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#984723 - 16/04/2011 23:08 Re: The Southern Annular Mode [ SAM ] [Re: Arnost]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
I think you are rather seriously overrating me with your comment on my supposed knowledge on the SAM, Arnost.

Anyway from Bob Tidsdale Nov 2010 if those interested don't already have them, Long term index for the El Ninos / La Ninas from 1900 to 2010

And one on the Southern Ocean from Bob Tisdale August 2010; >On Liu and Curry (2010) “Accelerated Wa...le and Sea Ice”

Bob Tisdale's conclusions on this paper;
Quote:
The title of Liu and Curry (2010) “Accelerated Warming of the Southern Ocean and Its Impacts on the Hydrological Cycle and Sea Ice” contradicts the SST anomalies of the latitudes used in the paper. The SST anomalies are not warming. They are cooling and have been for more than a decade.

Read the linked Willis Eschenbach's take on WUWT on this paper as well.

This above post is rather interesting as well down the post Bob T has some of his usual graphs that indicate the Southern Ocean which he also believes is a starts at much lower latitudes ie; closer to the equator than the International Hydrographic Commission's definitions, illustrates the fall in the SST anomalies from about 1997 on when the SO's SST anomalies hit their peak just before the 1998 super El Nino.
If we do accept that possibly the Peru current up the west coast of South America is transporting a lot of SO water into the South Equatorial current that swings westward just south of the Equator then the time delay of near a decade might be a reasonable time frame for the injection of a huge mass of SO water into the El Nino / La Nina system.
If, a big IF as I haven't seen this anywhere before, this is roughly the case, we may be looking at an extended period of strong La Ninas interspersed with a few weak El Ninos as that SO water keeps cooling and the Peru Current continues to transport all that lower ocean heat energy north into the equatorial regions.
Guessing only but I wonder?

And note just how little actual hard data exists for the Southern Ocean and the lengths that the climate data manipulators will go to to "infill" data where no data of any sort exists and this in the 4th largest Ocean included above the 60 degrees latitude and if you go to around the 50 degree mark it would be the third largest ocean behind the Pacific and the Atlantic Oceans. And all that is just right there about 200 kms to the south from where I am and about 100 kms south from some 4 million Australians here in the SE of Australia.
And we know sweet nothing about that immense ocean that we swim, fish, surf and play in.
I'm one of those who believe water is good for washing in and it does have some other uses.
Some believe it has it's best use is when added to some certain fermented beverages although the salt content rules out Southern Ocean waters for that!

And one that anybody interested in the El Nino / La Nina should look at with it's animation panels again from Bob Tisdale is ; >La Niña Is Not The Opposite Of El Niño – The Videos

A Tisdale post on the An Introduction To ENSO, AMO, and PDO — Part 3 provides a lot of basic explanation on the differences and why and how.

For those who are still trying to figure out how all this El Nino / La Nina stuff works and how and why it affects the global weather and atmosphere well if you want to really get a handle on it here is some heavy reading but you will know a darn sight more than most if you read this and make the considerable effort to try to understand it.
La Nina Events Recharge The Heat Released By El Nino Events AND

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#984739 - 17/04/2011 01:27 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
S .O. Offline
Weatherzone Addict

Registered: 31/01/2011
Posts: 1540
Loc: Southern Victoria
Arnost ,

Yes , This is quite detailed .

Note it generally has a leaning to the actual Atmospheric forcing of the SAM by the ENSO .

Where as I had the Tropical SST's Of Pacific ( and further fetched " The Indian" influencing The SAM via ACC ( Antarctic Circumpolar Current ) .
Which I postulate inturn is the most significant influence to the ENSO . Via the circular Oceanic path that compliments both the Walker circulation and the Hadley circulation .

Within the previous post by Arnost .

" Quote :

Regardless, both studies agree on the distinct changes between the 1980s and the 1990s. Recently, Bromwich et al. (2004) identified significant shifts in the position of convection and the associated amplification of the PSA wave train in December–February (DJF) in the late 1990s El Niño − La Niña difference versus the difference between all other El Niños and La Niñas from 1979 to 2000.
*Thus, there appears to be strong decadal variability of the ENSO signal in the South Pacific; however, the mechanisms forcing the variability remain undetermined. Quote" .

This part shows that there is still many uncertainties .

There is reference to SST's via " Mo (2000) paper ' with this part .

"Quote:

In a study by Jones and Widmann (2004), a SAM reconstruction based upon sea level pressure observations from 1905 to 2000 shows strong positive and negative trends in the middle of the record that do not match any trends in stratospheric ozone or greenhouse gases. Thus, they claim that natural forcing factors, such as solar and volcanic variability, and internal processes in the climate system can strongly influence the variability in the SAM.

There is also some support for the SAM being modulated by tropical SSTs. Mo (2000) regressed the scores from her EOF1 (which represented SAM) on SSTs and found that the SAM is linearly related to the tropical SSTs, similar to the correlation seen here between the SAM and the SOI. To examine the decadal variability in this relationship, the SON SAM was regressed onto the SON SST anomalies between 45°S and 45°N in a similar manner to Mo (2000). The regression coefficients were then multiplied by the change in SST at each grid point to represent the changes in SAM explained by the SST changes. The SST data were obtained from the National Oceanic and Atmospheric Administration (NOAA) extended reconstructed Reynold's SST dataset made available by the Climate Diagnostics Center (CDC, available online at http://www.cdc.noaa.gov/cdc/data.noaa.ersst.html). The changes significant at >95% confidence level are displayed in Fig. 12a for the whole time series and for the two decades individually (Figs. 12b,c). The overall results (Fig. 12a) do not demonstrate any large areas where changes in the SST are related to changes in the SAM, a finding that also exists during the 1980s (Fig. 12b). This is expected and verifies the fact that no significant SAM events occurred with the significant ENSO events during this decade in SON. The 1990s (Fig. 12c), however, are much different in that there is a strong and significant relationship (>95% level) between the SAM and the tropical and subtropical Pacific SST anomalies that extend into the eastern tropical Indian Ocean, unlike that seen in the previous decade. Interestingly, the changes in Fig. 12c are spatially arranged in a prominent horseshoe pattern similar to the SSTs anomalies seen during a La Niña event. Notably, during the 1990s (Fig. 12c) the southern branch of the horseshoe pattern is well marked. Terray and Dominiak (2005) relate this southern branch of the SST horseshoe pattern to the enhanced upper-level convergence brought about by the modulation of the regional meridional Hadley circulation. This upper-level convergence is associated with an upper-level low, which acts as a Rossby wave source region for the associated PSA pattern. From Fig. 12c, the negative (positive) changes in the equatorial and subtropical (western) Pacific suggests a weakening of the SAM during times of warm (cold) SSTs in this region (i.e., El Niño conditions), in agreement with the positive correlation between the SAM and the SOI in the 1990s. Terray and Dominiak (2005) demonstrate a reduction in speed of the polar front jet in the South Pacific associated with the ENSO SST anomalies that also confirms the link between the ENSO and the SAM. Quote" .


And further

" Quote:
Although the regression analyses do not explicitly show a cause and effect relationship of the tropical forcing on the high-latitude circulation due to the simultaneous correlation of the SOI and SAM, they do clearly demonstrate the decadal variability in this linear relationship. Partial correlation analyses do not show any connections of the SAM with the tropical Pacific SSTs; however, this statistical method only examines the linear connection with the residual variability after the cross correlation is removed. Because of the strong covariance between these two time series, the residual part of the SAM not explained by the SOI is small, and is also unlikely to depict the actual physical variability in the SAM.

Recently, a modeling study conducted using version 2 of the NCAR Community Atmosphere Model (CAM2) model confirmed the tropical SST forcing of the SAM (i.e., Zhou and Yu 2004). They also noted a significant relationship between the SAM and tropical Pacific SSTs in austral summer, where warm tropical Pacific SSTs lead to negative phases of the SAM, giving further credence to the significant positive correlation seen here between the SOI (<0 when Pacific SSTs are warm) and SAM during this season. Quote ".

And this is already shown for the Indian - North Atlantic ???? .
"Quote:
Although the concept of the tropical SSTs forcing the SAM may be questioned in the SH, similar connections have been established in the NH. Hoerling et al. (2001) using both observations and an atmospheric general circulation model (AGCM) show that the North Atlantic Oscillation (NAO), which is alternatively termed the Arctic Oscillation or Northern Annular Mode (e.g., Thompson and Wallace 2000), is related to tropical SSTs in both the Pacific and Indian Oceans. Their study argues that the observed boreal winter trend in the NAO is intimately linked with the warming in the tropical SSTs, suggesting that the SSTs are forcing the NH extratropical climate. Their earlier work was later updated by more modeling experiments where they further conclude that the tropical Indian Ocean SSTs significantly modulate the NAO (Hurrell et al. 2004; Hoerling et al. 2004).

The exact mechanism controlling the coupling needs further study, and many questions remain unanswered. Examining the role of the meridional circulation across the Southern Hemisphere in relation to the SAM and ENSO variability might help to unlock some of these answers. Additional modeling work, both regionally and globally, can help to demonstrate nonlinear components that lead to the coupling, especially since Hoerling et al. (2004) find that the NAO is strongly modulated by nonlinear atmospheric processes arising from the increasing tropical Indian Ocean SSTs. Quote " .

And after all this good work ( and including " Empirical " methods EOF ) ,
they manage a summary ending with this : -
"Quote:
The results presented here, in combination with a growing body of literature, suggest that tropical ENSO activity plays an important role in the forcing of the high southern latitude tropospheric circulation. It is unclear whether the coupling observed here between the high-latitude SH circulation and ENSO is part of natural climate variability or climate change; the quality of the available reanalyses limits the study to roughly the last two decades. However, the associations depicted in the 1990s are the strongest observed during this time period, in agreement with other recent studies (e.g., Bromwich et al. 2004). Quote " .

As i've mentioned before , these Types of papers really annoy me that they can be linked to AGW and show agreeance , when the line above them
( second last line ) postulates uncertainty and really should be showing more emphasis that this is a very Short term study and even at that gives significant rise to Natural Decadal variance . !!!! Perhaps as mentioned elsewhere payment is dependant on correlation to a trend . ( ie AGW = pays! )

Anyhow now to study " Mo 2000 " .

Night .
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#984742 - 17/04/2011 02:03 Re: The Southern Annular Mode [ SAM ] [Re: S .O.]
S .O. Offline
Weatherzone Addict

Registered: 31/01/2011
Posts: 1540
Loc: Southern Victoria
Further reading
"link"
"http://www.agu.org/pubs/crossref/2009/2009JD012657.shtml"

and far reaching ?
" link"
"www.agu.org/pubs/crossref/2003/2003GL018381.shtml"

And tomorrow Bob T . will get a look , " in between entertaining an 8mth old ". LOL
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#984911 - 17/04/2011 22:11 Re: The Southern Annular Mode [ SAM ] [Re: S .O.]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
I am coming to the conclusion that a separate category should be created in the Forum to cater for the various global climate and weather controlling systems to be discussed and dissected.
Items such as the SAM thread, the IOD thread , the ENSO thread , the polar vortex and Sea Surface temperatures could be collected under the one forum heading so that if a thread is seasonal like the IOD thread it does not get lost amongst all the other threads.

Anyway Judith Curry has another real interesting thread going in her blog "Climate Etc" titled "Scafetta on Climate Oscillations"
A quote of interest here as this as been discussed and suggested only days ago here on this forum, and I haven't seen this before, comes from a commenter Chief Hydrologist who also has a site Earth and Oceans where he enlarges on the various ocean interactions and influences
From the Chief Hydrologist post in the Climate Etc blog.
Quote:
Here is an SST anomaly thermally enhanced satellite image from December last year.

http://www.osdpd.noaa.gov/data/sst/anomaly/2011/anomnight.4.7.2011.gif

You can see the PDO in the north Pacific and La Nina in full swing in the central Pacific. You can also see the potential for cold water being pushed up from the Southern Ocean and onto the western coast of South America in the area of the Humboldt Current. The region of the Humboldt Current is the most biologically productive area on Earth because the cold southern water is joined there by upwelling frigid water. The upwelling (or not) in turn determines the thermal evolution of ENSO. ENSO is many things but starts in upwelling – or not – in the eastern Pacific.

There is a direct physical link between UV and the SAM in the ozone layer of the middle atmosphere – and thus in storm tracks spinning of the Southern Ocean, pooling cold water off the western coast of South America and diluting the warm surface layer that suppresses upwelling in the eastern Pacific.


This post on Scafettas work has everything.
The influences of the planets and the cycles and how those cycles are showing up in the climate data records, Ocean current influences and interactions between oceans, the PDO, IOD, ENSO, solar UV rays and the so called ozone hole and it's effects on the SAM and that is all in the the post plus a brief browse in the comments are showing even more very good info on this whole Ocean / Climate interactions.

I've got some reading to do, some of it heavy, over the next few days.


Edited by ROM (17/04/2011 22:14)

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#989371 - 13/05/2011 20:23 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
Big_Pete Offline
Weatherzone Addict

Registered: 19/12/2004
Posts: 1955
Loc: Perth
Hey ROM, I read the thread right through, just wanted to know something? Will the negative SAM index mean more cold fronts this winter for Southern Australia?

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#989377 - 13/05/2011 20:51 Re: The Southern Annular Mode [ SAM ] [Re: Big_Pete]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
The answer to that one is that in all likelihood yes as research out of Argentina and now some out of Australia all indicate that when the SAM / Antartica Oscillations are in a long term negative phase [ they switch around every few days but do have long term trends which have been basically positive since about 1990 up until the last year when the SAM started to show the probability of a long term negative trend ] then the southern lows and their associated fronts are pushed north as are the highs so more intense cold fronts but not necessarily more cold fronts as the centres of the lows move north with a negative SAM.
And with that move of the low centres north, colder air behind those fronts regularly penetrating further into the continent.
Not necessarily more rain per event either as the tropical infeed of water vapour from the NW down along the fronts is the essential requirement here for big frontal rain events.

Big Pete, I have just posted on the Climate thread and the "Science in AGW" my thinking at the moment but please don't in any way take any of what I have posted as a given.
I'm just a 73 old uneducated wheat cocky now retired and I knows nuthin!

On my climate post on the weak solar cycle 24, even the guys who get paid for this are floundering quite a bit at the moment as to what "may", repeat "may' happen to the climate and subsequently to the polar vortex, SAM and anything else climate at the moment with this very low activity solar cycle 24 under way, all is still way up in the air but similar former grand minimums such as the Sporer, Dalton and Maunder minimums were bloody cold.

Not that they will admit it that they are scrabbling around for a firm footing on the science at the moment as most have very precious egos to protect as the former head of Sydney Uni recently put it.

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#989486 - 14/05/2011 15:17 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
Vinnie Offline
Meteorological Motor Mouth

Registered: 17/05/2006
Posts: 6821
Loc: Mulambin , Yeppoon Central Qld
The influence of the Indian Ocean Dipole (IOD) on Australian rainfall is currently neutral. A weakly positive IOD event has been forecast to develop during winter. In the past, positive IOD events have been associated with drier conditions over parts of Australia, particularly in the south east, during the winter and spring seasons.

--

What does a neutal influence of IOD mean for SW WA ?

And isn't a positive IOD bad ? Meaning less rain for us ?
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#989501 - 14/05/2011 18:18 Re: The Southern Annular Mode [ SAM ] [Re: Vinnie]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
Vinny just go to the BOM's IOD pages under "climate" and you will find the maps of rainfall and etc and combinations with the El Nino / La Nina in some cases as well.

Australian rainfall patterns during positive Indian Ocean Dipole
years


Australian rainfall patterns during negative Indian Ocean Dipole
years


About the Indian Ocean Dipole

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#989506 - 14/05/2011 18:48 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
Edit; sorry didn't answer your question re neutral or more correctly, no IOD.

I haven't caught up with any material on the IOD or non IOD year's effect on the SW of WA.
But i would hazard a guess that the SW is not affected very much at all by the IOD. Some time ago the CSIRO / BOM climate researchers claimed that the SW of WA was affected by the Pacific's ENSO system phases, the EN and LN but I haven't seen that claim repeated in my contacts with them.
What has happened here is that for some 14 or 15 years a winter high pressure centre sat over south eastern Australia so when those southern winter fronts came roaring through across the Bight, they hit the high pressure to the south of SA and then were diverted and turned to a south east track and never made it into the SE / Vic areas with any real strength or much in the way of precipitation.
So we were dry, dry and drought with a whole series of failed or bad and poor seasons and constant crop failures or poor crops for some 14 years since the mid 1990's here in western Vic and right across southern NSW.
The BOM got a project going about 3 or 4 years ago to try and figure out why that high was fixed and stationary over south eastern Australia for so long.

Now I am inclined to think that the high has migrated westwards as we have been starting to get some decent rain events at last and has settled down across the Western Australian wheat belt areas which is the southern half / third of WA.
The summer trough down along the inland western areas of WA didn't seem to get going and I think it was out to sea in the IO for most of the season which would give WA almost constant hot very dry desert air easterlies as they flowed into the quasi stationary off shore trough.
If a winter high, maybe ours from all those long 14 years has moved westwards or even eastwards and another has moved in to taken it's place in WA and settled in then it will take something unusual to break it up.
The BOM and CSIRO climate guys have some solid research ahead of them to come up with the answers and i can't for sure as a layman.
Sorry, but until you get a real shift in the systems then you may be stuck with a dry period like we had so go back through your rainfall history and check for any long dry / drought previous spells over the last century or so and that will give you some indication on the longest period you may expect to see this run for as some of those events are close to repeats.

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#989509 - 14/05/2011 19:06 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
Sorry: Clarification; Those high pressure areas I was posting about in eastern Australia and now possibly in WA should have been described as very large areas of consistently higher pressure than normal not "high pressure" [ cells ] per se.

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#989524 - 14/05/2011 20:57 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
S .O. Offline
Weatherzone Addict

Registered: 31/01/2011
Posts: 1540
Loc: Southern Victoria
ROM , Vinny

Isn't the IOD Forecast at this time of the Year taken with a pinch of salt ?( Uncertainty ) till atleast June but more so July .

I would say that when the Sth Eastern states DON"T receive those NW cloudbands that bypass the west coast overland which are usually seen in Strong Negative IOD events , and IF we head into a Positive IOD that these Tropical/ Subtropical water vapour/moisture return paths may shift out further west . Hence via more chance of Fronts extending up into Central Indian Ocean , meet up with troughs and then maybe drag some of this moisture down in Pre frontal cloud bands . Delivering more NW originated rainfalls for the West coast . This however would only start to occur near the peak of the SAM/ AAO's influence and on into Spring . So Vinny I wouldn't give up on the YEAR yet . ( But early season is probably too late for your farmers. )
And yes as you've shown elsewhere, 2008 ( ENSO ? ) was a standout as average or just above in the rainfall stakes . Rom's advise on checking back through to see any cycles is paramount to getting to know what to expect regionally . Remember to also see what happens elsewhere in the country leading up to those better years in WA . ( ie : what was 74, 75, 76 like over that way !)
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#989531 - 14/05/2011 21:30 Re: The Southern Annular Mode [ SAM ] [Re: S .O.]
Big_Pete Offline
Weatherzone Addict

Registered: 19/12/2004
Posts: 1955
Loc: Perth
If I remember rightly 2005 was a good winter rainfall wise over here. What was the situation over eastern states at that time?

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#989539 - 14/05/2011 21:52 Re: The Southern Annular Mode [ SAM ] [Re: Big_Pete]
S .O. Offline
Weatherzone Addict

Registered: 31/01/2011
Posts: 1540
Loc: Southern Victoria
hehehehe ,

I don't know that much about 2005 over east first hand, 'cause i was over therein WA 2004-2007 . !!!

I remember the May as being particularly active as my wetsuit never had a chance to dry , and we had the island ( Rottnest ) to ourselves a the Ferries were perpetually cancelled .
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#989544 - 14/05/2011 22:20 Re: The Southern Annular Mode [ SAM ] [Re: Big_Pete]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
Pete, took me about 2 minutes on the BOM site to find the rainfall figures for Horsham in western Vic in 2005

Just use "Climate data on Line" under BOM's "Climate" section on their home page.

Horsham A/D where the station is located [ est 1998 ] had 391 mms for the year 2005.

Long term average since 1891 at Longerenong BOM Station, one of the oldest recording stations around, about 10 kms east of the Horsham station is 413 mm average annual rainfall.

So year 2005 had just 22 mms under it's average rainfall and that was one of the better years over the last 14 years up to 2009.

What is not known about the location of Horsham by most is that it actually sits almost on the interface between the maritime air mass from the Southern ocean a couple of hundred kilometres to the south and the much drier continental air mass to the immediate north of the city.
We fly that NW / SE line of interface instability quite often in the gliders.
South and west of Horsham can be and often is wet, very wet but north of Horsham we will be very dry or drought at the same time as the rainfall drops off that fast as we move north of Horsham and that Maritime / Continental air mass interface line.

Just another quirk of weather and climate that unless you are a local and a weather nut and maybe a glider pilot and farmer you just won't realise that such differences can occur over such short distances. And do so across country that is so flat that one WA visitor claimed if you tipped over your beer it wouldn't stop running for 40 kms.

Just north of Horsham the rainfall drops off at about 25 mms every 25 kms until up past Warracknabeal to the north the rainfall totals are about 350 mms average and on down to 325mms further north.

West of Mildura and some 280 kms north of Horsham and north of the Sunset Desert country in the Millewa, wheat and barley are grown in a 250 mm mostly winter rainfall zone, one of the driest spots in the world where crops can be grown with regularity.

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#989553 - 14/05/2011 22:53 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
S .O. Offline
Weatherzone Addict

Registered: 31/01/2011
Posts: 1540
Loc: Southern Victoria
Being in a place really gives you an appreciation from where those rainfalls originate from ( direction ) or type of system .
Not that I've done it , because I'm more interested in the weather of where I'm usually not . I think the best thing is a weather diary , I know alot of older surfers have done well with these in the days of pre computers , and i believe pilots may or may not do this type of thing .
So sometimes Data is good but usually first hand knowledge is better . Just like the acummulated knowledge that ROM talks of . Checking the Data is Good when you have the time to check neighbouring sites and see particular anomlaies which arise from the direction and nature of any event , or season . But gee it gets adnauseum .

So like Pete is angling at , questions to the right people . Not only helps those seeking info , can also help the other end provide their source of Info in a more refined light and inturn helps the responders own knowledge . As true knowledeg is only accumulated not once it is understood , but once it can be clearly conveyed . Of which the latter , I'm obviously still learning . lol
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#989632 - 15/05/2011 13:00 Re: The Southern Annular Mode [ SAM ] [Re: S .O.]
Big_Pete Offline
Weatherzone Addict

Registered: 19/12/2004
Posts: 1955
Loc: Perth
Yeah I'm planning to be a meteorologist when I leave school and I'm trying to learn as much about all the complex stuff about meteorology like influences on the climate and local topography influencing things like severe thunderstorms, ect.

I went to the climate prediction centre and tried to find info on the ENSO cycle and shows this image.

Anyone know what is means and how it is affecting the weather?

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#989636 - 15/05/2011 13:44 Re: The Southern Annular Mode [ SAM ] [Re: Big_Pete]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7770
Loc: Adelaide Hills
Originally Posted By: Big_Pete
I went to the climate prediction centre and tried to find info on the ENSO cycle and shows this image.

Anyone know what is means and how it is affecting the weather?

Two things seem fairly apparent at a glance:

First, there is a pressure anomaly north of 20 degrees north in the Pacific Ocean which is the opposite in each image, as is a pressure anomaly zonally (by longitude) at 20 degrees north. This I would associate with phases of the Pacific Decadal Oscillation.

http://jisao.washington.edu/pdo/

Second, it is clear there is another pressure anomaly zonally across the Indian Ocean into Southern WA, central and south SA. This I would associate with either the IOD or, I suspect more likely, the 3-wave pattern of the Southern Annular Mode.


Edited by -Cosmic- (naz) (15/05/2011 13:45)

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#989956 - 17/05/2011 11:04 Re: The Southern Annular Mode [ SAM ] [Re: Seina]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
WUWT now has an "Atmospheric Oscillations Page" with all the various global oscillation indexes and etc available.
Saves going to a number of sites for the latest indexes and trends and includes a very extensive reference source guide.

http://wp.me/P7y4l-amQ

Other WUWT reference pages can be found here; http://wattsupwiththat.com/reference-pages/

Listed;
Atmosphere Page
ENSO (El Nino/La Nina Southern Oscillation) Page
Geomagnetism Page
Global Climate History
Ocean Page
Sea Ice Page
Solar Page
US Climatic History Reference Page
US Weather History

[ WZ might like to include this reference list in it's weather site and / or on the Forum.]


Edited by ROM (17/05/2011 11:14)

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#991756 - 27/05/2011 13:15 Re: The Southern Annular Mode [ SAM ] [Re: ROM]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7770
Loc: Adelaide Hills
Originally Posted By: ROM
The rainfall pattern follows the SAM index but has a lag of about a week to ten days behind the SAM index and that is exactly what seems to be happening with the current SAM index and the potential forecast rain for SE Australia around next week end.

Over the period of the SAM index in the above link, when the SAM index is neutral or positive it stayed dry around SE Australia or dry at least in west Vic.
When the SAM index dipped to a significant negative number, we got rain about a week or so later.

This is related to the SAM, but indirectly. You comment “we got rain about a week or so later” arouse my suspicions. I am interested in teleconnections between SSTs and the SAM. Do you know of a link to sub-SST time series data extending back to 1979 on a monthly timescale for the region south of Australia (the Bight)? I am aware of the Blue link Database, I just need something rather lengthy to do more analysis. I’m just giving this a try smile .

Thanks for your feedback in advance.

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#991803 - 27/05/2011 19:04 Re: The Southern Annular Mode [ SAM ] [Re: Seina]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
Cosmic, I've done a few minutes digging on the net and have come up with the IRI's Levitus data base.

http://iridl.ldeo.columbia.edu/SOURCES/.LEVITUS94/

Now there is no way I have explored this yet and to be frank, most of it is beyond my ability to fully understand.
Just poking around in that data base and there is one heck of a lot of data to be mined there.
I did see some data bases going back to 1971 so it is possible that there is data from the Bight area in there some where but it is likely to be only of a limited time frame as it would have been collected from research vessels.

The first sat SST's for the area were done sometime prior to 1981 ; http://www.marine.csiro.au/~griffin/articles/MF03115.pdf

Quite a bit on marine parks with some SST's included ; http://www.environment.gov.au/coasts/mpa/publications/pubs/remote-sensing-assessment-figures1-49.pdf

Southwest Australian Shelf with SST graphs from Hadley back to 1957.; http://www.lme.noaa.gov/LMEWeb/LME_Report/lme_43.pdf

Don't know if these will help but I hope so.
Cheers.

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