Modify start Files - Revision history

Martin.turbet at 09:10, 4 February 2026

2026-02-04T09:10:09Z

Martin.turbet: /* Using newstart.e routine */

2023-11-07T15:49:07Z

‎Using newstart.e routine

Martin.turbet: /* Using Python scripts */

2023-11-07T15:46:25Z

‎Using Python scripts

Martin.turbet: /* Using Python scripts */

2023-11-07T15:46:08Z

‎Using Python scripts

Martin.turbet: /* Using Python scripts */

2023-11-07T15:43:44Z

‎Using Python scripts

Martin.turbet: /* Using Python scripts */

2023-11-07T15:43:22Z

‎Using Python scripts

Martin.turbet: /* Using Python scripts */

2023-11-07T15:43:07Z

‎Using Python scripts

Martin.turbet: /* Using Python scripts */

2023-11-07T15:38:34Z

‎Using Python scripts

Martin.turbet: /* Using newstart.e routine */

2023-11-07T15:38:12Z

‎Using newstart.e routine

Martin.turbet at 15:35, 7 November 2023

2023-11-07T15:35:45Z

← Older revision		Revision as of 09:10, 4 February 2026
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	Note 1: we invite you to go through all existing options of ''newstart.e'' to get an idea of which variables can be modified.		Note 1: we invite you to go through all existing options of ''newstart.e'' to get an idea of which variables can be modified.
−	Note 2: if the option you want does not exist, you can create your own in the ''newstart.e'' routine by modifying the LMDZ.GENERIC/libf/dynphy_lonlat/~~phystd~~/newstart.F fortran file. You can easily copy and adapt existing examples. Once the changes have been made, you need to recompile the ''newstart.e'' routine and run it!	+	Note 2: if the option you want does not exist, you can create your own in the ''newstart.e'' routine by modifying the LMDZ.GENERIC/libf/dynphy_lonlat/phygeneric/newstart.F fortran file. You can easily copy and adapt existing examples. Once the changes have been made, you need to recompile the ''newstart.e'' routine and run it!

← Older revision		Revision as of 15:49, 7 November 2023
Line 72:		Line 72:
	This routine creates ''restart.nc'' and ''restartfi.nc'' files that can be copied into ''start.nc'' and ''startfi.nc'', respectively, and used as a new initial conditions for the Generic PCM.		This routine creates ''restart.nc'' and ''restartfi.nc'' files that can be copied into ''start.nc'' and ''startfi.nc'', respectively, and used as a new initial conditions for the Generic PCM.

−	Note: you can create your own ~~options~~ in the ''newstart.e'' routine by modifying the LMDZ.GENERIC/libf/dynphy_lonlat/phystd/newstart.F fortran file. You can easily adapt existing examples. Once the changes have been made, you need to recompile the ''newstart.e'' routine and run it!	+	Note 1: we invite you to go through all existing options of ''newstart.e'' to get an idea of which variables can be modified.
		+	Note 2: if the option you want does not exist, you can create your own in the ''newstart.e'' routine by modifying the LMDZ.GENERIC/libf/dynphy_lonlat/phystd/newstart.F fortran file. You can easily copy and adapt existing examples. Once the changes have been made, you need to recompile the ''newstart.e'' routine and run it!

@@ Line 47: / Line 47: @@
 The routine creates a ''restartfi.nc'' that can be copied into a ''startfi.nc'' and used as a new initial condition for the model.
-However, to make more advanced modifications, it is sometimes necessary to switch to another, more advanced method (see below). For instance, to modify the 3D atmospheric temperature field, it is necessary to compute the potential temperature, which requires the use of the Exner function. As this operation is not trivial, we recommend to use the ''newstart.e'' routine (see below).
+However, to make more advanced modifications, it is sometimes necessary to switch to another, more advanced method (see below). For instance, to modify the 3D atmospheric temperature field, it is necessary to compute and modify the potential temperature, which requires the use of the Exner function. As this operation is not trivial, we recommend to use the ''newstart.e'' routine (see below).
 == Using newstart.e routine ==

@@ Line 47: / Line 47: @@
 The routine creates a ''restartfi.nc'' that can be copied into a ''startfi.nc'' and used as a new initial condition for the model.
-However, to make more advanced modifications, it is sometimes necessary to switch to the other method (see below). For instance, to modify the 3D atmospheric temperature field, it is necessary to compute the potential temperature, which requires the use of the Exner function. As this operation is not trivial, we recommend to use the ''newstart.e'' routine (see below).
+However, to make more advanced modifications, it is sometimes necessary to switch to another, more advanced method (see below). For instance, to modify the 3D atmospheric temperature field, it is necessary to compute the potential temperature, which requires the use of the Exner function. As this operation is not trivial, we recommend to use the ''newstart.e'' routine (see below).
 == Using newstart.e routine ==

@@ Line 34: / Line 34: @@
 for i in range(0,len(physical_points),1):
      if(lat[i]*180./np.pi >= 0.):
-         new_tsurf[I]=350. # north hemisphere
+         new_tsurf[i]=350. # north hemisphere
      else:
-         new_tsurf[I]=250. # south hemisphere
+         new_tsurf[i]=250. # south hemisphere
 # CREATE THE NEW NETCDF TOPOGRAPHY FILE

@@ Line 31: / Line 31: @@
 # LOOP TO MODIFY THE VARIABLES
 # EXAMPLE - FIXED TEMPERATURES IN THE NORTH AND SOUTH HEMISPHERES
 for i in range(0,len(physical_points),1):

@@ Line 9: / Line 9: @@
 We have developed simple Python routines to easily modify ''start.nc'' and ''startfi.nc'' files. This requires the use of the xarray library.
-In the example below, we modify the surface temperatures (stored in the ''startfi.nc'' file) to arbitrarily fix them to 350K in the North hemisphere, and 250K in the South hemisphere of the planet.
+In the simple example below, we modify the surface temperatures (stored in the ''startfi.nc'' file) to arbitrarily fix them to 350K in the North hemisphere, and 250K in the South hemisphere of the planet.
 <syntaxhighlight lang="python">

← Older revision		Revision as of 15:38, 7 November 2023
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	</syntaxhighlight>		</syntaxhighlight>

−	This routine creates ''restart.nc'' and ''restartfi.nc'' files that can be copied into ''start.nc'' and ''startfi.nc'', respectively, and used as a new initial conditions for the ~~model~~.	+	This routine creates ''restart.nc'' and ''restartfi.nc'' files that can be copied into ''start.nc'' and ''startfi.nc'', respectively, and used as a new initial conditions for the Generic PCM.
		+
		+	Note: you can create your own options in the ''newstart.e'' routine by modifying the LMDZ.GENERIC/libf/dynphy_lonlat/phystd/newstart.F fortran file. You can easily adapt existing examples. Once the changes have been made, you need to recompile the ''newstart.e'' routine and run it!

← Older revision		Revision as of 15:35, 7 November 2023
Line 72:		Line 72:
	</syntaxhighlight>		</syntaxhighlight>

−		+	This routine creates ''restart.nc'' and ''restartfi.nc'' files that can be copied into ''start.nc'' and ''startfi.nc'', respectively, and used as a new initial conditions for the model.
−
−	~~When you execute newstart, you can use both a~~ ''~~start2archive'' file or the start files (''start~~.nc'' and ''~~startfi~~.nc''~~). Then the interactive interface will propose to modify several physical quantities such as the gravity, the surface pressure or the rotation of the planet. At the end of the procedure, two~~ files ~~are created: '' '''re'~~''start.nc'' and ~~'' '''re'~~''startfi.nc''~~. They can be renamed~~ and used as ~~start files to initialize~~ a new ~~simulation.~~
−
−
−	* Create file ''start_archive.nc'' with ''start2archive.e'' compiled at grid resolution 64×48×32 using old file ''z2sig.def'' used previously
−	* Create files ''restart.nc'' and ''restartfi.nc'' with ''newstart.e'' compiled at grid resolution 32×24×25, using a new file ''z2sig.def'' (more details below on the choice of the ''z2sig.def'').
−	* While executing ''newstart.e'', you need to choose the answer '0 - from a file start_archive' and then press enter to all other requests.
−
−
−	~~else if (trim(modif) .eq. 'isotherm') then~~
−
−	~~write(,)'Isothermal temperature of the atmosphere,~~
−	~~& surface and subsurface'~~
−	~~write(,) 'Value of this temperature ? :'~~
−	~~203 read(,,iostat=ierr) Tiso~~
−	~~if(ierr.ne.0) goto 203~~
−
−	~~tsurf(1:ngridmx)=Tiso~~
−
−	~~tsoil(1:ngridmx,1:nsoilmx)=Tiso~~
−
−	~~Tset(1:iip1,1:jjp1,1:llm)=Tiso~~
−	~~flagtset=.true.~~
−
−	~~t(1:iip1,1:jjp1,1:llm)=Tiso~~
−	~~!! otherwise hydrost. integrations below~~
−	~~!! use the wrong temperature~~
−	~~!! -- NB: Tset might be useless~~
−
−	~~ucov(1:iip1,1:jjp1,1:llm)=0~~
−	~~vcov(1:iip1,1:jjm,1:llm)=0~~
−	~~q2(1:ngridmx,1:llm+1)=0~~
−
−
−	~~if (flagtset) then~~
−	~~DO l=1,llm~~
−	~~DO j=1,jjp1~~
−	~~DO i=1,iim~~
−	~~teta(i,j,l) = Tset(i,j,l) * cpp/pk(i,j,l)~~
−	~~ENDDO~~
−	~~teta (iip1,j,l)= teta (1,j,l)~~
−	~~ENDDO~~
−	~~ENDDO~~
−
−	~~A few options to do that:~~
−	* use existing topographic data for solar system objects. We have already formatted the data for ~~most solar system objects, so please ask someone in~~ the ~~team if your topography map is not already here: https://web.lmd.jussieu.fr/~lmdz/planets/LMDZ.GENERIC/datagcm/surface_data/~~
−	* use your own data files
−
−	~~You can also derive data files by digitalizing images. See below an example:~~
−
−	~~[[File:rico_topography.png\|thumb\|rico_topography.png]]~~
−
−	~~<syntaxhighlight lang="python">~~
−	from numpy import *
−	~~import numpy as np~~
−	~~import matplotlib.pyplot as mpl~~
−	~~import math~~
−	~~from PIL import Image~~
−
−	~~# Here we first digitalize a png image name "rico_topography.png"~~
−
−	~~image = Image.open('rico_topography.png') # For simplicity, we work here in a 360 longitude pixels x 180 latitude pixels~~
−	~~pix = image.load()~~
−	~~image_width, image_height = image.size~~
−	~~topography_data=np.zeros((image_width, image_height),dtype='f')~~
−
−	~~# Here we convert the pixels into some rules for the elevation map~~
−
−	~~for i in range(0,image_width,1):~~
−	~~for j in range(0,image_height,1):~~
−	~~if(pix[i,j][0]<1. and pix[i,j][1]<1. and pix[i,j][2]<1.):~~
−	~~topography_data[i,j]=5.~~
−	~~else:~~
−	~~topography_data[i,j]=0.~~
−
−	~~# Here we write the topography map into an ascii file~~
−
−	~~name_file='rico_topography.txt'~~
−
−	~~with open(name_file, 'w') as f1:~~
−	~~for j in range(0,image_height,1):~~
−	~~for i in range(0,image_width-1,1):~~
−	~~print("{:12.5e}".format(topography_data[i,j]),file=f1,end=' ')~~
−	~~print("{:12.5e}".format(topography_data[image_width-1,j]),file=f1,end='\n')~~
−	~~</syntaxhighlight>~~
−
−
−	~~This requires the use of the PIL library, and the rico_topography.png file~~.