RE: [austpacwx] David Jones/Blair... is this odd? [SEC=UNCLASSIFIED]

[David Jones]

There are two explanations for this (which are intertwined). The first is this climate model includes greenhouse gases in its seasonal forecasts, and every year that goes by this introduces a warming of (about) 0.015C. Over the climatology period of this model it now means that regardless of the status of El Nino/La Nina you have an expectation that anomalies will be significantly positive.

The second is the rapidly intensifying El Nino with record to near record warm ocean temperatures across almost the whole tropical and subtropical oceans. Of course, part of the reason the oceans are hot is El Nino and partly because of the enhanced greenhouse effect. Given the massive heat capacity of the oceans this heat will not go away quickly and will provide a significant "heat source" for the overlying atmosphere for months to come.

The next year is not going to be pretty. A significant El Nino, plus a return to more normal solar activity (following a very striking solar minimum), and the enhanced greenhouse effect will see many global temperature records challenged if not broken.

BTW most statistical climate models do not include greenhouse gas increases (there are historical reasons for this).

David

From: Ken Kato [kka...@hotmail.com]
Sent: Wednesday, 4 November 2009 1:32 AM
To: Austpacwx
Subject: [austpacwx] David Jones/Blair... is this odd?

Hi David and/or Blair,

I noticed something that really caught my eye before. EC's forecast for NDJ has very high probabilities of warm 2m temp anomalies over almost all the tropics/subtropics of the planet. The example I looked at is attached. So I decided to check some more and found this was also reflected in the upper 1/3rd of the prob distribution as well as the highest 20% of the distribution (huge expanse of warm temps). This continues out to all lead times and seems to even spread with time.

The multimodel Eurosip shows the same thing. The expanse of these anomalies also shows up well on IRI's multimodel forecast for NDJ (attached). UK, JMA & CFS (which was only initialised 2 days ago) seem to be less dramatic about the whole thing. Does the widespread nature of these anomalies seem a bit odd to you?

Ken.

--

You received this message because you are subscribed to the Google Groups "austpacwx" group.
To post to this group, send email to aust...@googlegroups.com.
To unsubscribe from this group, send email to austpacwx+...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/austpacwx?hl=en.

[Ken Kato]

These are the same 2 things that passed through my mind when I saw the outputs  i.e. greenhouse effect lifting most of the forecast temps above the model's base climo mean, and the warm waters both in and outside the Nino regions.... although wasn't sure about either, especially the latter  i.e. direct result of the unusual SST patterns or the unusual El Nino perturbing the model's initial conditions and somehow making it produce equally unusual warming. Will be interesting to see if there'll be a noticeable effect on future anomalies when the model's base climo period is updated to extend beyond 2000. In any case, I'm sure this is the first time I've seen progged warming on such a big scale for these particular models.

> The next year is not going to be pretty. A significant El Nino, plus a return to more normal solar activity (following a very striking solar minimum), and the enhanced greenhouse effect will see many global temperature records challenged if not broken.

I noticed solar activity in the past couple of months seems to have just started to pick up now. Is there usually around a 1 to 2yr lag before we start seeing a response in global temps response to the 11yr solar cycle from the oceans' thermal inertia... or do land temps start rising straight away?

> BTW most statistical climate models do not include greenhouse gas increases (there are historical reasons for this).
 

I think it's interesting that the IRI forecasts still show the big expanse of warm anomalies despite the use of both statistical and dynamical models with a heavy weighting towards CFS (which doesn't even seem to be as dramatic with the warming)... although I'm guessing the warm contributions from other dynamic models are biasing it's forecast towards the warm anomalies.
 
Ken.

[Blair Trewin]

The 1997-98 El Nino saw a particularly striking temperature signal in many tropical areas, although November-January is a little early for this. A couple of years back I was involved in a study of extreme high temperatures in south-east Asia and 1998 (especially March and April) dominated to a huge extent in many locations.

 

Blair

---

From: Ken Kato [mailto:kka...@hotmail.com]
Sent: Wednesday, 4 November 2009 10:31 AM
To: Austpacwx
Subject: RE: [austpacwx] David Jones/Blair... is this odd? [SEC=UNCLASSIFIED]

[Clyve Herbert]

Hi all.

The present set-up of 'warm anomalies across the Pacific was not part of the winter spring outlook issued in May or there-about. The models more or less failed to predict the unusual 'general warming' of the Pacific and thus a long period of neutral El Nino activity  between May and Sept 09. I would be rather sceptical of this grand warming prediction and suspect a marked 'backing off' over the next several months. It would be crucial to site previous 'general warming' of the Pacific and apply to the models and study historical occurrences of a more uniform warming in the past especially when it comes to climate predicting...regards Clyve H

[Ken Kato]

Hi Clyve,
 
Most of the dynamic models I saw in the lead-up to winter did predict the warm SST anomalies in the western Pacific for winter-spring (and even warmer central/eastern Pacific leading to the unusual El Nino setup from late winter). See attached examples from UK and EC for this period.

When you say 'models', which ones were you referring to? I think this is where the distinction between dynamic and statistical models is important. My understanding is that statistical models take into account past correlations and behaviour of oceans, atmosphere, rainfall, etc. I believe the bureau's seasonal outlooks are based on such a statistical model of Indian/Pacific Ocean SST's, rain, etc. Both techniques have their pros and cons. Having said that, the overly optimistic side of me is hoping you're right (about the predicted warming not being as bad).
 
Ken. 

[David Jones]

All models which the Bureau uses (including the Bureau's POAMA model) for the prediction of El Nino are dynamically base. Statistical models have somewhat limited utility in this regard - essentially they are great and 1) predicting an El Nino/La Nina will continue (once established) through winter/spring and break-down the following summer (we know from history that this sequence almost always happens so you don't even need a model!). They are not much use for the more important issue of if an event will develop, or much good for predicting how strong an event might be.

This year the POAMA model provided stunning guidance about the development of El Nino. This allowed us to provide a very clear warning of a (likely) impending event.

DJ
________________________________________
From: Ken Kato [kka...@hotmail.com]
Sent: Wednesday, 4 November 2009 12:25 PM
To: Austpacwx
Subject: RE: [austpacwx] David Jones/Blair... is this odd? [SEC=UNCLASSIFIED]

[David Jones]

>or do land temps start rising straight away?

I think the answer is that it depends. Over the oceans there will tend to be a bigger lag than over land (owing to the greater thermal mass). That said the 11 solar cycle has only a tiny affect on global temperature (less the 0.1C). What is more important is the long term secular trend which has (by current estimates) cooled the planet by about 0.2C since 1950 (while at the same time the enhanced greenhouse effect has warmed the plant by something approaching 1C).

As an aside to be seeing near record high temperature in the early stages of an El Nino and at solar minimum is just simply astonishing.

DJ
________________________________________
From: Blair Trewin [B.Tr...@bom.gov.au]
Sent: Wednesday, 4 November 2009 10:43 AM
To: 'aust...@googlegroups.com'

[Ken Kato]

Thanks Blair. Just wondering if the 97/98 El Nino would be the closest
analogue to our current one in terms of characteristics like timing,
extent of effects, the mixed ocean-atmosphere signals til last month,
etc... or if there's a closer one?

Ken.

[Blair Trewin]

No, 1997-98 is not a good analogue - it was a much more classical event with the warm waters at this stage of the event focused on the eastern Pacific. Both 2006 and 2002 (as well as 1994) have SST patterns much closer to this year (in terms of the peak SST anomalies being in the central Pacific) than 1997 did.

Blair

-----Original Message-----
From: Ken Kato [mailto:kka...@hotmail.com]

--

You received this message because you are subscribed to the Google Groups "austpacwx" group.
To post to this group, send email to aust...@googlegroups.com.
To unsubscribe from this group, send email to austpacwx+...@googlegroups.com.

For more options, visit this group at http://groups.google.com/group/austpacwx?hl=.

[Ken Kato]

Hmm ok thanks, just curious about rainfall patterns with analogues to the current event although unsure whether or not there's too much variability/not enough analogues to be too useful. Come to think of it, I think I do recall the +ve SSTA's being concentrated in the eastern Pacific... and that classic tongue-like pattern being used as a textbook example of a classic El Nino in many El Nino discussions ever since.
 
Ken.

[Dr. Kelly D. Lash]

Interesting Blair to look at the cyclone tracks for those years .... Hmmm
and wonder whats up for this year?
Kelly
Cape Tribulation

[Marcus]

Quick question,

If you look at the Melbourne water website - in particular the inflow into
lakes since 1901, up until climate change, a severe el nino tended to appear
every 20 years ( from memory) now it is every 4 years.

Is it the case that frequency hasn't changed - just the serverity - or has
the shift in the atmosphere caused an increase in the occurance?