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#1478640 - 06/12/2018 16:50 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7637
Loc: Adelaide Hills
Originally Posted By: Petros
Guess most of us will be focusing on whether rains can make it into FNQ over coming days.

Bold -- That would be a technicality...and one I'm prepared to overlook, despite living a world away in SA.

It appears an eastern aspect of the sub-tropical ridge might be assisting said activity [from the Coral Sea] smile .


Edited by Seira (06/12/2018 16:58)

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#1478682 - 06/12/2018 23:48 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Markus Offline
Weatherzone Moderator

Registered: 02/12/2010
Posts: 2230
Loc: Clare, SA
The majority of Australia outside of rain forests and certain small climatic areas such as the sub-alpine areas of Tasmania burned at least once every couple of hundred years.

The aboriginals used to use fire throughout Australia as a method of clearing thick scrub and even forest and by repeated low interval burning could convert it to fertile grasslands which supported larger populations of herbivores and made it easier to hunt. Even in Tasmania it is known they used to do significant annual burn-offs (but important to remember they tended not to burn the same areas over and over every year, instead varying the pattern)

As a natural system, the fire weather conditions and thunderstorms determine how often fires occur. In tropical savannah grasslands of the north it could be every 2-5 years, maybe every 5-10 in temperate grasslands (this ecosystem is for the most part now extinct due to grain farming), woodlands 20-50 years, forests 50-200 years depending on regions, this is a generalisation and I'm going from memory. The important difference was the mosaic pattern that was formed by random fire behavior, it broke up large chunks of forest or bushland into varying levels of succession, reducing the frequency of enormous fires that are so often seen since European settlement. Any long term un-burnt areas acted as biodiversity reservoirs allowing species to make their way back to areas which had had a bad run with frequent fire.

Even rainforest will burn on very rare occasions, maybe every 500-1000 thousand years, who knows, provided the frequency of fires isn't too often for its natural regime pretty well any ecosystem will recover to its former glory given enough time.

Fuel load does increase with the time since burning, not so much in leaf litter which increases in the years after the fire until it reaches an equilibrium as such eventually based on factors such as rainfall in the year previous which influences microbe numbers and fungal activity. The canopy fuel load however will go up and up until it chokes out the lower shrubs and the fuel load may decrease a little, but with increasing levels of larger branches on the ground floor which once again depending on the region can take decades to decompose. At this point the ecosystem contains less biodiversity than it had previously. In an unmodified ecosystem, only relatively small areas of the ecosystem will make it to this point and tend to be patchy. This is why the environmental department attempts to do interval burning as it helps maintain biodiversity. They tell the public it is for fuel reduction as lighting fires is viewed unfavorably by a large majority of the public.

These days we have large areas of forest completely untouched and less biodiversity to utilise these resources it contains. We also have plenty of man created ignition sources. Meaning on extreme fire weather days where you wouldn't see lightning and therefore fires, we have firebugs strategically lighting fires into the densest of scrub, or branches dropping on powerlines, cigarette butts, hay bale spontaneous combustion etc etc...the end result speaks for itself.

logansi has hit the nail on the head, we put out all the small fires on manageable days so when the really bad days come, we have huge fuel loads over vast areas and no hope in hell of stopping the fire.

Anyway, just thought I'd clarify that, I'll cease encouraging off-topic discussion

Also please, enough with bringing global warming/climate change discussion into this thread. It is a BANNED topic.
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#1478683 - 07/12/2018 00:14 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Markus Offline
Weatherzone Moderator

Registered: 02/12/2010
Posts: 2230
Loc: Clare, SA
Originally Posted By: Markus
The aboriginals used to use fire throughout Australia as a method of clearing thick scrub and even forest and by repeated low interval burning could convert it to fertile grasslands which supported larger populations of herbivores and made it easier to hunt.


Should also add they could use this technique to encourage the growth of species useful to them. Some species will only exist for a few years after fire, seed, and then disappear for years or decades until the next fire occurs. They noticed this and burned accordingly depending on what species they wanted and/or where they were in Australia.
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#1478691 - 07/12/2018 07:35 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 2835
Loc: Wollongong, NSW, Aus
Quote:
But the University of New South Wales team was looking for a different culprit, and at the turn of the millennium, a new climate driver was discovered — the Indian Ocean Dipole (IOD).

It worked a lot like El Nino, but on the western side of the country in the Indian Ocean.

Dr Ummenhofer discovered the IOD was an even bigger factor than El Nino in driving long-term Australian droughts.

What El Nino and La Nina actually mean for Australian and world weather

A Pacific Ocean phenomenon with impacts around the world
"The Indian Ocean is as important to Australian rainfall as the Pacific Ocean is," Dr Ummenhofer said.

"When you're looking at prolonged drought periods, particularly the millennium drought or the earlier droughts that Australia has experienced, it's actually more the Indian Ocean that is in an unusual state, particularly Indian Ocean Dipole events occurring in unusual numbers."

Dr Ummenhofer's work on the IOD changed the way drought in Australia is understood and helped propel the climatologist to the top of her field.


Interesting article hot off the press! https://www.abc.net.au/news/2018-12-07/indian-ocean-dipole-dominant-cause-drought/10571802






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#1478697 - 07/12/2018 08:32 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 18719
Loc: The Beach.
Well, well , well.

laugh
_________________________
"water has c.30x the heat capacity of air. Someone drop the penny please for those fixated on the notion that the atmosphere is the driver ( preferably in 3D)".

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#1478708 - 07/12/2018 10:30 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
Going by the Windy site, the EQ Pacific trades are set from a strong and prolonged blow from Nino.3 right through into even the edge of the western quadrant on Nino.4 next week.

MJO now in the Indian, and on its way to Darwin going by model consensus.

Pacific Ocean temps remain in the pattern as has been past 2 months, the waters in the Gulf of Carpentaria have joined Darwin to be equal hottest SST for Indian and Pacific ocean. Makes the Gulf a chance for a tropical storm imo over next week or two.

ENSO is neutral, pressure over Darwin refusing to lift.

All leads to a wet Christmas for vast areas of Aus??

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#1478713 - 07/12/2018 11:58 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Thunderstruck Offline
Lightning man

Registered: 10/05/2001
Posts: 14970
Loc: Seaford Meadows, SA
Vigourous trades...setting up lower pressures over Darwin MJO behaving reasonably well, CHI200 still firmly planting La Nina signature, as it has been doing so for a while now, SST's more El Nino so they couldn't be more opposing if they tried atm. It's a fascinating battle.

TS cool

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#1478715 - 07/12/2018 12:53 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Eigerwand Offline
Weather Freak

Registered: 28/05/2012
Posts: 340
I would think the IOD would have an equal if not greater effect on rainfall throughout mos of Australia. One simple but glaringly obvious factor being the west to east flow of the jet stream. I imagine EL Niño mostly impacts coastal Eastern Aus and QLD. Anyone west of the divide in NSW knows the best rains come as NW cloud bands, spawned off NW WA. Similar for Vic too I would think

When I started the ‘Giant high pressure’ thread back at the start of winter I didn’t know as much about the IOD, but the conditions we saw through winter gave a pretty damn good example of how it works.

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#1478717 - 07/12/2018 13:02 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Long Road Home Offline
Meteorological Motor Mouth

Registered: 08/10/2007
Posts: 8633
Loc: Northern Beaches Syd
Dr. Caroline led some of the lectures in my climatology class back in 2007/08, I gave a presentation about how the PDO is also a significant driver on a bigger time scale. We also did a project where we were asked to model global wind changes over the next 50-100 years based on NOAA and NASA data. Fun stuff, the team is pretty smart too, I definitely listen to whatever they have to say. I'm guessing Caroline spent a good part of the last decade researching the IOD/ENSO.

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#1478743 - 07/12/2018 18:17 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Thunderstruck]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: Thunderstruck
Vigourous trades...setting up lower pressures over Darwin MJO behaving reasonably well, CHI200 still firmly planting La Nina signature, as it has been doing so for a while now, SST's more El Nino so they couldn't be more opposing if they tried atm. It's a fascinating battle.

TS cool


While the Pacific SST grades warm to cool from Nino.4 through to Peru, I dont reckon it matters how "anomalously hot" it currently is. Its about oceanic RELATIVE temperature differences, over multi ocean broad scale, that matters imo.

None of us have offered a credible reason for the SST/tropical convection/atmosphere "un-coupling" that we all have discussed here (with consensus), ...in my opinion, over past months.

There is another factor(s), (or a weird combination of all the common indicators that we all follow) - I suspect its the sun solar variation/planet gravity mixtures - but admit I'm only guessing.

One thing that does fascinate me, is that the Pacific Ocean is portrayed as being anomalously warm right now (against a 1981 - 2010 dataset), according to the measures available to folk like me. But I swear that I swam in 32C waters in the Pacific, at Fiji, this time of the year (presently circa 29C now), back in the early '80's, ...witnessed the thermo reading myself.

Can someone tell me why the SST anomaly dataset isnt say, the average of 1940 - present (surface readings would definitely be available and accurate?)?

Because, to me, our climatic predictions, for this day and age are simply not up to scratch.


Edited by Petros (07/12/2018 18:23)

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#1478753 - 07/12/2018 20:04 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
adon Offline
Meteorological Motor Mouth

Registered: 19/08/2004
Posts: 5331
Loc: Not tellin!
This thread is like the daytime soapy tv. Mike convinced an Elnino is around the corner, kino and others opposed to anything he says, and the odd interesting post. It’s about time people start paying much more attention to the Indian Ocean. I’ve been saying it for years.

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#1478754 - 07/12/2018 20:17 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: adon]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7326
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: adon
This thread is like the daytime soapy tv. Mike convinced an Elnino is around the corner, kino and others opposed to anything he says, and the odd interesting post. It’s about time people start paying much more attention to the Indian Ocean. I’ve been saying it for years.


Indian Ocean didn't seem to do much good for eastern states the last two summers despite delivering record rainfall across the Top End:



I'm not sure if the Indian Ocean has anything to do with the blocking quidge which caused those rainfall deficits either. It's one thing to have an active monsoon over the NW but it's another thing to get it to push eastward.

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#1478755 - 07/12/2018 20:31 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7326
Loc: Maryborough, Wide Bay, QLD
Let me also add that it's nice to see an almost cloudless Indian Ocean on the satpic with all the action over QLD and in the Coral Sea for a change. Hopefully it stays that way for the most part and we get some good troughing through the eastern interior to drag some of that tropical moisture down through drought stricken QLD/NSW unlike the last couple of years. While I'm sure the Indian Ocean plays its part, there are other factors (some imo unknown) on the other side of the country that have prevented it from meaning much in the east.

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#1478758 - 07/12/2018 20:59 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
mammatus meestrus Offline
Weather Freak

Registered: 20/11/2008
Posts: 50
Loc: lennox head
Never does east of the divide, Pacific derived moisture is far more important there.

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#1478761 - 07/12/2018 21:31 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
With the Great Divide, we should all state the regions in E Aus more specifically when we post here.

....not gaving a go at anyone

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#1478762 - 07/12/2018 21:34 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mega]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: Mega
Originally Posted By: adon
This thread is like the daytime soapy tv. Mike convinced an Elnino is around the corner, kino and others opposed to anything he says, and the odd interesting post. It’s about time people start paying much more attention to the Indian Ocean. I’ve been saying it for years.


Indian Ocean didn't seem to do much good for eastern states the last two summers despite delivering record rainfall across the Top End:



I'm not sure if the Indian Ocean has anything to do with the blocking quidge which caused those rainfall deficits either. It's one thing to have an active monsoon over the NW but it's another thing to get it to push eastward.



What was the state of the IOD at the time, in the month preceding that pair of referenced events?


Edited by Petros (07/12/2018 21:35)

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#1478771 - 08/12/2018 01:03 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7326
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: Petros
Originally Posted By: Mega
Originally Posted By: adon
This thread is like the daytime soapy tv. Mike convinced an Elnino is around the corner, kino and others opposed to anything he says, and the odd interesting post. It’s about time people start paying much more attention to the Indian Ocean. I’ve been saying it for years.


Indian Ocean didn't seem to do much good for eastern states the last two summers despite delivering record rainfall across the Top End:



I'm not sure if the Indian Ocean has anything to do with the blocking quidge which caused those rainfall deficits either. It's one thing to have an active monsoon over the NW but it's another thing to get it to push eastward.



What was the state of the IOD at the time, in the month preceding that pair of referenced events?


2016 was strongly negative before winding down at the end of the year.
2017 was moderately positive before winding down at the end of the year.

http://www.jamstec.go.jp/frcgc/research/d1/iod/e/seasonal/outlook.html

Jamstec has achives of such data going back as far as the mid-00s. Just select parameter and year/month dropdown boxes.

Interesting on that page that Jamstec seems to think we're in a modoki-like state atm:

"As predicted earlier, El Niño/El Niño Modoki-like state has actually emerged in October. The SINTEX-F continues to predict a moderate-to-strong El Niño event that reaches its peak in late winter. This El Niño is more or less of Modoki-type and we need to be careful of its impact as it may be different from that of the canonical El Niño."

Though it should be noted that was last updated on Nov 1.

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#1478791 - 08/12/2018 09:18 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
Thanks Mega. Seems to me to reinforce that a set up of one indicator of the past doesn't necessarily mean a repeat in the future (as all here know).......

Heaps of WV streaming into Aus over Geralton at the moment, MJO nearing phase 3 with a slight majority of models suggesting it will make it to Aus and decay here over next 10 days. Pacific ocean trades blowing keenly across all Pacific EQ regions bar doldrums in the southern sector of Nino.4.

Surely the present climatic conditions around Aus will produce plenty of rain, over large yet varied areas, over the next 10 days.

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#1478793 - 08/12/2018 09:26 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7540
Loc: Maffra, Central Gippsland, Vi...
Had a look at that jamstec link Mega, if that prediction (acknowledging it is some 38 days stale) is to come true, there should be quite a rise in SST through Nino1.2-Nino.3, coupled with a fall Nth of New Guinea, ......commencing about now.

That would take a big reduction in the trade winds in the East EQ Pacific, which is certainly not the case right now, nor predicted over coming 10 days by either EC of GFS acc. to the Windy site.

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#1478809 - 08/12/2018 15:04 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: adon]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7637
Loc: Adelaide Hills
Originally Posted By: adon
It’s about time people start paying much more attention to the Indian Ocean. I’ve been saying it for years.

There are probably numerous things we could pay more attention to (the IOD being one of them)...I guess it depends on what gets covered and how.

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