We have all seen the media beat ups about the “Great Four day Perth heatwave 7th to 10th Feb 2016” – never a mention that that the ever expanding Perth urban heat island UHI might contribute to this event. Credit where credit is due though, the original BoM forecast was pretty good. Unlike their Brisbane and Queensland efforts this year.
Check out the statistics assembled by Chris Gillham in Perth – his website has much information on WA and Perth climate matters. Interesting that Perth Airport temperature data shows the “Great Four day Perth heatwave 7th to 10th Feb 2016” was exceeded by several past events at that site.
I’ve added a few lines at www.waclimate.net/perth-heatwave-2016.html to point out that Perth’s 1933 heatwave had six consecutive days above the old century of 100F (37.8C), which beat the previous five consecutive day record set in 1899.
From 1994 to 2016, Perth Metro 9225 has never had five consecutive days above 37.8C, let alone six.
In the first 11 nights of February 1933, the average minimum was 21.9C, which was 4.7C warmer than the first 11 nights of February 2016 with a minimum of 17.2C.
The 2016 minima in the first 11 nights included 9.9C, Perth’s coldest Feb night since 1935, and the 1933 minima in the first 11 nights included 29.3C, the hottest Feb night ever in Perth and 1.6C warmer than the hottest Feb night ever recorded at Perth Metro 9225 in 2004.
Claims that Perth is experiencing its most extreme summer on record are a bit extreme.
According to ACORN, Perth had six consecutive days of +40C in Feb, 1933. As this data set is ‘world’s best practice’, shouldn’t the BoM be using those figures for comparison?
Good question Ian G – just for interest here is a table comparing Perth ACORN with Perth Regional Office 9034 Raw or CDO = Climate Data Online from
www.bom.gov.au/climate/data/
IMHO CDEO = RAW just tidied up for errors & glitches.
One of the amazing things about ACORN is how the difference with CDO keeps varying every few days. Raises some good questions for the Minister – “best minister”.
Interesting too that Perth ACORN does not use Perth Metro which is the source of last weeks heatwave numbers. ACORN uses Perth Airport.
At the end of Feb the BoM might make a statement on summer – if it is hot enough.
Also, Warwick, according to ACORN, there were eight days of +40C in Perth in the summer of 1933, which beats the supposed record of seven +40C this summer. Is ACORN the standard – or CDO?
The BoM must decide.
The pre 1992 or 1993 site was adjacent to a large irrigated park in East Perth. Irrigation cools the air as humid air has a greater thermal capacity, then warms the air by the water vapour greenhouse effect. Any measurements taken at such a location are worthless IMO. I don’t know if the park was existent in the 1930s. I suspect not.
The BoM in their wisdom moved the site to an, of course, irrigated golf course. Any grassed area that isn’t irrigated in the Perth summer becomes a sandpit. Although the new location is somewhat further away from the irrigation than it was in East Perth.