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PresentDay

Timestamp:: 2014-11-24T10:56:05+01:00 (9 years ago)
Author:: luyssaert
Comment:: --

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Documentation/UserGuide/PresentDay

-                      v4
+                      v5
 Before setting up a present day simulation, a pre-industrial run will be required to check the radiation balance at the top of the atmosphere. You can find some extra information on the topic at http://forge.ipsl.jussieu.fr/orchidee/wiki/HowTo/VerifyClimate. The basic idea is that for a pre-industrial run the net radiation at the top of the atmosphere should be close to zero. If this is not the case then the albedo of the oceans can be adjusted to mimic several atmospheric processes which are not accounted for. The setting of the variable pmagic that was required to produce a pre-industrial run with zero net-radiation at the top of the atmosphere is also the value for pmagic that needs to used in the present day simulation.
 The aim is to run a 20 year long equilibrium simulation for the year 2011. Orchidee off-line line was used to simulate the surface area in 2011 and now we want to know how the climate looked liked for such a surface. The coupled run is zoomed over Europe, nudged at the edges of Europe uses the CWRR (a.k.a. 11-layer) hydrology and all the DOFOCO features. A set of coupled pre-industrial runs demonstrated that the net-radiation at the top of the atmosphere was zero for a pmagic = XXX.
+Background of this set-up: The aim is to run a 20 year long equilibrium simulation for the year 2011. Orchidee off-line line was used to simulate the surface area in 2011 and now we want to know how the climate looked liked for such a surface. The coupled run is zoomed over Europe, nudged at the edges of Europe uses the CWRR (a.k.a. 11-layer) hydrology and all the DOFOCO features. A set of coupled pre-industrial runs demonstrated that the net-radiation at the top of the atmosphere was close to zero (0.2 Wm2 over 15 years with a monthly std 5.4 Wm2 for a pmagic = 0.000).
 == The boundary conditions ==
 LMDZOR was installed twice to avoid any confusion between the boundary files of the pre-industrial and the present day simulations. Hence, one installation will be used for the pre-industrial runs (and will thus use the pre-industrial boundary conditions), the other installation is to be used for present day simulations. For both sets of simulations an AMIP set-up was chosen. This set-up comes with acceptable BC between 1870 and 2100 which allows us to focus on the climate and reduce issues with sea surface temperature, see ice and aerosol concentrations. So copy the amip config.card to define the job that will create the BC
+LMDZOR was installed twice to avoid any conflicts between the boundary files of the pre-industrial and the present day simulations. Hence, one installation will be used for the pre-industrial runs (and will thus use the pre-industrial boundary conditions), the other installation is to be used for present day simulations. For both sets of simulations an AMIP set-up was chosen. This set-up comes with acceptable BC between 1870 and 2100 which allows us to focus on the climate and reduce issues with sea surface temperature, sea ice and aerosol concentrations. So copy the amip config.card to define the job that will create the BC
 {{{
 cd config/LMDZOR_v5.2/
 …
 }}}
  (3) There is no need to manually create a directory for this experiment. When you use ./../../util/ins_job the script will create a directory with a copy of the config.card as well as the COMP, DRIVER and PARAM folder.
+We want a 30-year equilibrium run but if we really use the boundary conditions from 1980 to 2010 we won't get anything near to equilibrium given that this is the period in which climate change became very obvious. So we limited the variation by copy the boundary conditions from 2008 to 2012 and cycling over these files to obtain a pseudo-chronology for 1981 to 2010. This time series was aligned on 2010 (2010->2010, 2009->2009, 2008->2008, 2012->2007, 2011->2006, 2010->2005, etc). The cyclic boundary conditions for ocean surface temperature and sea ice extent are stored at /ccc/work/cont003/dofoco/dofoco/INPUT_FILES/OCEAN_COMP. The same adjustments were made for the boundary condition files for ozone. These files can be found at XXX.
 The following, further, changes were made to the COMP/lmdz.card:
 …
 }}}
  (2) In the DRIVER/lmdz.driver it is specified that in the absence of the Oasis coupler, which is the case for LMDZOR, the ocean is forced. Hence the need of SST and sea ice files for all years in the experiment.
  (3) Most likely this is redundant at this stage but better safe than sorry so in PARAM/run.def set
 {{{
 VEGET=y
 }}}
 Now the ELI-128x118x39-2010 can be launched. It takes about 70 seconds per year so in this example it will take over 30 minutes to complete this 30-year job
 {{{