birding-aus

Re: Outback rainfall events and Princess Parrots

To: Ian May <>
Subject: Re: Outback rainfall events and Princess Parrots
From: Laurie Knight <>
Date: Fri, 7 Jan 2011 09:44:32 +1000
The climate maps on the website are summary documents. The fact that a map shows that a region had its wettest year on record does not
imply that every point in that area had its wettest year on record.

What the map does show is that rainfall across Central Australia was
typically in the 9th decile or higher - that is, very wet in relative terms. Similarly the temperature map also shows that temperatures across much of Central Australia were typically in the first decile - very much below the average.

Not only did the princess parrot irruption take place in a wet period, it was also a prolonged cool period. Kakadu, by contrast had both
above average rainfall and temperatures.  I'm blaming that for my
failure to find any WT Grasswrens in August ;)

As for Lake Eyre, virtually all the rivers flowing south from
Queensland carry flood warnings, so there will be further substantial inflows this year.

LK

On 07/01/2011, at 8:36 AM, Ian May wrote:

Hello all


Note the BOM rainfall map indicating 2010 was the wettest year on
record for the area where Princess Parrots irrupted.

see 
http://www.bom.gov.au/announcements/media_releases/climate/change/20110105.shtml

However apart from local anomalies, the information appears to be
not quite correct. Despite the hype surrounding current outback
seasonal conditions, 2010 was not the highest outback rainfall event in recent history. In many areas of Central Australia 2010 was not
even close to the record event it has been portrayed to be. (See
links below)

Why do so many of us often think we are experiencing the wettest/
driest, hottest/coldest, biggest/smallest weather events on record
when a careful study of the daily records from ALL the available
stations show that in only 150 years of records we rarely are?

Sometimes even the Met Bureau misinterprets the available
information.   Is someone pushing their climate change agenda a
little hard? Is there is a selective process in play or is someone careless with their research.

Mostly I blame the media and marketing hype from some desperate
tourism operators who sometimes guild the lily just a bit.   The
flooding of Lake Eyre is a classic example of this. How often do we hear this is a once in a generation event. Not true.

Except during extended drought periods, Lake Eyre takes water from
various tributaries particularly The Neales, Macumba, KallaKoopah
and Warburton about 3 times every decade. The Cooper Creek however
rarely flows into Lake Eyre.  Although it reached the lake in 1989
and 2010, the last time it contributed any significant water to the lake level was 1971, 1974 – 76.

In 2010 although the Lake Eyre tributaries flooded and filled the
Warburton Groove, water barely reached the samphire margins with
only a very shallow cover on the lake surface. When the wind blows
across the lake surface, water moves downwind giving an impression
of flooding but if the wind changes you can be looking at a dry area of lake within 24 hours. By comparison, in 1974 the lake filled to a depth of nearly 10 metres. You can still see the wave cut platforms grooved horizontally into the soft calcareous soils of the Halligan Bay mesas.

Sometimes small area weather anomalies break local records and
clearly the media enjoys making great mileage from this.   Such
localised events are not comparable with great wet events such as
1974 when from January rainfall amounts of more than 40 inches fell over a 3 month period across much of Central Australia north from Port Augusta to the Gulf of Carpentaria, Top End and Kimberley. The whole lot flooded. Lake Eyre filled up backing north into the
Simpson Desert and then backed across the NT border.  The desert
sand dunes became islands where water birds bred in numbers that
defied description.  This resulted in the 1970's waterbird
population explosion and partly helps explain why there has been a
decline of water bird numbers since official counts began in 1983.

In 1974 many outback stations around the Princess Parrot habitats
received rainfall around 1000 mm and more. See Yuendumu, Newhaven, Erldunda etc. Alice Springs also enjoyed exceptional conditions in
those years too.

Interestingly Cyclone Tracy occurred in December 1974.  This was a
separate weather event to the outback flooding that commenced in
January although at the same time the remnants of Cyclone Wanda
flooded much of Brisbane.



See Yuendumu NT
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=015528

See Alice Springs NT
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0015590

See Newhaven NT
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0015611

See Ali Carung NT
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0015502

See Erldunda NT
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0015574

See Arkaroola SA
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0017099

See Blinman SA
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0017014

See Frome Downs SA
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0020006

See Innamincka SA
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=0020006

See Birdsville Qld
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=038002

See Winton Qld
http://www.bom.gov.au/jsp/ncc/cdio/weatherData/av?p_nccObsCode=139&p_display_type=dataFile&p_startYear=&p_stn_num=037051





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