2 January, 2017

An end-of-year Australian climate report for 2016

Some extensive excerpts below from an end-of-year climate report by shifty Peter Hannam, environmental reporter for the Leftist Sydney Mourning Harold. In a possible example of a Trump effect, Peter for once mentions "climate change" not once!  Is he losing the faith?

Out of all the weather in the whole vast continent of Austraila, the only extreme weather event Peter could find to mourn in the whole year was a big mid-year storm in Sydney that caused a lot of beach erosion. But storms that cause beach erosion are old hat in Eastern Australia, including places just North of Sydney  like Byron Bay.  Note the following quote:

"Since settlement, the Byron Shire coastline has endured a long history of large coastal storms and coastal erosion and as a result suffered major losses to its dunal system. The properties that lie along Belongil Beach have lost significant portions of their land as the relentless effects of the ocean have eroded away its foredune."

So beach erosion proves nothing. It's routine.

Peter then goes on to temperature, heading his subsection:  "Record breaking heat".  And Peter goes on to give a careful selection of statistics about temperature.  And its all laughs from then on.

The one thing he does not give is the actual maximum temperature for Sydney 2016.  He just says vaguely: "40-degree readings".  But those readings were all in Western Sydney, far from the sea, where it is always hotter.  From what I can gather, coastal Sydney stayed BELOW 40.

He then goes on to say: "Sydney will notch its highest readings since reliable data gathering began in 1858 for each of the main measures: for minimum, mean and maximum temperatures"

Note that date, 1858.  Convenient. You can prove almost anything by choosing your starting point. Watkin Tench in 1790 was at least as good a scientist as many modern meteorologists -- he didn't "interpolate" [guess], for instance -- and he recorded a maximum temperature in coastal Sydney of 108F (42C).  Plus ça change, plus c'est la même chose.

See here and also here for a confirmation of Tench's observations

But the funniest bit of all is Peter's link to a study by dear little Acacia Pepler. I have for many decades had the habit of going back to the original text of anything quoted. And it has been my impression previously that Acacia has got more honesty in her than most BoM personnel -- maybe because she is still a student. And she did not disappoint this time.  She was just using rubbishy models -- as they all do -- but reported a run that others -- I suspect -- would have quietly hidden away.

I give the Abstract at the foot of Peter's eructation.  She actually predicts a DECREASE in big storms!  Pesky! And big East Coast storms are actually Acacia's area of expertise.  So Peter certainly gave me a few laughs today.


The storm was generated by a monster east coast low, arguably the state's most significant weather event in 2016, if not Australia's.

In its special climate statement on the event, the Bureau of Meteorology list the tempest's remarkable features. For NSW, it dumped an average of 73.11 millimetres of rain along the state's coastline, the most ever for a single day for any month, beating the previous high set on January 19, 1950, of 68.89mm.

The scale of this mid-latitude cyclone also stretched further, from Queensland to Tasmania, where it broke the Apple Island's drought with record rains.

Also, to underscore the tropical features of the event, all previous storms approaching the amount of rain dumped on eastern NSW had occurred during summer rather than the start of winter, and were linked to tropical cyclones or former ones.

As with other big natural events, social, economic and environmental impacts have lingered long after the storm. Insured losses alone were about $250 million. It has also laid bare vulnerabilities, particularly for coastal communities, of the more intense storms expected as the climate warms. The challenges facing governments include trying to boost resilience and adaptability for residents in a manner that's fair and foresighted.

While major east coast lows have hammered the coastline previously, such as in 1974 and 1978, impacts are likely to worsen with climate change, researchers including Acacia Pepler, a bureau climatologist and UNSW scientist, have found.

For one thing, a warmer atmosphere can hold more moisture – 7 per cent more per degree of warming – and therefore dump more rain. The impact of storms on coasts will also likely be made worse by rising sea levels, with storm surges riding on a higher base.

Record-breaking heat

For Sydney, 2016 had other noteworthy weather, perhaps none more so than the outstanding warmth even if heatwave peaks weren't as frequent as the summer of 2013-14.

As parts of Sydney closed out 2016 with their first 40-degree readings of the summer, the year's last burst of heat was a fitting end to the city's hottest year on record, Weatherzone says.

Sydney will notch its highest readings since reliable data gathering began in 1858 for each of the main measures: for minimum, mean and maximum temperatures.

For day-time temperatures, the city's average day in 2016 will come in at about 23.8 degrees, and nights about 15.5 degrees, Weatherzone estimates. The bureau will release its assessments next week.

For perspective, it's as if Sydney's average year-round conditions matched those of a typical November.

Compared with long-run average, days were about 2 degrees warmer than normal and nights 1.5 degrees. Should similar anomalies by overlaid on 2016 in future years – an increase within the bounds of projected climate change – year-round temperatures would start to feel like a typical December.

'Persistent warmth'

Looking back over the year, Sydneysiders might be forgiven for thinking 2016 was not a remarkably hot year – the last few days notwithstanding.

The city did set a few high marks, including the hottest April day on record with 34.2 degrees set on the 6th. December 14 was another standout with its warm minimum of 27.1 degrees, the hottest overnight temperature for the month but the second for any month.

But generally few months set new high marks and autumn was the only season to do so for mean, minimum and maximum temperatures. The average of day and night temperatures easily eclipsed the previous high set in 2014 by 0.4 degrees, the bureau says.

SOURCE

Projected changes in east Australian midlatitude cyclones during the 21st century

Acacia S. Pepler et al.

Abstract

The east coast of Australia is regularly influenced by midlatitude cyclones known as East Coast Lows. These form in a range of synoptic situations and are both a cause of severe weather and an important contributor to water security. This paper presents the first projections of future cyclone activity in this region using a regional climate model ensemble, with the use of a range of cyclone identification methods increasing the robustness of results. While there is considerable uncertainty in projections of cyclone frequency during the warm months, there is a robust agreement on a decreased frequency of cyclones during the winter months, when they are most common in the current climate. However, there is a potential increase in the frequency of cyclones with heavy rainfall and those closest to the coast and accordingly those with potential for severe flooding.

SOURCE






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