Tuesday, September 26, 2006
Friday, September 22, 2006
Can we believe in high climate sensitivity?
You've seen the film, now read the book :-)
(Oh, there's a paper size issue which cuts the header line off the pages of the pdf - that would have made it clear that this is submitted to GRL.)
I guess you could see this as a re-writing of the Comment on Frame et al as a stand-alone paper, but it's designed as more of a general comment about the whole field (at least, a large part of it) and is based largely on the presentation I gave earlier ths summer. However, since (as far as I can see) Frame and Allen are the only ones actually specifically advocating uniform priors, it's hard to avoid a direct rebuttal of ther claims. The increased character limit means that as well as explaining the problems with other approaches, we can present some new results.
The paper is basically complementary to our previous multiple constraints paper. That considered the effect of combining different observations, this one looks in more detail at the prior and we hope has put some final nails in the coffin of the uniform prior. We show that this approach doesn't work at all, and even if it did, the results would not actually be of any use. If we'd thought more carefully about it, perhaps we could have rolled both halves of the argument up into one paper at the outset, but it's too late for that now. The new results we show are based on the Forster and Gregory analysis. I know I said I wasn't intending to publish a paper based on this, but their analysis is particularly useful due to its independence from climate models and forcing estimates. It now seems to me that an upper 95% probability limit for climate sensitivity of about 4C is easy to justify.
I hope we manage to get some referees who do not have too much of an axe to grind in this debate. Any meaningful comment from readers here is of course also welcome.
We gave Nature the chance to reject it first, which didn't take long. Of course I knew it would be a waste of time sending it there, but I think it's only fair to give them the chance to make amends if I'm going to criticise them. Also, it's amusing to pick the bones out of their excuses. In this case, it was because there is apparently nothing new in our work - this from the same Nature that puffed up Hegerl et al as "the best guide yet" and refused to consider our comment pointing out some rather obvious limitations (effectively the same points that we discuss in our new manuscript). It seems quite clear to me that their editorial filter acts to obstruct rather than enable scientific progress.
(Oh, there's a paper size issue which cuts the header line off the pages of the pdf - that would have made it clear that this is submitted to GRL.)
I guess you could see this as a re-writing of the Comment on Frame et al as a stand-alone paper, but it's designed as more of a general comment about the whole field (at least, a large part of it) and is based largely on the presentation I gave earlier ths summer. However, since (as far as I can see) Frame and Allen are the only ones actually specifically advocating uniform priors, it's hard to avoid a direct rebuttal of ther claims. The increased character limit means that as well as explaining the problems with other approaches, we can present some new results.
The paper is basically complementary to our previous multiple constraints paper. That considered the effect of combining different observations, this one looks in more detail at the prior and we hope has put some final nails in the coffin of the uniform prior. We show that this approach doesn't work at all, and even if it did, the results would not actually be of any use. If we'd thought more carefully about it, perhaps we could have rolled both halves of the argument up into one paper at the outset, but it's too late for that now. The new results we show are based on the Forster and Gregory analysis. I know I said I wasn't intending to publish a paper based on this, but their analysis is particularly useful due to its independence from climate models and forcing estimates. It now seems to me that an upper 95% probability limit for climate sensitivity of about 4C is easy to justify.
I hope we manage to get some referees who do not have too much of an axe to grind in this debate. Any meaningful comment from readers here is of course also welcome.
We gave Nature the chance to reject it first, which didn't take long. Of course I knew it would be a waste of time sending it there, but I think it's only fair to give them the chance to make amends if I'm going to criticise them. Also, it's amusing to pick the bones out of their excuses. In this case, it was because there is apparently nothing new in our work - this from the same Nature that puffed up Hegerl et al as "the best guide yet" and refused to consider our comment pointing out some rather obvious limitations (effectively the same points that we discuss in our new manuscript). It seems quite clear to me that their editorial filter acts to obstruct rather than enable scientific progress.
Wednesday, September 20, 2006
Sumo
More "science" coming soon, I promise...but first...
Monday was a holiday - "Respect for the Aged Day", to be precise - and the weather was grotty, so we set off for Tokyo to see the sumo which is currently in town. There are 6 major competitions each year, three of which are in Tokyo, but we've not been to one before. Each meeting runs for 15 days, 9am-6pm each day (and you thought cricket was boring?) with several divisions of fighters starting with the lower grades and culminating with the top dogs. It's neither a knockout nor a round-robin, instead everyone fights 15 times in a division of about 40 fighters (I don't know if they have set methods for each day's draw or whether it is all decided in smoke-filled rooms, it is clearly not a Swiss tournament, as the current joint leaders seem to be being kept apart in anticipation of a last day decider).
We had checked on the web site that tickets seemed to be available on the door, but thought we'd better turn up early to make sure we got in. So by 9:30am we were sitting in a nearly-deserted hall watching what looked for the world like two fat men in nappies slapping each other around the head.
It was surprisingly good fun, actually. We watched some of the lower ranks for a bit to get a feel for how it was arranged, and then went out to do some shopping, returning for a bowl of chanko-nabe (a traditional food for sumo wrestlers, quite a tasty soup with meat and vegetables in but nothing special) and to see the better fighters - the ticket allows a single exit and re-entry.
The top division have a skirt-lifting parade before they start (watch it if you don't believe me!):
and then the current champion does a moonwalk across the dohyou (ditto!):
Before the start of each bout, the caller sings their names in a high-pitched voice (this is from an earlier bout, as later on the crowd noise drowned it out:
Then after some posturing and stamping, the bout begins. Some of them were over in seconds, some took rather longer (can you see Baruto's foot slip out while he's trying to throw Ama?):
After the final bout, one of the wrestlers comes in to show off his bow-wielding skills:
And then we all went home. All in all, an interesting day out, but not one I will be desperate to repeat too often!
Monday was a holiday - "Respect for the Aged Day", to be precise - and the weather was grotty, so we set off for Tokyo to see the sumo which is currently in town. There are 6 major competitions each year, three of which are in Tokyo, but we've not been to one before. Each meeting runs for 15 days, 9am-6pm each day (and you thought cricket was boring?) with several divisions of fighters starting with the lower grades and culminating with the top dogs. It's neither a knockout nor a round-robin, instead everyone fights 15 times in a division of about 40 fighters (I don't know if they have set methods for each day's draw or whether it is all decided in smoke-filled rooms, it is clearly not a Swiss tournament, as the current joint leaders seem to be being kept apart in anticipation of a last day decider).
We had checked on the web site that tickets seemed to be available on the door, but thought we'd better turn up early to make sure we got in. So by 9:30am we were sitting in a nearly-deserted hall watching what looked for the world like two fat men in nappies slapping each other around the head.
It was surprisingly good fun, actually. We watched some of the lower ranks for a bit to get a feel for how it was arranged, and then went out to do some shopping, returning for a bowl of chanko-nabe (a traditional food for sumo wrestlers, quite a tasty soup with meat and vegetables in but nothing special) and to see the better fighters - the ticket allows a single exit and re-entry.
The top division have a skirt-lifting parade before they start (watch it if you don't believe me!):
and then the current champion does a moonwalk across the dohyou (ditto!):
Before the start of each bout, the caller sings their names in a high-pitched voice (this is from an earlier bout, as later on the crowd noise drowned it out:
Then after some posturing and stamping, the bout begins. Some of them were over in seconds, some took rather longer (can you see Baruto's foot slip out while he's trying to throw Ama?):
After the final bout, one of the wrestlers comes in to show off his bow-wielding skills:
And then we all went home. All in all, an interesting day out, but not one I will be desperate to repeat too often!
Saturday, September 16, 2006
Disaster!
But only a pretend one, today at least.
Japan takes disaster preparation very seriously, with an annual "Disaster Prevention Day" when various drills and events take place. Before you laugh at the concept of preventing disaster such as earthquakes and typhoons, bear in mind that the magnitude of the consequences has as much to do with our preparation and response as with the natural event itself (eg consider Katrina/New Orleans).
Today wasn't actually disaster prevention day, but for some reason there was an event put on in Yokohama, I think deliberately targetting the foreign resident population many of who will struggle to comprehend the official Japanese language information. There were plenty of fluent dual-language speakers around, including the lady explaining this earthquake simulation. It's a reconstruction of the Great Kanto Earthquake of 1923, which killed about 140,000 (mostly in fires in the crowded streets)
It was a lot shakier to experience it than it looks on camera! Jules started off standing up but soon saw the error of her ways...several stories up in a tall building I imagine it could be very scary indeed.
There was also a smoke-filled room to negotiate (no photos from that!) and fire engines and extinguishers to play with. We actually bought a fire extinguisher a couple of weeks ago - yes, I know we should have done it ages ago, but we do have plenty of bottled water and food stocked up. Beyond this sort of obvious preparation, it's pretty much a matter of crossing our fingers.
Japan takes disaster preparation very seriously, with an annual "Disaster Prevention Day" when various drills and events take place. Before you laugh at the concept of preventing disaster such as earthquakes and typhoons, bear in mind that the magnitude of the consequences has as much to do with our preparation and response as with the natural event itself (eg consider Katrina/New Orleans).
Today wasn't actually disaster prevention day, but for some reason there was an event put on in Yokohama, I think deliberately targetting the foreign resident population many of who will struggle to comprehend the official Japanese language information. There were plenty of fluent dual-language speakers around, including the lady explaining this earthquake simulation. It's a reconstruction of the Great Kanto Earthquake of 1923, which killed about 140,000 (mostly in fires in the crowded streets)
It was a lot shakier to experience it than it looks on camera! Jules started off standing up but soon saw the error of her ways...several stories up in a tall building I imagine it could be very scary indeed.
There was also a smoke-filled room to negotiate (no photos from that!) and fire engines and extinguishers to play with. We actually bought a fire extinguisher a couple of weeks ago - yes, I know we should have done it ages ago, but we do have plenty of bottled water and food stocked up. Beyond this sort of obvious preparation, it's pretty much a matter of crossing our fingers.
Thursday, September 14, 2006
Tuesday, September 12, 2006
Blogapause
Not much going on here but the rain...at least it seems like summer has ended. I caught the first glimpse of higanbana in the verge near our house - this is the "equinox lily" whose appearance I've been looking forward to for about 3 months :-)
I did another practice JLPT test on Sunday and scraped over the magic 60% "pass" threshold this time - 241 points out of 400 to be precise, up 3% from the previous one a couple of weeks earlier. That was despite the handicap of doing the papers back-to-back in a noisy cafe with a caffeine overdose and plenty of distractions - loud Americans are harder to tune out than polite Japanese! I'm on the home stretch as far as learning the kanji and vocab goes, but still pretty awful at the listening comprehension (in fact my score even went down on this compared to how I'd done in the previous test). People who live in Japan and actually use Japanese to communicate seem to generally find this the easy part of the test, but it's only 25% of the overall score so not too crucial. There are still nearly 3 months left, so assuming I don't get lazy (and even if these tests are a bit on the easy side compared to the real thing) things seem to be on course. Perhaps it would be tempting fate to say that 70% is coming within range...
I did another practice JLPT test on Sunday and scraped over the magic 60% "pass" threshold this time - 241 points out of 400 to be precise, up 3% from the previous one a couple of weeks earlier. That was despite the handicap of doing the papers back-to-back in a noisy cafe with a caffeine overdose and plenty of distractions - loud Americans are harder to tune out than polite Japanese! I'm on the home stretch as far as learning the kanji and vocab goes, but still pretty awful at the listening comprehension (in fact my score even went down on this compared to how I'd done in the previous test). People who live in Japan and actually use Japanese to communicate seem to generally find this the easy part of the test, but it's only 25% of the overall score so not too crucial. There are still nearly 3 months left, so assuming I don't get lazy (and even if these tests are a bit on the easy side compared to the real thing) things seem to be on course. Perhaps it would be tempting fate to say that 70% is coming within range...
Wednesday, September 06, 2006
It's a boy...
...and any progress towards gender equality in Japan is thereby put back several decades. Here's the news, for anyone who cares.
Tuesday, September 05, 2006
A modern Difference Engine?
The Difference Engine was a mechanically-powered device which could perform a limited (but useful) set of calculations. As Wikipedia says: "This machine used the decimal number system and was powered by cranking a handle."
I've blogged briefly about my Zaurus before. It remains very useful, mostly for Japanese learning, email/web access and occasionally writing (typically blogs, more rarely scientific papers). However, it has a limited battery life of at most 8h, and much less when using the web. So I've investigated a number of options for recharging it when I go on longer trips away from civilisation - especially long mountain trips. (Yes, I know what you are thinking - why does he need to take that up the mountains? But the email doesn't work up there, it is only used for Japanese language and other amusements in the long afternoons spent idly at the huts.) Previously, I've often carried 4 AA NiMH cells which are an adequate substitute for the proper charger, together with a solar charger to top these up (the solar power is too much of a low trickle to directly power the unit reliably). But although this works, it's a bit of a hassle to set up and also annoyingly heavy given its relative "luxury" status for a walking holiday.
Recently I found a small hand-cranked dynamo, sold as an emergency mobile phone charger. It was only 5 quid, although the postage to Japan was as much again. And voila - the modern Difference engine - turn the handle to power the machine!
It claims an output of up to (limited to) 6V, and when applied to the load of the Zaurus (which has a 3.7V 1800mAh battery) it drops to around 4V or so. I haven't accurately checked the current, but I'd be surprised if I could get it above 500mA - perhaps 200mA is more realistic. It weighs about 70g, which is less than 3 AA cells, let alone the solar charger. I haven't actually used it in anger on a long trip yet, but it seems to work just fine in short tests. I guess it should also hook up with no problems to all sorts of USB-powered (=5V) gadgets with an appropriately-wired plug, so long as their current draw isn't too high. But follow my example at your own risk...
I've blogged briefly about my Zaurus before. It remains very useful, mostly for Japanese learning, email/web access and occasionally writing (typically blogs, more rarely scientific papers). However, it has a limited battery life of at most 8h, and much less when using the web. So I've investigated a number of options for recharging it when I go on longer trips away from civilisation - especially long mountain trips. (Yes, I know what you are thinking - why does he need to take that up the mountains? But the email doesn't work up there, it is only used for Japanese language and other amusements in the long afternoons spent idly at the huts.) Previously, I've often carried 4 AA NiMH cells which are an adequate substitute for the proper charger, together with a solar charger to top these up (the solar power is too much of a low trickle to directly power the unit reliably). But although this works, it's a bit of a hassle to set up and also annoyingly heavy given its relative "luxury" status for a walking holiday.
Recently I found a small hand-cranked dynamo, sold as an emergency mobile phone charger. It was only 5 quid, although the postage to Japan was as much again. And voila - the modern Difference engine - turn the handle to power the machine!
It claims an output of up to (limited to) 6V, and when applied to the load of the Zaurus (which has a 3.7V 1800mAh battery) it drops to around 4V or so. I haven't accurately checked the current, but I'd be surprised if I could get it above 500mA - perhaps 200mA is more realistic. It weighs about 70g, which is less than 3 AA cells, let alone the solar charger. I haven't actually used it in anger on a long trip yet, but it seems to work just fine in short tests. I guess it should also hook up with no problems to all sorts of USB-powered (=5V) gadgets with an appropriately-wired plug, so long as their current draw isn't too high. But follow my example at your own risk...
Monday, September 04, 2006
Super computer!
JAMSTEC's new supercomputer was switched on today, and there was a seminar introducing it. It certainly seems super to me! It's an SGI ALTIX 4700, with a total of 1280 dual-core processors. That linked press release talks about availability from late August, so having it up and running by the 4th September is very impressive indeed! Assuming I've done my sums right (not by any means a sure thing) it would slot in somewhere in the top 30 of the latest top500 list. It'll be further down the pecking order by the time the next list is drawn up, of course.
The only drawback I can think of is that it may prove rather more popular than the Compaq Alpha which it replaces (there must be someone's law: "all computers are the same speed", or perhaps: "jobs expand to fill the CPU available"). The Compaq Alpha was our favourite computer as it was good for highly parallel work (EnKF) but relatively lightly used, being a rather different architecture from the Earth Simulator which most code development here is aimed at. However, as well as the Altix there is also a new 24-processor SX8 which was just switched on today too, which may (I hope) be more popular for those who are more focussed on sharing code with the ES.
These two JAMSTEC computers are separately managed from the Earth Simulator, which I understand is also due for an upgrade in a few years (this is still officially in the planning stage, with funding not yet formally agreed).
I've grumbled a bit in the past about some of the drawbacks of working in Japan, so it's important also to give credit where it's due - the facilities here are in many ways second to none. The entire UK doesn't even have anything to compete with this Altix, let alone the ES. And this is all for climate science - I'm not even counting the 10 petaflop Simulator 2 which is likely to target other basic research, perhaps biological. Such a consistently high level of investment in basic research can't help but enhance Japan's image as a tempting destination for foreign scientists looking to expand their horizons...
The only drawback I can think of is that it may prove rather more popular than the Compaq Alpha which it replaces (there must be someone's law: "all computers are the same speed", or perhaps: "jobs expand to fill the CPU available"). The Compaq Alpha was our favourite computer as it was good for highly parallel work (EnKF) but relatively lightly used, being a rather different architecture from the Earth Simulator which most code development here is aimed at. However, as well as the Altix there is also a new 24-processor SX8 which was just switched on today too, which may (I hope) be more popular for those who are more focussed on sharing code with the ES.
These two JAMSTEC computers are separately managed from the Earth Simulator, which I understand is also due for an upgrade in a few years (this is still officially in the planning stage, with funding not yet formally agreed).
I've grumbled a bit in the past about some of the drawbacks of working in Japan, so it's important also to give credit where it's due - the facilities here are in many ways second to none. The entire UK doesn't even have anything to compete with this Altix, let alone the ES. And this is all for climate science - I'm not even counting the 10 petaflop Simulator 2 which is likely to target other basic research, perhaps biological. Such a consistently high level of investment in basic research can't help but enhance Japan's image as a tempting destination for foreign scientists looking to expand their horizons...
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