Changes between Version 58 and Version 59 of Documentation/UserGuide/PreIndSim

Timestamp:

2014-11-21T15:34:28+01:00 (10 years ago)

Author:

luyssaert

Comment:

--

Documentation/UserGuide/PreIndSim

@@ -264 +264 @@
 }}}
 
-Ideally wind fields for the year 1750 should be used for the pre-industrial run. However, ERAI data only start in 1958 so such files do not exist. Consequently, the 1980 to 2011 wind fields are used to nudge the pre-industrial simulation. the assumption we make here is that the winter patterns outside the nudged area have not changed dramatically between 1980 and 1750. For a strongly zoomed simulation over Europe that is probably an acceptable assumption. The years 1980 to 2011 have been prepared for the 128x118 zoomed grid and are stored at /ccc/work/cont003/dsm/p86ipsl/IGCM/BC/ATM/LMDZ/LMD128118/NUDGE_FILES/ERAI. If you are not using a zoomed grid that has been used previously, or you want to use the 128*118 grid for different years, you will have to prepare your own nudging files.  ERAI nudging files for wind (u and v) can be interpolated to the zoomed grid using the method described here : ​[https://forge.ipsl.jussieu.fr/igcmg/wiki/platform/en/documentation/I_modeles/B_LMDZ#Interpolationofnudgefiles]. Note that you must be in the group subipsl to have the permission to access these files. Contact Anne Cozic for TGCC to be added to subipsl. 
+Ideally wind fields for the year 1750 should be used for the pre-industrial run. However, ERAI data only start in 1958 so such files do not exist. Consequently, the 1980 to 2011 wind fields are used to nudge the pre-industrial simulation. the assumption we make here is that the wind patterns outside the nudged area have not changed dramatically between 1980 and 1750. Because we want to calculate the difference in climate between 1750 and 2010 it is more important to make sure that our wind fields come from the phase in NOA. If not, the change in climate that will be assigned to our treatment could be just due to a change in NOA. For a strongly zoomed simulation over Europe that is probably an acceptable assumption. The years 1980 to 2011 have been prepared for the 128x118 zoomed grid and are stored at /ccc/work/cont003/dsm/p86ipsl/IGCM/BC/ATM/LMDZ/LMD128118/NUDGE_FILES/ERAI. If you are not using a zoomed grid that has been used previously, or you want to use the 128*118 grid for different years, you will have to prepare your own nudging files.  ERAI nudging files for wind (u and v) can be interpolated to the zoomed grid using the method described here : ​[https://forge.ipsl.jussieu.fr/igcmg/wiki/platform/en/documentation/I_modeles/B_LMDZ#Interpolationofnudgefiles]. Note that you must be in the group subipsl to have the permission to access these files. Contact Anne Cozic for TGCC to be added to subipsl. 
 
 We still need to tell the model which nudging files it should use. This requires a change to COMP/lmdz.card so that libIGCM knows to copy the files before the run. Note that here we substitute the argument ${year} by ${year+130} so we will run the simulation from 1750 to 1780 (as specified in the config.card) but use the wind fields from 1980 to 2000 during the 20 years of the equilibrium climate experiment.