GmapDoc website
Slogan du site
Descriptif du site
SURGERY : to determine a gaussian reduced grid (1999)
Article published on 1999
last modification on 3 November 2005

This procedure "surgery" is determining the number of longitudes for each latitude of a gaussian reduced grid, defined by :

  • the number of latitudes NDGL,
  • the maximum number of longitudes NDLON,
  • the truncation NSMAX.

The job is split in 2 parts :

  • first part is the computation of the Legendre polynomials onto a file (done by Arpege/128 bits)
  • second part is the computation of the reduced grid, after reading the Legendre polynomials file (done by a specific program, adapted from the subroutine surgri.F)

How to use it :

  • 1/ Copy the following file on VPP : mrpm602/rgrid/surgery and set your favourite values for NDGL, NDLON, NSMAX (Beware : set the nominal truncation, not twice its value : the procedure is doing by itself the multiplication by 2 !) Remark : this procedure works for quadratic grids ; if you are using non-quadratic grid, you should set for NSMAX the equivalent truncation you would have for a quadratic grid.
  • 2/ Submit the script
  • 3/ Enjoy the result on the *.o* file
  • 4/ ALWAYS congratulate or damn the builder at email adress

More about it ?

Then explore the directory mrpm602/rgrid on VPP, everything is public !