Solution: COHERENS sigma to meters z coordinate

[Francisco J Campuzano Guillen <G.F.Campuzano@xxxxxxxxxx>]

First of all, I wish to thank the help and advice given by
Paul Farrar and Ansley Manke through the ferret users list.

The solution of how to represent the results from a test case of the 
COHERENS model from sigma coordinates to depth coordinates with 
ferret, v5.41 for windows, is attached. As an example I used the 
Front A test case.

Best regards,

			Francisco J. Campuzano

----------------------------------------
Francisco J Campuzano Guillén
Email: G.F.Campuzano@hull.ac.uk
University of Hull

bash-2.05$ ferret
        NOAA/PMEL TMAP
        FERRET v5.41
        cygwin 1.3.x - 08/30/02
        19-Feb-03 15:05

yes? set data frontA_1.out3U.cdf
 *** NOTE: Units on axis "z" are not recognized: sigma_level
 *** NOTE: They will not be convertible:
yes? show d
     currently SET data sets:
    1> C:\TMAP\fer_dsets\data\frontA_1.out3U.cdf  (default)
 name     title                             I         J         K         L
 DEP      water_depth                      1:50      1:1       ...       ...
 U2       U3D                              1:50      1:1       1:20      1:13
 V2       V3D                              1:50      1:1       1:20      1:13
 W2PHYS   W3D                              1:50      1:1       1:20      1:13
 CONCN    Contaminant                      1:50      1:1       1:20      1:13

yes? let bb= dep + 0*concn[l=1]
yes? let zz= (z-1)*bb
yes? stat zz

             (Z-1)*BB
             X (km): 0 to 50
             Y (km): 0.5
             Z (sigma_level): -0.0000000009313 to 1
             T (days): 0
             DATA SET: C:\TMAP\fer_dsets\data\frontA_1.out3U.cdf

 Total # of data points: 1000 (50*1*20*1)
 # flagged as bad  data: 0
 Minimum value: -48.75
 Maximum value: -0.75
 Mean    value: -20.4 (unweighted average)
 Standard deviation: 13.02
yes? plot/i=12/j=1 zz                    !you should get an increasing line!
yes? def axis/z=0:-50:.1/depth z100      !defines a new axis with the scale in meters!
yes? let znew = z[gz=z100]
yes? let concn_depth = ZAXREPLACE (concn,zz,znew)   !replace the s-coordinate for the z-coord.!
yes? fill/l=1 concn_depth                           !the graph is upside-down,z is negative!
yes? fill/l=1/vlimits=0:-50:1 concn_depth           !defines how to represent the z-axis!