Page 1 of 44 1 2 3 ... 43 44 >
Topic Options
#42457 - 14/11/2007 19:38 The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
More information on the various aspects of the IOD can be found here on the Birchip cropping group website.
Mike Pook's slide show on the IOD, which can be accessed on the panel on the right on BCG's home page.
The accompanying audio is not available.
Birchip is a small country town in the Victorian Southern Mallee.
It has a very innovative and go getting bunch of farmers and researchers and is now known Australia wide for it's innovative agricultural developments.
The IOD presentation listed above was given in early July at the BCG Expo.
There are many slides in the presentation that deal with specific weather and climate items of interest that are relevant to the Victorian mallee farmers.
However there is also much information on the IOD that is of a general interest.
It is interesting to compare the diametrically opposed forecasts between the POAMA model forecast of a negative IOD in October 2007 and the FRCGC model forecast for a positive IOD in the spring 2007.
I hope some of the info in this presentation will be of interest to other posters.

Top
#42458 - 24/12/2007 10:25 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
The FRCGC's Indian Ocean Dipole site or Jamstec site found here, under it's "Seasonal Predictions" page has got the forecast world wide SST's for the periods, MAM, JJA and SON in 2008.
Also listed under the "Rainfall Prediction Exp" is the forecast rainfall trends for MAM and JJA 2008.
Also on the "Seasonal Prediction" page under "E-mail discussions" are the mails where Professor Toshio Yamagata of the FRCGC warned the BOM that Australia was looking at a dry winter in 2007.
The BOM's replies are included where they decided not to issue any warning of a dry winter period because it would cause too much trauma amongst the rural community.
So, a lot of grain growers, rather foolishly basing their seasons prospects on the one lot of very good opening rains in April went ahead and forward contracted grain for sale at harvest for what were good prices in May and June.
The crops turned out to be very poor when Professor Yamagata's prediction of a dry winter came true.
As a result a lot of grain growers have not been able to deliver their contracted amounts of grain and have had to find the cash to cover this non delivery.
And to rub salt into the raw wound, world grain prices rose dramatically, doubling the amount that most of these grain growers had to find.
A few of the most seriously affected graingrowers have had to find over a million dollars to meet their debts from their decisions which could have been much better based if the BOM had made public the probable dry winter forecast from Professor Yamagata.
Another interesting paper titled "Triggering of Positive Indian Ocean Dipole events by severe cyclones in the Bay of Bengal" can be found here.
If you wish to follow the world wide severe weather and cyclone events then the World Meteorological Organization site or the "Tropical Storms Worldwide" site are a couple of sites to watch.

Top
#42459 - 26/12/2007 20:49 Re: The Indian Ocean Dipole and the season ahead.
adon Offline
Meteorological Motor Mouth

Registered: 19/08/2004
Posts: 5038
Loc: Not tellin!
Hey ROM how was xmas for you? :wave: Good to see you have started a thread on the IOD for next year. Very close attention will be paid to this area next year by many eyes!

Just got another computer so have been busy trying to get the bloody thing setup how I like them so have not got all the sites bookmarked yet.

Will be looking at this thread very closley next year that's for sure!

BTW just a comment on your comments about BCG.....Pity it's chairman couldn't take a leaf or two out of the BCG's ideas on sustainable farming. Only 1 day after the last rain, some of his paddocks were taking off in a big way. :rolleyes: Sustainable my butt, more like land pilliager! mad

Top
#42460 - 26/12/2007 23:58 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
Very quiet Xmas for this old geezer and Mother Bear [ cuddly and belts Father Bear over the ears if he gets fresh! "Got fresh" actually as in the past tense! ]
One daughter is in Darwin with her family. Another has an ill member of her family and the lad was off christmassing with his in-laws this year.
I reckon the guys in that outfit that you referred to may have a bit too much on their plates at times to keep an eye fully on things.
We averaged 1.9 t / Ha on the wheat and about .65 t / Ha on the Lentils which is pitiful but with the prices and some more savage cost cutting again, my young bloke will come out just ahead for the first time for a few years.
Wouldn't have had anything much bar for that late rain of about 25mms in early November. It saved our skins from a complete wipe out in our heavy soils.

Top
#42461 - 28/04/2008 10:31 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
Getting a bit desperate when I have to revive a thread that no one seemed interested in!
This is the period when the Indian Ocean Dipole, if it is to become active for this 2008 winter season, starts to organise into the phase that it will follow for the rest of the winter season.
Like the ENSO in the Pacific, an IOD does not appear every year.
The current forecast is for the IOD is for a neutral or weakly positive IOD, a change from the forecast negative IOD of a couple of months ago.
The pIOD is an indicator of a dry winter season in the SE of Australia.
The current Jamstec rainfall forecast for SE Australia is for the JJA period to be average or even a little below average rainfall but the SON period to be above average rainfall.
The reason for reviving this thread is that a tropical storm 01B is developing in the Bay of Bengal.
This storm may develop into a severe tropical cyclone.
In a paper which you may peruse here, the proposition is put forward that the positive IOD's are usually preceded and triggered by a severe tropical cyclone in the Bay of Bengal during the April / May period.
If 01B does develop into a severe cyclone in the next couple of days then for us here in the SE of Australia, it might be a good time to take carefull stock for the future 3 or 4 months until we see what eventuates as far as Indian Ocean SST's and the potential or lack of the consequent north west WV inflows down into our southern weather systems.

Top
#42462 - 28/04/2008 10:54 Re: The Indian Ocean Dipole and the season ahead.
bd bucketingdown Offline
Meteorological Motor Mouth

Registered: 07/02/2008
Posts: 5416
Loc: Eastern A/Hills SA
ROM this one suggests that it is caused by burning of forecasts in Indonesia, and therefore will keep on occurring every year one would think as that is what they are still doing, buring forests "willy-nilly"...though I am not fully convinced, but worth a quick look at anyway! (PS. I see that Mr W Grace has now put a rider on the paper that no endorsement by Grace Research is implied!)
http://www.graceresearch.com/KeithPotts.pdf

Top
#42463 - 28/04/2008 17:41 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
Tropical storm 01B in the Bay of Bengal has now been upgraded to cyclone Nargis.

Top
#42464 - 28/04/2008 17:56 Re: The Indian Ocean Dipole and the season ahead.
roves Offline
Weatherzone Addict

Registered: 02/02/2005
Posts: 1285
Loc: Paringa-Riverland
Thats not good news ROM, so the likely hood now of a PIOD is quite strong or do we still not know enough about it yet. On a bit better note the oceans to the NW show a little warming on todays map.
_________________________
YTD-52mm AVE-260mm

Top
#42465 - 28/04/2008 18:06 Re: The Indian Ocean Dipole and the season ahead.
roves Offline
Weatherzone Addict

Registered: 02/02/2005
Posts: 1285
Loc: Paringa-Riverland
Yea I read an article on that burning BD in a paper somewhere but didn't take much notice, supposibly the correlation is there that when the fires start up that the rain basically stops here in australia within 3 days.
_________________________
YTD-52mm AVE-260mm

Top
#42466 - 28/04/2008 18:49 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
No, it's not good news, roves!
However we should not get to excited until we see how cyclone Nargis develops and even then there will be a great number of unknowns about the connection between Bay of Bengal cyclones and the initiation of a pIOD.
At this stage , I am aware of only one paper on this connection between a Severe Cyclone in the Bay of Bengal and the initiation of a pIOD.
According to one of the Australian Climate research unit's senior researchers, one of the main authors of this paper has a very good reputation in the climate research community.
I should point out that a "Severe Cyclone" is referred to so a low to medium strength cyclone may only have a transient effect on the IOD phase.
This whole subject of the Indian Ocean dipole and the teleconnections that influence it are still in a very early research phase unlike the Pacific ENSO which has bucket loads of money thrown at it since it was first recognised in the very early 1970's.
There are other factors as well.
If a pIOD develops, it would be the third back to back pIOD in a row and I don't think that there is any record of this happening in the proxy records that have been used to map the occurrences of IOD's in the past.
So it will be an extraordinary result if we get another serious pIOD.
The Jamstec spaghetti graph that I have access to through the good graces of John 30 has backed away from forecasting a nIOD and is now suggesting a weak pIOD which will drift towards a neutral situation by around August but Jamstec and other models are also suggesting that the LaNina will continue on through most of 2008 and may even strengthen again later in the year.
This may have the effect of neutralising any weak pIOD that may develop.
There are teleconnections between the IOD and the ENSO which are being researched.
As an example, Darwin pressures are used as the western pole for the forecasting of the ENSO but Darwin pressures, it is suspected, are also affected by the eastern pole of the IOD which is situated SW off Sumatra.
Cyclone Nargis will possibly supply quite a few answers to researchers in the next few days and weeks.
We will know a lot more on whether and how important a cyclone is to the onset of a pIOD in the next few months.
We will know more about the cyclone severity needed if it actually turns out to help initiates a pIOD.

I am still optimistic about the winter season rainfall prospects but the warning is there for SE Australia and we would do well to watch what happens in the Bay of Bengal over the next week or so.

Top
#42467 - 28/04/2008 20:46 Re: The Indian Ocean Dipole and the season ahead.
Carl Smith Offline
Member

Registered: 21/12/2001
Posts: 1042
Loc: Gold Coast
While a severe April-May TC over the Bay of Bengal as one precursor of a pIOD event is interesting, and appears valid during the period studied (except 1990), as we appear to have undergone a significant climate shift in 2007 the rules may have changed, and I would not be surprised to see the observed relation break down.

Lets not count our chickens before they hatch.

Top
#42468 - 28/04/2008 20:52 Re: The Indian Ocean Dipole and the season ahead.
Long Road Home Offline
Meteorological Motor Mouth

Registered: 08/10/2007
Posts: 7365
Loc: Central Coast NSW
yeah i agree.. + weather and climate NEVER follow a specific rule and we've only knew about the IOD for 10-15 years? so i'm gonna wait and see what unfolds first before i start getting worried and crediting the forecasts smile

Top
#42469 - 28/04/2008 20:53 Re: The Indian Ocean Dipole and the season ahead.
Arnost Offline
Weatherzone Addict

Registered: 10/02/2007
Posts: 3565
Loc: Just a bit north of the "coath...
Both FRCGC and NOAA CDC predict that warmer than normal water will remain around the WA coast until the end of the year. If this indeed eventuates, this surely must bode well for moisture infeeds.

There is a connection between the IOD and ENSO - as well as the Antarctic Circumpolar Wave. If I had LOTS of time... I'm chipping away and will share as and when...
_________________________
Exceptions are pernicious, they conceal laws...

Top
#42470 - 28/04/2008 21:00 Re: The Indian Ocean Dipole and the season ahead.
Vlasta Offline
Weather Freak

Registered: 24/01/2008
Posts: 951
Loc: Melbourne Seaford
The things cant get better , the discusion is hot , Al Gore couldnt handle it let alone me lol , I will get to it in the thread of ice age later

Top
#42471 - 28/04/2008 21:00 Re: The Indian Ocean Dipole and the season ahead.
roves Offline
Weatherzone Addict

Registered: 02/02/2005
Posts: 1285
Loc: Paringa-Riverland
Thanks for that information Rom I too are still optimistic for this year although I think an above average year is stretching things at this stage.
_________________________
YTD-52mm AVE-260mm

Top
#42472 - 28/04/2008 22:06 Re: The Indian Ocean Dipole and the season ahead.
adon Offline
Meteorological Motor Mouth

Registered: 19/08/2004
Posts: 5038
Loc: Not tellin!
Would be quite happy with an average one here Roves! I did hear somwhere that there was hope of good rains in spring so if we can make it through winter on one or two rains, we may have a shot at a good year. Though I am treating both predictions as guesses ATM but am getting a little more concerned as time goes on. Still time for a break in May so all is not lost.

Vlatsa don't really get your post. This is thread is pretty free from AGW argument so I think we would all ask you to refrain from making more refrences to the argument. Thanks

Top
#42473 - 28/04/2008 22:17 Re: The Indian Ocean Dipole and the season ahead.
bd bucketingdown Offline
Meteorological Motor Mouth

Registered: 07/02/2008
Posts: 5416
Loc: Eastern A/Hills SA
There is a connection between all the sea currents around the world via the world global conveyor belt which runs right around over and under all ocean areas. Simplistic diagram below:

World ocean thermohaline circulation. The global conveyor belt thermohaline circulation is driven primarily by the formation and sinking of deep water (from around 1500m to the Antarctic bottom water overlying the bottom of the ocean) in the Norwegian Sea. When the strength of the haline forcing increases due to excess precipitation, runoff, or ice melt the conveyor belt will weaken or even shut down. The variability in the strength of the conveyor belt will lead to climate change in Europe and it could also influence in other areas of the global ocean.
Sources Climate change 1995, Impacts, adaptations and mitigation of climate change: scientific-technical analyses, contribution of working group 2 to the second assessment report of the intergovernmental panel on climate change, UNEP and WMO, Cambridge press univeristy, 1996
Link to web-site http://www.grida.no/climate/vital/32.htm
Cartographer/
Designer Philippe Rekacewicz, UNEP/GRID-Arendal
Appears in Vital Climate Graphics
Published 2000
Feedback/Comment/Inquiry Feedback form
Search for other graphics With related subjects
Covering the same geographic area
Use constraints

Using the graphics and referring to them is encouraged, and please use them in presentations, web pages, blogs and reports.
For any form of publication, please include this link:
http://maps.grida.no/go/graphic/world-ocean-thermohaline-circ
ulation

Please give the cartographer/designer/author credit (in this case Philippe Rekacewicz, UNEP/GRID-Arendal) and give full recognition to the data sources used in the graphic.

Top
#42474 - 28/04/2008 22:27 Re: The Indian Ocean Dipole and the season ahead.
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6424
The Jamstec /FRCGC site has the forecast SST's and forecast rainfall trends for JJA and SON in the prediction panels.
FRCGC, ECMWF, IRI and UKMET office are all forecasting pretty well the same scenario.
A bit below average rainfall in the JJA period and then a little above average in the SON period.
We can certainly live with that if we get a good opening rain by the start of June which is late but OK and then some rain to keep the crops ticking along.
Good spring rains during the money months of September and October can give us a very good year.
With my luck we will havve no rain in Sept / Oct , the crops will die and then there will be floods in November!
Viola!! the forecast was spot on! We got good rains in SON!

Top
#42475 - 28/04/2008 23:25 Re: The Indian Ocean Dipole and the season ahead.
Vlasta Offline
Weather Freak

Registered: 24/01/2008
Posts: 951
Loc: Melbourne Seaford
very happy that the CO2 and the 0.1% of extra sun's output was left behind , its the ocean's curents that drive the temperature . Upweling of cold water is the key ( I think ) of the conveyor.Give it a 30% a slow down since 1998 , there must be a follow on effect , must say, not seen in Europe , even opposite , but its only 10 years . Now scientists give it 1 -50 chance it will happen in next decade that northen Europe might drop due to Gulf stream temp. by 1-3C . Hope I dont soud like Al Gore Who woudnt even know why rains falls

Top
#42476 - 29/04/2008 00:19 Re: The Indian Ocean Dipole and the season ahead.
adon Offline
Meteorological Motor Mouth

Registered: 19/08/2004
Posts: 5038
Loc: Not tellin!
http://forum.weatherzone.com.au/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=007093

try this thread Vlasta

Top
Page 1 of 44 1 2 3 ... 43 44 >


Who's Online
12 registered (paul71, slotmachine, T.C Tracker Petar, Andy Double U, Cimexus, Rolling thunder, SBT, iluvrain, 4 invisible), 139 Guests and 50 Spiders online.
Key: Admin, Global Mod, Mod
Today's Birthdays
Karl Lijnders
Forum Stats
27417 Members
32 Forums
21904 Topics
1225402 Posts

Max Online: 2925 @ 02/02/2011 22:23
Satellite Image
Advertisement