Alastair McKinstry: Exoclimes: the diversity of planetary scientists
I'm just back from ExoClimes 2010: Exploring the Diversity of Planetary Atmospheres.
An excellent conference: the PDFs of the talks and posters are now online, and they are putting the videos of the
talks up soon. But in particular the organizers deserves thanks for bringing exoplanetary scientists and observers
together with climate modelers doing Earth (and Mars, Titan, Venus, ...) models.
Peter Cox on model complexity
The last talk on Friday was by Peter Cox on
Climate change and exoplanet sciences that was far better than expected for the "graveyard shift". One theme of the conference was the need for a 'heirarchy' of models, from simple energy-balance models to full circulation (GCM) models: using progressively more complex models to understand more bits of whats going on. Exoplanet workers mostly use simpler models, progressing now to GCMs, while Earth modellers are moving beyond GCMs to "Earth system" models including biology, etc. Peter pointed out the two styles of work: the exoplanet modelers are short of data, and risk being too speculative. We know little of what the planets are like, and concentrate on implementing physics in the models to see what they might be like. Earth modelers on the other hand are if anything swamped with data: the tendency here is to make the model fit the data, by adjusting parameters until it does so. The danger of this approach is that the model will then not work away from current present-Earth conditions.
Tim Lenton pointed out some work that was done with the Met Office model, where they took the radiative transfer part of the model and tested it for
other planets, and paleo-Earth conditions. The model blew up : it wasn't capable of x2 or x4 current CO2 levels. (This has since been corrected).
Over dinner there were interesting discussions on the different styles within the communities.
While the underlying GCMs used come from the Earth sciences,
its quite common within the exoplanetary community for a researcher to work on all parts of the model: dynamics
one day, radiative transfer the next. In Earth climate work people have become more specialized and someone
is a 'radiative transfer' person, and won't touch other parts of the code
(even if they can follow them in the huge codes we have today!).
On the other hand, there is a greater
tradition of model inter-comparison in Earth sciences, where we compare the model outputs to each other
for some known test cases (
Held & Suarez, the
CMIP5 project, etc.) Apart from some initial work by
Emily Rauscher, little has been done on this in exoplanetary models; it was agreed more of this would
be a good idea.
Radiative transfer (the interaction of 'sunlight' with the atmosphere, where it gets absorbed, scattered and re-radiated)
in particular seems to be an area that could benefit from this.
In this middle ground Francois Forget showed the work on the LMDZ model and
applying GCMs to terrestrial planets.
They've successfully applied this model to Mars, Titan, and partially to Venus (a much tougher problem, due to its heavy clouds
giving a long radiative timescale). There are problems with correctly explaining super-rotation though.
This is where the atmosphere rotates faster than the planet: on Venus for example the planet rotates every 243 days,
while the clouds rotate around the planet every 4 days.
Sebastian Lebonnois described
the possible mechanisms for Venus and Titan; Johnathan Mitchell so did some interesting work on this recently.
Different regimes are involved for different rotation rates of the planet.
Ralph Lorenz pointed out the lack of "real paleo-Earth" climate work at the moment. While geology has inspired
a lot of work on the
atmospheric composition,
what with the different gas mixtures (meaning earth-model radiative transfer codes don't work) and
the faster dynamics meaning super-rotation could apply (Earth's day was about 8 hours long in the Archean era), we don't have a model of the climate yet.
It looks like we should treat Earth as an exoplanet.
Peter Cox on model complexity
It is a while since we managed to get 
I'm back in town. After approximatly 4 full days of use, the first battery
bank dropped to 9 volts, my cutoff point for safe use. Which turned
out to be below the safe use point of my laptop power adapter, which burnt
out while I was busy listening to music and adding power-saving caching
stuff to my mpd setup. Irony not appreciated, world.
I decided to come back while the other bank is still relatively full.

I must admit, I do not really get the point of the ongoing discussion about having an official Facebook page. In my understanding it should be a source of information about Debian for Facebook users, technically a mirror of
Backlight control is one of those things that you'd think would be simple, but ha ha this is computing so of course it's an utter disaster and everything is a huge mess. There's three main classes of backlight control in the x86 world, all of which have drawbacks:
This took a bit of searching, so it's here for reference. I'm sure it'll catch out people who upgrade from Lenny to Squeeze as the initial presentation can be deeply mysterious and frustrating.
If you do care about having good samba packages in squeeze, you can
help.
If you're in a hurry and don't want to read the blah-blah, just skip
to the end of this story and read the last paragraph.
Thanks to the confidence of the release team, we (samba packagers)
have been "authorized" to upload samba 3.5.4 in unstable, thus
targeting having that version in squeeze.
Up to July, we were indeed targeting 3.4.8 for squeeze, on the
assumption that, as usual, samba upstream releases need some
maturation before being strong guarantee that no regression happens.
In July we were ready to move and finally upload in unstable the 3.5 packages we
kept in experimental until then. The final decision was to be taken
during DebConf10. It was roughly taken with Steve Langasek, but....I
couldn't upload immediately (most people know that working on major
packages during DebConf is a dream)...and had holidays afteer.
In the meantime, the freeze happened so we got theoretically
screwed...
Still, I could manage to convince the release team that long term
support for samba 3.5 will certainly be better than 3.4...and that
functionality in that version (particularly several Win7-related fixes
and a much improved code for printing support) and we got a notice
"please upload to unstable and come back to us in a few weeks".
That happened, finally.
So, now, we need YOU, samba users and admins, to test these
packages. Merging our packaging branches was hard (thanks, Steve
Langasek, for your help) and glitches are always possible. So, please
TEST these packages by installing samba, winbind, libsmbclient and
friends from unstable....and report bugs, preferrably the release
critical ones....
PS This post also gives me a chance to comment
on a so called
A long time ago, when I was first introduced to email, I was using the
Mail program from Unix. I quickly converted to Elm, then Mutt, which
were both better in terms of interface. Then I found out about Gnus,
and I wouldn't dream of letting it go now. However, Gnus has started
showing its age several times, and several times have I needed to
upgrade the way I was using it: first because I needed to sort and
split email, then because I took the sorting out of Gnus and into
Procmail for more advanced filtering (including spam filtering), then
because I switched to storing the emails on an IMAP server so I could
read them remotely from several computers. My setup as of a few days
ago was functional, but since I have grown over time to splitting
emails into several hundred folders, checking for new messages was
becoming more and more boring.
So it's time to jump in with all the cool kids and switch to a modern
solution: still Gnus of course, but with Dovecot, OfflineIMAP for
synchronisation, and let's add email searches into the mix while we're
at it. My web searches didn't turn up a simple step-by-step HOWTO,
but I assembled bits from different places, and here's my attempt at
documenting my new setup.
Goals
... or, 'yellow pages.be'. Or something.
I like it that there is an on-line version of the Belgian yellow
pages. Who wants to look up a phone number in a huge book, anyway? And
that's ignoring the fact that it isn't any good for the environment.
I also like it that the yellow pages are now no longer distributed by
default on paper. You can still get them, if you so wish, but you have
to explicitly request them.
Of course, searching an on-line database is also faster than flipping
through pages until you find what you're looking for. What's more, you
can limit your search to your location rather than whatever
shops just happen to be in the version of the book that is distributed
to your house. That makes it much more efficient, since rather than all
thousands of computer shops in the whole province, you'll find the
computer shops in your municipality. Or the ones that are in a radius
around your address, if you choose that option.
Rather, that would be the case. But for some
unfathomable
Italian
A few days ago I talked about
After a bit of work, I got the sheeva plug working the way I wanted it to. First of all, I grabbed a spare 1G USB flash disk I had laying around and installed Debian squeeze to it by following tbm s instructions here: