All Scientists are Sceptics ~Professor Bob Carter

Whenever someone asserts that a scientific question is “settled,” they tell me immediately that they don’t understand the first thing about science. Science is never settled. Dr David Deming

Perhaps the most frustrating aspect of the science of climate change is the lack of any real substance in attempts to justify the hypothesis ~Professor Stewart Franks

A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf
A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf
A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf

Tuesday, 20 December 2011

Spin: 2011 to be Perth's hottest year ever

Narelle Towie writing in Perth Now (link) writes:
METEOROLOGISTS say 2011 will be Perth's hottest year in history - our third consecutive hottest year since records began.
Perth's mean daily maximum temperature from January to November was 25.3C, topping the 2010 record of 24.9C, according to the WA Bureau of Meteorology.
"When we factor in the seven-day forecast, for us not to break the record we would have to have average temperatures of less than 20.7C (this month) and we really don't think that is going to happen," bureau weather services manager Neil Bennett said.
Analyst Chris Gilham doesn't agree.

Chris Gilham analyses the data:

They're so keen to promote global warming they can't even wait a couple of weeks till 2011 is finished! Perth's had 10mm above the annual average rainfall and what have seemed showery, cool to mild conditions throughout spring and now into summer, with a little burst of heat at the beginning of December hitting 37.6C. Even Christmas Day looks like it'll probably be less than 30C. Hooray!

The BoM's Monthly Weather Review is at http://www.bom.gov.au/climate/mwr/. This is based on observations from all available years of data at all WA stations with a temperature record longer than 30 years.

Below are WA's monthly readings so far for 2011:

Jan - 29.7C - 1C above average
Feb - 27.9C - 0.9C below average
Mar - 25.3C - 1.3C below average
Apr - 23.1C - 0.1C below average
May - 18C - 0.9C below average
Jun - 15.5C - 0.4C below average
Jul - 15.9C - 1C above average
Aug - 17.6C - 1.1C above average
Sep - 19.6C - 0.1C above average
Oct - 23.4C - 0.2C above average

i.e. the long-term average of the 10 months from Jan to Oct in WA is 21.66C, but this year it was 21.60C. Rounded, WA was .1C cooler than the historic average from January to October. If all of WA is regarded as a climate change guinea pig, the poor little thing is getting chilly. My monitoring of 32 sites across WA found temps fell about .14C in November, so I think the guinea pig might need a blanket. In essence, northern and inland WA has been more below average than the South-West coastal strip has been above average.

OK, much of the Sunday Times story is about Perth, not WA. The BoM states that Perth temperatures spiked in the 1970s and have continued to climb each year, particularly over the past decade and consistent with climate change.

Perth's temperature history began in 1897 atop Mt Eliza (elevation 61m) with the establishment of station 9034 (Perth Regional Office). In 1963 the station was moved about 300m and in 1967 it was relocated about two kilometres to inner city Wellington St, East Perth (elevation 19m). Station 9034 was closed in 1992 and the Stevenson Screen was moved four kilometres north to establish the Perth Metro station in Mt Lawley (9225), with the 9034 historic record adjusted for baseline equivalence for both the Perth Metro and Perth Airport stations. The 9034 temperature chart is:



There's that spike in the 1970s and Perth temperatures increasing by about .7C after the thermometer was moved from the top of Mt Eliza in West Perth to Wellington St in East Perth. It's sort of like Perth's very own hockey stick.

It's worth noting that the only known direct temperature comparison between West Perth and East Perth is within records of the 11 year mean from 1897 to 1907 on Mt Eliza at 63.9F (17.72C) and the same 11 year mean at Perth Gardens (elevation unknown but at Supreme Court Gardens near the Swan River and about the same elevation as Wellington St) at 64.9F (18.27C). That's almost 0.6C warmer at the lower elevation in the same city and the same weather day by day, a similar shift to the Wellington St increase in the chart above.

This is BoM HQ data so obviously the appropriate adjustments have been made to counter the effect of the two kilometre relocation. Hmmm.

OK, Perth Metro in Mt Lawley became the source of Perth's daily weather records as of 1994, covering the past couple of decades of below average rainfall during which almost all of Perth's historic record maxima have been broken. Let's have a look at the three different stations that have recorded the temperatures of "Perth" since 1897:


Thanks to the colder inland minima getting colder (low rainfall and little nighttime cloud cover), Perth's mean temperature has been stable and even dropped a tiny bit over the past 20 years. Yes, it looks like the maxima have been getting hotter over recent years but maybe the Sunday Times opening sentence would be a bit more accurate if it read:

"METEOROLOGISTS say 2011 will be Mt Lawley's hottest year in history - the suburb's third consecutive hottest year since records began in 1994."

As for Perth Airport's High Quality temperature record, this is 9034 data (Perth Regional - Mt Eliza/Wellington St) from before 1992 adjusted to be equivalent with Perth Airport after 1993, as is apparent in the chart below drawn from GISS data.



Like Mt Lawley, Perth Airport temps haven't gone anywhere since Wellington St closed.

Most Perth people would probably rate any day at 40C or more as "hot". It might be relevant to note that throughout 2011 since January 1, there has been only one day which snuck above 40C at Perth Metro - 40.4C on Jan 29. If the BoM's forecast continues to the new year, Perth might have only one day above 40C in 2011. This isn't a rarity but it's interesting looking back at previous years and the number of days that exceeded 40C.

Mt Lawley
2011 - 1
2010 - 6
2009 - 2
2008 - 3
2007 - 6
2006 - 1
2005 - 1
2004 - 4
2003 - 5
2002 - 2
2001 - 0
2000 - 2
1999 - 0
1998 - 4
1997 - 6
1996 - 3
1995 - 1
1994 - 3

Changeover and temps based on Perth Airport
1993 - 2
1992 - 1

Wellington St
1991 - 6
1990 - 2
1989 - 3
1988 - 3
1987 - 1
1986 - 1
1985 - 5
1984 - 4
1983 - 0
1982 - 2
1981 - 2
1980 - 3
1979 - 3
1978 - 5
1977 - 4
1976 - 1
1975 - 2
1974 - 3
1973 - 3
1972 - 3
1971 - 2
1970 - 2
1969 - 3
1968 - 6

Mt Eliza
1967 - 1
1966 - 0
1965 - 4
1964 - 2
1963 - 0
1962 - 5
1961 - 6
1960 - 0
1959 - 3
1958 - 0
1957 - 0
1956 - 4
1955 - 1
1954 - 0
1953 - 0
1952 - 1
1951 - 1
1950 - 5
1949 - 2
1948 - 1
1947 - 0
1946 - 0
1945 - 2
1944 - 0
1943 - 0
1942 - 1
1941 - 0
1940 - 2
1939 - 2
1938 - 0
1937 - 1
1936 - 1
1935 - 4
1934 - 2
1933 - 4
1932 - 1
1931 - 1
1930 - 3
1929 - 1
1928 - 0
1927 - 1
1926 - 1
1925 - 0
1924 - 1
1923 - 2
1922 - 1
1921 - 4
1920 - 2
1919 - 0
1918 - 1
1917 - 0
1916 - 0
1915 - 2
1914 - 1
1913 - 1
1912 - 3
1911 - 0
1910 - 0
1909 - 0
1908 - 1
1907 - 0
1906 - 2
1905 - 0
1904 - 2
1903 - 1
1902 - 0
1901 - 1
1900 - 2
1899 - 0
1898 - 4
1897 - 2

Since 1994, Mt Lawley averages 2.77 days per year above 40C
From 1967 to 1991, Wellington St averaged 2.87 days per year above 40C
From 1897 to 1966, Mt Eliza averaged 1.35 days per year above 40C

If these "hot" days in Perth have increased since 1897/1966 because of climate change and not location change, then it must be accepted that due to climate change Perth has had less annual "hot" days in the last 20 years than it endured from 1967 to 1991. So far in 2011 it looks like "Perth" will have less "hot" days than the annual average for all years since records began.

And to save you counting, Perth has had 218 days at or above 40C since 1897.

As for Perth's unseasonal December thunderstorm rain (the wettest December day in 65 years) being caused by sea temperatures rising 1C in the past 50 years, it's worth checking the BoM's SEAFRAME monitoring of sea air temperatures since 1991, particularly the three WA locations of Esperance, Hillarys and Broome which haven't budged an inch for 20 years ... http://www.waclimate.net/sea/sea-air-temperatures.html

For more detail about the temperature recording history of "Perth", see http://www.waclimate.net/perth-bom-history.html

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