Tuesday, October 28, 2014

The new UKMO computer

I was thinking that this seems reasonable enough:

but then Mat Collins tweeted that it will "will also be used for making more reliable climate projections" which is a bit of a hostage to fortune. (Though technically, it may take so long to check this out that we never know if he is right or not).

Way back in the mists of time senior scientists at FRSGC (as it then was) imagined that their new superduper Earth Simulator would solve all the problems of climate change...

As for weather prediction, it's easy enough to demonstrate experimentally that higher resolution has the potential to improve performance (even though computer power is far from the only influential factor). So I expect they can claim quite confidently that the bigger computer will improve this.

Thursday, October 23, 2014

[jules' pics] falling water

As well as ocean swell, there are other after effects of storms. One is the amount of water falling in the water falls. I actually didn't know we live near a waterfall until this week. It is Scaleber Force, and only 1.3 miles from our house (although up a stupidly steep hill). I learned later that it is a top photography spot, so it is lucky that James encouraged me to take my camera along just in case there was something to see.
This photo was taken at the same place, looking downstream,

Posted By Blogger to jules' pics at 10/23/2014 06:55:00 PM

Tuesday, October 21, 2014

[jules' pics] Autumn colours

Another storm yesterday, and the autumn colours are not going to last much longer. Better blog them while I still can.
autumn leaves

Posted By Blogger to jules' pics at 10/21/2014 10:42:00 PM

Saturday, October 18, 2014

Friday, October 17, 2014

[jules' pics] ocean #2

The fun thing about the ocean, is that the waves can come quite a while after the weather. So, while the storm had blown over the day before, the sea was just getting going.



Posted By Blogger to jules' pics at 10/16/2014 09:35:00 PM

Thursday, October 16, 2014

[jules' pics] ocean #1

Some rain stopped us mountain biking on the way over to Scotland's east coast, but it had stopped by the time we got to the seaside.

seaside sunset

Posted By Blogger to jules' pics at 10/16/2014 09:31:00 PM

Tuesday, October 14, 2014

[jules' pics] autumn

My memories of autumn from when I were a lass are of slipping about on mushy brown leaves on the ground, and of wind, rain and days so dark you can barely see across the school hall. There must have been some climate change because we now have some sunny days with little hints of yellow and orange on many of the trees. It's nothing like Japan, obviously (many more degrees of climate change to go before we get there), but still...


Posted By Blogger to jules' pics at 10/14/2014 03:35:00 PM

Friday, October 03, 2014

Much ado about sensitivity

Well, perhaps not really very much ado. There's a new paper in Climate Dynamics, by Lewis and Curry, with a central sensitivity estimate of 1.6C with a 90% range of 1-4C, based on energy budget analyses over the instrumental period, updated to the present day, also taking account of the newer AR5 forcing estimates. I don't find it particularly exciting, the authors cite several recent papers with similar results including Aldrin and Otto et al. I wrote about those papers some time ago, and I think these posts (1, 2, 3) still stand. I've commented before on my objections to Lewis' method, and especially the sleight-of-words with which it is described, but (as I've also emphasised) I don't think this substantially affects the results in this application.

Clearly, the longer the relatively slow warming continues, the lower the estimates will go. And despite what some people might like to think, the slow warming has certainly been a surprise, as anyone who was paying attention at the time of the AR4 writing can attest. I remain deeply unimpressed by the way in which this embarrassment has been handled by the climate science insiders, and IPCC authors in particular. Their seemingly desperate attempts to denigrate anything that undermines their storyline (even though a few years ago the same people were using markedly inferior analyses of this very type to bolster it!) do them no credit.
One weakness of these energy-budget type of analyses, that I believe Lewis and others could easily address, is to demonstrate how well it works in application to GCM output. That is, can the method accurately diagnose the sensitivity of a model given equivalent information to that which we have for the real world? Aldrin et al addressed this rather briefly and in a very limited way, using a far stronger forcing scenario (1%pa CO2 enrichment) than what has occurred in reality. It would be easy to investigate the precision of the method, and whether it gives rise to any systematic biases, by using output from the more realistic 20th century simulations. It is also noteworthy that the Aldrin method struggles to cope with hemispheric differences, which may point to some limitations of the energy balance concept. While the climate system certainly does obey the fundamental conservation laws, supposedly “fixed” parameters (in simple models) are not actually constants in reality. And no matter now precisely we can determine the historical transient response to the current radiative imbalance, there will always be a bit of additional uncertainty in extrapolating that to an equilibrium 2xCO2 state.
Finally, it is also amusing to see Judith “we don't know anything” Curry to put her name to this new paper: it is unclear what she might have added, as Nic has been presenting analyses of this nature for some time now. But that's a minor matter.