[jules' pics] 8/31/2010 05:28:00 AM

foreign signs, originally uploaded by julesberry2001.

Last weekend another visit to far off lands. This time to visit James' auld mither an faither.

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Posted By jules to jules' pics at 8/31/2010 05:28:00 AM

[jules' pics] 8/27/2010 01:49:00 AM

Pakistan v England at Lords, originally uploaded by julesberry2001.

Maximum Entropy day was yesterday. It is fortunate then that the least important part of making a pilgrimage to Lourdes is the actual cricket.

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Posted By jules to jules' pics at 8/27/2010 01:49:00 AM

[jules' pics] 8/25/2010 03:22:00 AM

tipping punt, originally uploaded by julesberry2001.

More about the program; this morning is all about tipping punts. Sorry..I mean Timmy points. Timmy himself gave a fun overview talk about them on Monday, but now its gone all nitty gritty. Still - must soldier on - the workshop dinner is tonight.

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Posted By jules to jules' pics at 8/25/2010 03:22:00 AM

jules pics - robin

moultiing robin, originally uploaded by julesberry2001.

All getting very Britishy now...we don't get these back home. I suppose this might be a young robin coming into adult plumage, since it has a brown speckled head... probably blog readers know better and I looked forward to being corrected.

Having said that about the Britishness, this was shot in Kent, which is a bit of a rum place. While it seems to be about the only place in the UK which actually enjoys the kind of summers assumed in English children's books (that is the kind that is full of ripe forest fruits and golden meadows, and during which one may venture outdoors without a big jumper and a raincoat), Kent also has fleets of parakeets and big snakes!

Mathematical and Statistical Approaches to Climate Modelling and Prediction

A commenter worked out where we were and asked about the programme. I haven't had anything to say so far because although we have now been here for more than a week, it was pretty quiet at first, and we were mostly spending our time on some fairly routine work we had brought with us. This week, however, is the first workshop, and it is rather busier.

My first thoughts on reading the blurb (back when we were first invited last year) was that it seemed to have a slightly split personality to me, with two components that have only tenuous links. The second component is the one that directly interests me, as it concerns the development and use of probabilistic methods for climate prediction (which in context and based on attendees primarily means the O(100y) problem). The first component, however, which is the main topic of this opening workshop, is the use of stochastic sub-grid physics parameterisations, which can modify (and improve) the behaviour of weather and climate models in various ways. Tim Palmer has been pushing this for some time and it's clear that he is on to something as far as improving short and medium term weather forecasting. However, he presented this as a grand plan for replacing the ensemble of CMIP models, but it seems immediately obvious to me that the stochastic physics approach does not begin to address the sort of uncertainties in the equilibrium climate state and response that dominate the climate prediction problem on the century time scale. It's just a better parameterisation, but still in principle a single parameterisation which will give rise to a single climate and single climate sensitivity etc, as the uncertainty the stochastic part introduces will generally be negligible over long time scales (coincidentally, I wrote a short and trivial paper on this way back in the mists of time). In order to generate climatologically different models, we would need different probabilistic schemes, not just a different sequence of samples from the same scheme. I asked him about this after his talk and was not convinced by his response.

There was also a talk on maximum entropy, which confirmed my suspicion that I should not attempt to learn anything about maximum entropy. I consider that an hour well spent!

More on the multi-model mean

Well the mystery surrounding the origins of this equation has been at least partially resolved. It is clearly presented in Stephenson and Doblas-Reyes "Statistical methods for interpreting Monte Carlo ensemble forecasts" Tellus 2000 (as the first author pointed out to me last week), who attribute the result to Epstein 1969 and Leith 1974. The attribution seems a little unclear to me, as these earlier papers both present a large number of equations relating to the evolution of forecast ensembles of specific systems, whereas this identity is fully general irrespective of the ensemble generation. However it is not in doubt that it is well known by lots of people and dates to the origins of ensemble methods in weather prediction, even though it has perhaps been subsequently forgotten by some (and apparently never known in climate science, or indeed numerous other fields).

[jules' pics] 8/23/2010 05:50:00 AM

Royal Albert Hall, originally uploaded by julesberry2001.

Anonymous suggests we blog the program. So here it is.

Prom 50, 22nd August 2010:
Mozart: The Magic Flute - Overture
Bartók: Piano Concerto No.3
Bartók: Cantata profana
Haydn: Symphony No.102 in B flat major

Kamakura is an hour on the train from Tokyo, Cambridge the same from London, and just like at home, the train whizzed us effortless home from the night-time fun in the big city - well, not quite as comfortably, but it was on time.

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Posted By jules to jules' pics at 8/23/2010 05:50:00 AM

[jules' pics] 8/20/2010 04:27:00 AM

Centre for Mathematical Science, Cambridge, originally uploaded by julesberry2001.

A brief break between rain showers in Cambridge.

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Posted By jules to jules' pics at 8/20/2010 04:27:00 AM

[jules' pics] 8/19/2010 02:31:00 AM

political correctness gone mad, originally uploaded by julesberry2001.

jules tries to blend in... hopefully redressing the Daily Mail imbalance.

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Posted By jules to jules' pics at 8/19/2010 02:31:00 AM

[jules' pics] 8/18/2010 01:33:00 AM

James in a hat, originally uploaded by julesberry2001.

Nick Barnes is to be congratulated for working out that we are in Cambridge.

Now that's out of the way perhaps I can post some nice photos of Cambers. Here's a bauble wot some old mate of my father-in-law recently stuck up outside Corpus Christi College, which, coincidentally is also where I did my PhD. The bauble is part of a clock which has a beetle on the top of if that is almost as large as some of the ones we get in Japan, but the glass in front of the clock is very reflective so multiple reflections seemed the way to go photographically. That's the front of King's College that you can see behind James.

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Posted By jules to jules' pics at 8/18/2010 01:33:00 AM