[Thread Prev][Thread Next][Index]

[ferret_users] Problem with irregular (latitude) grid in pyferret



Dear all,
I wish you a wonderful year 2023.
I would like to point out a problem I am encountering with pyferret (7.5 and 7.63).
I am working with some ocean model outputs from CROCO.

I have extracted one time-step and 100 longitude points of sea surface temperature in the attached file (ENSmean_tropatl_surf_avg_Y2021_temp1.nc).

You will see that my latitude is slightly irregular extending from 30°S to
               eta_rho:long_name = "latitudes rho" ;
               eta_rho:units = "degree_north" ;
 eta_rho = -30, -29.92783, -29.85561, -29.78334, -29.71101, -29.63863,
    ...
   8.902213, 8.984543, 9.066854, 9.149145, 9.231419, 9.313673, 9.395907,  
   9.478123, 9.560319, 9.642494, 9.72465, 9.806787, 9.888902, 9.970997,  
   10.05307 ;


I am just loading the file in Pyferret  (7.5 or 7.63) and saving it (no transformation whatsoever):
cancel data/all; cancel var/all
set memory/size=5000; cancel mode upcase
use
ENSmean_tropatl_surf_avg_Y2021_temp1.nc
let/title="TEMPf" TEMPf=TEMP
save/clobber/file=
ENSmean_tropatl_surf_avg_Y2021_temp1_pyf763.nc TEMPf

In the new file, the latitude axis has been reworked by ferret and now the attributes are:
        float eta_rho(eta_rho) ;
               eta_rho:long_name = "latitudes rho" ;
               eta_rho:units = "degrees_north" ;
               eta_rho:point_spacing = "uneven" ;
               eta_rho:axis = "Y" ;
               eta_rho:standard_name = "latitude" ;
               eta_rho:bounds = "eta_rho_bnds" ;
       float eta_rho_bnds(eta_rho, bnds) ;


NOTE that the values of the variable eta_rho remain exactly the same as in the original file:
 eta_rho = -30, -29.92783, -29.85561, -29.78334, -29.71101, -29.63863,
   ...
   8.902213, 8.984543, 9.066854, 9.149145, 9.231419, 9.313673, 9.395907,  
   9.478123, 9.560319, 9.642494, 9.72465, 9.806787, 9.888902, 9.970997,  
   10.05307 ;


---> Surprisingly, when I load the new file in pyferret (7.5 or 7.63) and plot the SST map, the latitude still has 500 points, but extends from 30°S to 6°N... ????
use ENSmean_tropatl_surf_avg_Y2021_temp1_pyf763.nc
shade tempf

---> When I load ENSmean_tropatl_surf_avg_Y2021_temp1_pyf763.nc in old ferret v6.71the map is correct (from 30°S to
               eta_rho:long_name = "latitudes rho" ;
               eta_rho:units = "degree_north" ;
               eta_rho:point_spacing = "uneven" ;
               eta_rho:axis = "Y" ;
               eta_rho:bounds = "eta_rho_bnds" ;
       double eta_rho_bnds(eta_rho, bnds) ;

Does anyone know what is happening? In the meantime, I will remove the eta_rho_bnds attribute with NCO.

Have a nice day,

Serena


.¸. , . .·´¯`·
 ><(((º>     `·.¸.·´¯`·...¸><(((º>¸.¸. , . .·´¯`· ><(((º> .
`·.¸.·´¯`·...¸><(((º>                                                    .
                                                                                  .
  Serena ILLIG-THEVENIN       LEGOS/IRD             .
                                                                                  .
ENSmean_tropatl_surf_avg_Y2021_temp1_f671.nc
Description: Cdf file

Attachment: ENSmean_tropatl_surf_avg_Y2021_temp1.nc
Description: Cdf file

Attachment: ENSmean_tropatl_surf_avg_Y2021_temp1_pyf763.nc
Description: Cdf file


[Thread Prev][Thread Next][Index]