Re: multi-netcdf files for ensemble simulations

[Rob Scott <rscott@xxxxxxxxxxxxxxxxxx>]

Hi Sonia

I can't remember if I've had this particular problem, but I do have a 
script that I believe is a solution. I concatenate a bunch of NetCDF files, 
but join them on the t-axis. Please see script below. (I imagine it's 
straightforward to change this script to work with the z-axis.)

Hope this helps,
Rob

Rob Scott
Research Associate
Institute for Geophysics
University of Texas at Austin
4412 Spicewood Springs Rd.
Building 600
Austin, TX
78759

Office: +1-512-471-0375


> Dear Ferreters,
>
> Hopefully someone already found a solution to the following problem:
>
> I have a series of NetCDF files entailing output from GCM ensemble 
> simulations.
> In order to analyse the data, it would help me to be able to concatenate the
> NetCDF files on one axis, with each axis "level" corresponding to one 
> member of
> the ensemble (I thought of using the Z axis for this as I only have surface
> fields).
>
> I did a few tests following the instructions from Chap. 10  Sec. 2, 
> however, the
> output file does never entail more than one z-level (see attachment). Did 
> anyone
> have this problem before and manage to find a solution?
>
> Thank you very much!
> Sonia


!------------------------------------------------------------------------------ 
! join ssh files along the time axis
!------------------------------------------------------------------------------ 

! must specify:
SET REGION/Y=8N:60N/X=120E:260E
DEFINE SYMBOL out_file = ssha_aviso_NP.cdf

!------------------------------------------------------------------------------ 
! ssh, access many files:
!------------------------------------------------------------------------------ 
let names = {spawn:"ls 
/rbs0/Altimeter_data/Aviso/MERCATOR/hh_msla_oer_merged_h_*"}
!------------------------------------------------------------------------------ 
! setup & clobber an empty NetCDF file
!------------------------------------------------------------------------------ 
SET DATA " `names[i=1]` "
DEFINE AXIS/T=15627:19036:7/UNITS=DAYS taxis
DEFINE GRID/LIKE=grid_0001/T=taxis grid_aviso
LET/TITLE="AVISO Sea Surface Height Anomaly"/UNITS=m \
ssha = (1/0) * x[G=grid_aviso] * y[G=grid_aviso] * t[G=grid_aviso]
SET MEMORY/SIZE=268
SAVE/CLOBBER/FILE=($out_file)/RIGID/LLIMITS=1:488 ssha

!------------------------------------------------------------------------------ 
! required variable definitions
!------------------------------------------------------------------------------
LET dummie = x[G=grid_aviso] * y[G=grid_aviso] * t[G=grid_aviso]
! (change ssha from cm to m)
LET ssha_tmp = grid_0001/100
!------------------------------------------------------------------------------ 
! now append the rest
!------------------------------------------------------------------------------
REPEAT/k=1:488 (LET a = names[i=`k`]; \
SET DATA/regulart " `a` "; \
DEFINE AXIS/T=15627:19036:7/UNITS=DAYS taxis ;\
DEFINE GRID/LIKE=grid_0001/T=taxis grid_aviso ;\
LET/TITLE="AVISO Sea Surface Height Anomaly"/UNITS=m ssha = 
RESHAPE(ssha_tmp,dummie[L=`k`]); \
SAVE/APPEND/FILE=($out_file)/RIGID/LLIMITS=1:488 ssha[L=`k`]; \
CANCEL DATA /ALL ;\
CANCEL AXIS/ALL)
!------------------------------------------------------------------------------ 
! did it work?
! remove def of ssha so as to not confuse it
!------------------------------------------------------------------------------ 
CANCEL VAR ssha
USE ($out_file)
SHOW DATA/VAR