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> From: Toshio Yamagata <yamagata@eps.s.u-tokyo.ac.jp>
> Subject: pIOD is coming back?
> Date: Sun, 24 Jun 2007 07:47:11 +0900
>
> Dear Mina-sama:
> It appears that IOD is coming back again in the IO just like the very rare
> case in 1967. It might be too early to say this but our CGCM prediction
> seems to be correct. Please visit the Indian Ocean observations at
> http://www.jamstec.go.jp/frsgc/research/d1/iod/ updated by Surya Rao-san. I
> am afraid that La Nina plus pIOD may cause very hot summer in East Asia
> with serious drought associated with localized heavy guerrilla rains as in 1967.
> Best regards, Yamagata
>

Dear Sensei, and Colleagues,

The latest observations (see attached PPT) did show some evidence for
the possible occurrence of positive IOD this year. Japan had less
rainfall and delayed onset of Meiyu/Baiyu season in June.

Best regards,
Jing-Jia

SST.wind.SSH.obs.jun07.ppt

Dear Luo-san and colleagues,

Just for your information.
TRITON temperature at 1.5S, 90E indicates subsurface cold
anomalies at the thermocline depth and deeper layer after
mid-May, which is quite similar to the conditions in 2006.
(This also suggests very weak spring Wyrtki jet in May this year.)
Our post-doc Horii-san kindly made us the attached figure.

Best regards,
Yukio

TRITON.pdf

Dear Yukio and Horii-san,

Thank you for keeping us up to date. 2006 and 2007 are turning out to be
most interesting years. I hope the SINTEX-F prediction is wrong because it
might cut down the rainfall Australia normally receives from La Nina. But
then we really don't know the rainfall pattern for La Nina/IOD+!!

And while I have your attention, would all please note my new email address
Gary.Meyers@imos.org.au and change your contact list?--gary

PLEASE NOTE MY NEW AFFILIATION, AND COORDINATES
Prof Gary Meyers, Director
Integrated Marine Observing System
University of Tasmania
Private Bag 110, Hobart, Tas, 7001
Room 265, Centenary Building, Grosvenor Crescent, Sandy Bay, Tas, 7005
Phone 03 6226 2767, Facsimile 03 6226 2107

 

Dear Masumoto-san: Thank you for the very interesting in situ
subsurface data from the TRITON buoy. The eastern IO continues to be
cold since last pIOD except for the very short period of the arrival
of the spring Yoshida-Wyrtki jet. The current situation is very
similar to pIOD year 1967 (assocated with La Nina) after pIOD in
1966 (associated with weak El Nino; leave the precise definition
alone). I think we had better go ahead about cautioning regional
societies about possible floods/ droughts/hot conditions.
Best regards, Toshio Yamagata

 

Dear Toshio and all,

I would caution against rushing to a public announcement. Seasonal
predictions can be very upsetting to the publice who live in areas at risk.
At a minimum I think any public announcement should be based on a
multi-model summary. I note several groups that routinely run a seasonal
forecast are on this mailing list. So I would like to know if the other
groups can or will make their predictions for the Indian Ocean available.
Perhaps these could be assembled and if appropriate the announcement made on
the basis of a multimodel summary.--gary

Dear Colleagues

Perhaps it is a good idea to check forecasts from several models as
suggested by Gary. But I am not sure if that will help to improve the
confidence in model predictions. I know that MME predictions do a better
job than a single model predictions. In a situation where 9 out of 10
models are giving wrong predictions, we have no way to improve a
particular model forecast.

Last year, because of the debate early on during the development of IOD,
we delayed the press release until August. But probably because of the
delay in the announcement the information could not be utilized by
people who were most affected by the 2006 IOD. More than a million
people in East Africa suffered from floods and Australian farmers had to
manage with severe short-supply of water and fodder. Some of the farmers
who kept calling us almost on daily basis told us that they could have
been benefited had the information about the IOD was passed on to them
based on our model predictions.

Interestingly, several models predicted a negative IOD in 2006 until the
late stage of IOD formation. So, it is not clear how soon is too soon to
announce a model prediction. But I feel to save people from extreme
climate conditions, at least, we need to pass some cautionary notes to
the decision makers based on the models that shows consistently good
skill in seasonal climate predictions. Together with the monitoring
system, even a moderate prediction can be very beneficial to the
society.

Best regards
Swadhin Behera

Dear All,

Following the discussions initiated by Gary and Behera I wish to bring
it to your notice
that many CGCMs predict a pIOD this year. Please have a look at the
attached
figures.

Best regards,
Rao

Dear Swadhin,

Email is not a good way to have the discussion we need to have. All I'm
calling for is that we be deliberate in our judgement in this serious
matter. I think it is a decision to be made by the small group of experts
who generate forecasts of the Indian Ocean--gary

Dear Gary:

Thank you for your thoughtful comments and for raising a very important
issue. I understand your anxiety; it is quite reasonable particularly from
the viewpoint of weather bureaux that are responsible for outcomes of their
<forecast>.

Once we release the information of another pIOD in 2007, suicide rate of
Australian farmers, for example, might increase at a significant level. If
our <prediction> turns out to be wrong, we might be accused of this. If
the Earth climate follows our prediction, on the other hand, no release of
such future information will lead to loss of many lives, particularly in
developing countries, as Swadhin mentioned. No one except for our frontier
scientist conscience will blame us in the latter case.

Just like the global warming issue, we need to discuss whether a
<precautional approach> of frontier scientists (rather than operational
agencies' official ones) in the seasonal <prediction> is beneficial to the
society or not. We need to evaluate this scientifically. Personally I
think it is useful as a whole even at the present level. The difference
between the evolving seasonal <prediction> in the tropics and the weather
<forecast> is becoming only quantitative because of the steady progress
(even if it is very slow) of our <prediction> skill. (Please remember the
weather <forecast> in the 1960s right after the innovation of Neumann and
Charney.) The situation seems to be even much better compared to the
global warming <projection> that has qualitative difference from the
seasonal <prediction> as well as the weather <forecast>.

Best wishes, Toshio

Hi Rao, I think you picked up the forecast for east Indian Ocean SST from POAMA. The attached figure is the prediction for the dipole index from POAMA
POAMA is going for a negative IO dipole. The other figure is a spaghetti plot of the contour of the max SST anomaly from each member that verifies in October for forecasts that were initialized this month. POAMA is obviously still going for La Niña, and warm SST in east IO. Given the weak negative SST anomalies in the east IO as of this week, and the fact that some of the members from POAMA start out going cold in the east IO, it will be interesting to see how things evolve.

 

Harry
Indian_dmi[1].gif

hr_spg_4[1].gif

Yamagata-san,

I think that your comment, and those of Swadhin and Gary raise an
important set of issues. It is important to communicate, along with the
forecast, a measure of uncertainty. Many groups within the larger
"forecast user community" are well set up to deal with uncertainty in a
forecast. Even people not formally trained in statistics, and without
cost-benefit models for their industry, will often have an intuitive
appreciation of probabilistic forecasts - I believe that gambling is one
of the most universal components of human societies.

I do not know what the other forecast systems - beyond Frontier and
POAMA - are predicting for this coming season. Using the spread between
the forecasts may be a decent estimate of uncertainty, right now that
gives a 50/50 forecast - but that's not a good estimate, since with two
elements it's either 100% or 50/50. What do the other centers say?

Another way would be to have probabilities of "false positives" and
"false negatives" for both forecast systems, and use those to assess the
combined forecast. Does anyone have those probabilities for the POAMA
and Frontier systems?

It is my opinion that these forecasts can be usefully communicated to
society, but it is essential that the uncertainty inherent in them is
communicated as well. The probabilistic forecasts will allow for the
forecasts to have some potential utility, as well as help minimize some
of the potential for the negative unintended consequences.

Given how unusual it is for IODs to follow eachother, and how unusual it
is for IODs to occur with La Niña events (one of which is limping
along), I'm feeling cautious about the forecasts. But anyone who
listened to my forecast last year (I said no IOD) knows better than to
pay attention to what I say on this.

Regardless, it's very exciting to see the forecast systems working and
the in situ data being used (nice plots, Yukio). Such a change in a few
years.

Gabe

 

Dear Toshio,

I remember reading the Neumann and Charney paper, some years ago, probably
about 10 years after it was first published. I still marvel at the progress
numerical weather prediction has made, and I think seasonal climate
prediction is on a similar long term track. The question is how do we
interact with the public now, in this early stage? We need to take into
account both the best interest of the public and the advancement of our
science. Along with R&D on the coupled systems there has to be research on
how to best make societal use of the Indian Ocean predictions.

If you make an announcement now, based on SINTEX-F, it will be a
result/forecast that is quite simple and clear. It will be interesting and
probably it will be picked up by the media. Also, it probably will be
sensationalized. We have to ask ourselves, what can people in the affected
areas do with such information? Maybe they can do something but it will have
to be tentative. If strong action is taken, there is a risk that the
forecast is wrong and that also causes damage.

If a group of operational and/or experimental forecasters put together a
statement based on multi-model information, it will represent the state of
our science better. It will have to be scientific in nature and may not be
so interesting or easy to read for the public. It may or may not be picked
up by the media.

As I see it we have a dilemma, as you point out. It is even a double edged
dilemma--properly informing the public and properly representing our
science.

I still would like to see the small group of seasonal forecasters--perhaps
only the ones running state of the art experimental systems--put together a
consensus statement.

Best regards, Gary

 

Dear Gary:

Thank you for your thoughtful comments and for raising a very important
issue. I understand your anxiety; it is quite reasonable particularly from
the viewpoint of weather bureaux that are responsible for outcomes of their
<forecast>.

Once we release the information of another pIOD in 2007, suicide rate of
Australian farmers, for example, might increase at a significant level. If
our <prediction> turns out to be wrong, we might be accused of this. If the
Earth climate follows our prediction, on the other hand, no release of such
future information will lead to loss of many lives, particularly in
developing countries, as Swadhin mentioned. No one except for our frontier
scientist conscience will blame us in the latter case.

Just like the global warming issue, we need to discuss whether a
<precautional approach> of frontier scientists (rather than operational
agencies' official ones) in the seasonal <prediction> is beneficial to the
society or not. We need to evaluate this scientifically. Personally I
think it is useful as a whole even at the present level. The difference
between the evolving seasonal <prediction> in the tropics and the weather
<forecast> is becoming only quantitative because of the steady progress
(even if it is very slow) of our <prediction> skill. (Please remember the
weather <forecast> in the 1960s right after the innovation of Neumann and
Charney.) The situation seems to be even much better compared to the global
warming <projection> that has qualitative difference from the seasonal
<prediction> as well as the weather <forecast>.

Best wishes, Toshio

Gary, I was thinking about the official seasonal forecast issued from BoM (which is currently based entirely on empirical relationships). They don't even factor in the IOD. They assess the likely state of El Niño, and the likely state of the subtropical Indian ocean (the so called Nicholls dipole), which was shown to have a relationship with Australian winter rainfall in an older Nicholls paper (which I think is now regarded as a bit of a red herring as far as predictive capability is concerned). The importance and predictability of the IOD has not percolated up (or down) to those who issue the forecast. I guess that's the fault of the researchers (like me) in BMRC.

For those interested, I include a link to the official BoM seasonal forecast issued last July 2006, when we knew we going to have a pIOD. As you can see from reading the justification of the BoM forecast,

http://www.bom.gov.au/announcements/media_releases/climate/ahead/20060725R.shtml

the warm loading onto the subtropical IO was an important factor. This link shows what this SST pattern is in the IO http://cas.bom.gov.au/misc.dir/atlas.dir/index.html , which you can see has nothing to do with an IOD. So, in the official BoM forecasts, there is no mention of the IOD. Of course as it turned out last year, the official forecast for the SE of Australia wasn't too good: we had a pIOD and record drought.

 

 

Ideally, in the near future the Bureau will switch their official seasonal forecast to the direct output from the dynamical ensemble system (single model or multi-model), for which the hindcast skill is well documented. In this case, we won't selectively call out a dipole event or El Niño event, rather, we will directly provide the regional climate predictions (e.g. pdf of eastern Australian temperature and rainfall) that result from prediction of the entire coupled system.

Harry