Australia’s Hottest Summer? Maybe Not.

By Paul Homewood

This made news a couple of weeks ago, but I have been waiting for full details from  the BOM:

 image

Australia has experienced its hottest summer on record, according to the nation’s Bureau of Meteorology.

Hundreds of individual heat records were shattered across the country over the past three months.

The warm weather, 2.14C above the long-term average, caused bushfires, blackouts and a rise in hospital admissions.

Wildlife also suffered, with reports of mass deaths of wild horses, native bats and fish.

"The real standout was just how widespread and prolonged each heatwave was – almost everywhere was affected," climatologist Blair Trewin told the BBC.

Temperatures had exceeded the previous hottest summer in 2012-13 by nearly 1C, he added – "a very large margin for a national record".

https://www.bbc.co.uk/news/world-australia-47410366

Naturally the Australian Bureau of Meteorology has blamed it on climate change. But is it quite as simple as that?

Nationally, summer mean temperatures have been about a degree higher than the previous record, as have average daily maximums. On the face of it, that does seem extraordinary.

tmean.aus.1202.55689

tmax.aus.1202.63584

http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=timeseries&tQ=graph%3Dtmax%26area%3Daus%26season%3D1202%26ave_yr%3D0

However, the BOM records only start in 1910, and we know there were severe heatwaves prior to that. So let’s take a closer look at NSW, which also broke the record by a long way this year:

tmax.nsw.1202.32154

One of the longest running temperature records in NSW comes from Walgett, a tiny town in the interior, where temperature measurements date back to 1878. Even now, Walgett is pretty much unaffected by UHI, so long term trends are far more reliable than many other sites.

When we examine the full period of record, a totally different picture emerges:

 

image

http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=36&p_display_type=dataFile&p_startYear=&p_c=&p_stn_num=052026

 

Far from this year being the record, the hottest summer was actually back in 1900. This summer only ranks 5th, behind 2017, 1902 and 2006.

The summers of 1884 and 1901 are also close behind.

In fact, the spate of hot summers recently look little different to those of the early 1900s.

 

On a monthly basis, the only month which broke the record in NSW was January.

 tmax.nsw.01.46310

 

Yet even this month was not exceptional at Walgett, where the hottest January was in 1882:

 

image

http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=36&p_display_type=dataFile&p_startYear=&p_c=&p_stn_num=052026

 

 

A comparison of the daily temperatures in 1882 and 2019, shows that the former were much more extreme, with a high of 47.8C. By contrast the highest this January was 46.4C:

image

http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=122&p_display_type=dailyDataFile&p_startYear=1882&p_c=-541343664&p_stn_num=052026

 

 

The all-time high for any month at Walgett is 49.2C, set in January 1903.

The BOM don’t like people knowing about those heatwaves prior to 1910. They claim that measurements were unreliable before then, yet much prefer to continue using data from the middle of big cities such as Sydney and Melbourne.

Whether older temperature measurements from the likes of Walgett are a tenth of a degree or so out, it is indisputable that those heatwaves did occur, and were extremely severe, as many accounts at the time testify.

 

FOOTNOTE

The weather station at Walgett was situated within the town until 1993, when it was switched to the airport, a short distance away.

There was one month overlap, during which the airport temperatures registered 0.5C lower, seemingly indicating the UHI effect of the old site at the Council Depot.

This is in spite of the fact that Walgett is still only a tiny town, with a population of 2267.

 

 image

https://www.ncdc.noaa.gov/homr/#ncdcstnid=30048243&tab=LOCATIONS

 

What is clear though is that the Walgett of the 19thC, little more than a collection of wooden shacks, would not have had the same UHI effect as today with roads, houses and air conditioning.

In other words, old Walgett is not an unreasonable comparison with the new airfield site, as far as UHI is concerned.

via NOT A LOT OF PEOPLE KNOW THAT

https://ift.tt/2u29TCS

March 13, 2019 at 12:06PM

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: