'''Nov 2011'''
I've briefly written up the (minor) changes to xfxwb, and the top-level friction variation (xfhcc) for Geoscientific Model Development:
[[http://www.geosci-model-dev-discuss.net/4/3047/2011/gmdd-4-3047-2011.html | XFXWB and XFHCC update paper]]
so it's now available to all as a discussion paper.
Also following on from Till's analysis, it seems that the diagnostics for d(tracer)/dt due to advection are rather misleading/wrong in FAMOUS - they're a bit muddy in all UM4.5 code actually. There's code for diagnosing both U.grad(T) and div(UT) in there, with the default giving U.grad(T), for some reason - the source field is actually updated using div(UT), so U.grad(T) will not show how the model field has really evolved. [=HadCM3=] had a rather blunt override mod to put div(UT) into the diagnostic again which was not carried across to the newer UM4.5 advection mods used in FAMOUS. It's pretty straightforward to edit the advect.f file to show div(UT) in FAMOUS, or ask me for a "fixed" mod you can use.
'''Sep 2011'''
Till Kuhlbrodt has been looking at the Southern Ocean under climate change across a range of models, and noted that xfxwb FAMOUS was alone in not showing a strengthening of the SO westerlies under CO2 forcing. A quick bit of analysis shows that the (zonal, at least) wind changes everywhere in FAMOUS are generally inconsistent with CO2-forced [=HadCM3=], and seem to all be linked to the unrealistic top layer. Introducing ''just'' the simple top-level friction into xfxwb seems to solve this: CO2-forced changes in the vertical wind structure look much more like other models, and surface wind changes poleward of 40degrees, especially in the Southern Ocean, look like [=HadCM3=]. (Sub)Tropical wind changes are still inconsistent (but smaller), and there are knock-on effects on the control climate in this model: the seasonal cycle of temperatures in the northern hemisphere is improved, the ACC is slowed even more than before, the AMOC weakens by a few Sv and deepens. I'm conflicted whether to make this a standard version, or stick to the original plan and wait for all the bells and whistles of xfhcy to be tuned and released.
'''Aug 2011'''
There's some significant FAMOUS development going on (alebit slowly), so I'll go back to trying to keep these pages up-to-date with things as they occurr. I guess there's four things that ought to be flagged up:
* xfxwb
-> this is a bug-fixed version of the model described in the GMD (2008) paper - see FAMOUSStandardVersions. Some runs have been done for the [[http://www.climate.uvic.ca/EMICAR5|EMICmip]] contribution to AR5, and this is actually the version that was used in the [[http://centaur.reading.ac.uk/20384|Hawkins et al]] AMOC hysteresis paper and my long glacial transient runs - an update to the GMD paper is in the works.
* xfhcy (FAMOUS*)
-> this is a new release candidate for the long awaited MOSES2.2 (closed carbo cycle, dynamic vegetation) version of FAMOUS - see FAMOUSStandardVersions. The biggest new science over previous versions is the top-level friction detailed below. Tuning ensembles have been run by Jonny Williams@Bristol, so a useful release should be forthcoming in the near future
* Cold-climate stability/Top-level winds/Timestepping/Filtering
-> round about Christmas 2010 I decided to have a proper look at the stability issues that plagued FAMOUS when running colder-than-modern climates. There are more [[CurrentWorkFiltering|details below]], but it all seems to link in with the 1sweep/2sweep timestepping mystery, the winter cold bias and pretty much everything that's wrong with FAMOUS (well, almost), and it's trivial to fix. There's a hack fix for current release versions (stratcap.mod) that just improves stability, and a better, science fix (rayleigh_fric.mod) that improves the climate as well, but requires the climate to be retuned. stratcap.mod is included in [[FAMOUSStandardVersions|xfxwb]], rayleigh_fric.mod in [[FAMOUSStandardVersions|xfhcy]]
* Glimmer-CISM coupling
-> my new project involves improving the coupling between the UM and the Glimmer-CISM icesheet model - previous work has relied on the simple, annual PDD scheme and an outdated version of Glimmer. We will require the multilayer snow scheme from JULES (now technically incorporated into FAMOUS) and to code up subgridscale hypsometry, along with modifications to the Glimmer-UM interface. Hopefully this can all be done within the CESM framework being developed for Glimmer-CISM at Los Alamos. Watch this space.