letting me know about it! Your posts went to the spam folder. The problem was with the large number of links in the post; as it’s a characteristic of spam, it triggers the spam detection software. I’ll investigate to see whether I can exempt posts for particular senders, then it will stop being a problem for you.

I had a quick look at your posts and there seem to be differences between them; I don’t have time to compare them word for word, so identify any duplicates you want deleted and I’ll get rid of them.

If you notice your post vanish in future, do send me an email directly, because I don’t see the spam comments any more. I had to put a stop to it, since the site gets up to 200 – 250 spam messages a day.

Cheers.

Then there is our 64 station review by Hughes and Balling, “Eastern Australia temperature variations 1930-1992″
http://www.warwickhughes.com/papers/eastoz.htm
The page 19 graphic;
http://www.warwickhughes.com/papers/Hbeoz19.gif
sums up changes in mean T and DTR for stations with population ranging from 1000 up to a million and more over Eastern Australia.

As to the BOM paper I’ve picked this up from Warwick Hughes naming of the report (thanks Warwick)

http://ams.confex.com/ams/91Annual/webprogram/Paper184863.html
Wednesday, 26 January 2011
605/610 (Washington State Convention Center)
Harvey Stern, Bureau of Meteorology, Melbourne, Vic., Australia; and B. Campbell, M. Efron, J. Cornall-Reilly, and J. McBride
The Australian Data Archive for Meteorology (ADAM) is used to compare trends in maximum temperature (MAXTEMP) at Sydney and Melbourne with those at other (less urbanised) Australian localities.
By this means, the relative extent to which MAXTEMP increases in those cities can be attributed to urbanisation, the enhanced greenhouse effect, and other causes, is quantified.
The influence of cities on overnight temperatures is well documented. However, their influence on daytime temperatures is less well documented.
Sydney and Melbourne MAXTEMP data are compared with other ADAM data sets and are found to be increasing at a faster rate than elsewhere.
For example, Sydney’s MAXTEMP is increasing at a linear rate that is +0.065 deg C per decade faster than that of Newcastle, whilst Melbourne’s MAXTEMP is increasing at a linear rate that is +0.050 deg C per decade faster than that of Ballarat.
More generally, Sydney and Melbourne MAXTEMP data are compared with ADAM data sets for the 73 Australian localities (excluding Sydney and Melbourne) with at least 80 years of MAXTEMP data during the 100-year period 1910 to 2009 inclusive.
MAXTEMPs at Sydney and Melbourne are found to be increasing, respectively, at rates 0.080 deg C per decade and 0.071 deg C per decade faster than the average temperature at the 73 sites. The probabilities of such large differences occurring by chance is <<0.1% in both cases. That the average MAXTEMPs in the two cities are rising faster than at more rural localities is therefore largely attributed to urbanisation.
For both localities, annual MAXTEMP data are statistically modelled over various control periods using MAXTEMP data at surrounding non-urban stations as input. Thereby, sequences of non-urbanised MAXTEMP can be constructed for the hypothetical circumstance of the cities not being built.
Synoptic stratification of daily data shows that a recent "jump" in the Melbourne series is due to buildings constructed immediately to the south of the site.
In contrast to the current study, Torok's (1996) PhD work identified, and adjusted for, "' jumps in the time series due to non-climatic changes' (and this consequently removed) …urbanisation signals from the time series". Torok's adjustments have been applied to the derivation of the Bureau of Meteorology's high quality data sets (HQDS).
The current study's approach (using ADAM data sets) has been to identify, and preserve, the urbanisation signals in the time series.
As would be expected, MAXTEMP rising trends in the Melbourne and Sydney HQDS (with the urbanisation signals removed) are found to be slower than those in the corresponding ADAM data sets (without the urbanisation signal removed).

Hmmm…what that means in terms of adjustments who knows