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Create Z-axis description files for hybrid level model data

Added by Alan Zhang over 10 years ago

Hi,

I am trying to transform my met data in hybrid level to pressure level. First I need to create Z-axis description files since in the hybrid-level data they didn't have.

When I use "ncdump temp2.nc", I have the following variables:

"dimensions:
lon = 144 ;
lat = 90 ;
lev = 48 ;
ilev = 49 ;

float lev(lev) ;
lev:long_name = "ref full pressure level" ;
lev:units = "mb" ;
lev:cartesian_axis = "Z" ;
lev:positive = "down" ;
double ilev(ilev) ;
ilev:positive = "down" ;
ilev:cartesian_axis = "Z" ;
ilev:units = "mb" ;
ilev:long_name = "ref half pressure level" ;
float hybi(ilev) ;
hybi:cell_methods = "time: point" ;
hybi:units = "none" ;
hybi:long_name = "sigma coordinate at layer midpoints" ;
float hybm(lev) ;
hybm:long_name = "sigma coordinate at layer midpoints" ;
float hyai(ilev) ;
float hyam(lev) ;
"

So the* hyai equals*: 9.869233e-06, 2.661949e-05, 5.103735e-05, 8.778238e-05, 0.0001406158,
0.0002178295, 0.0003317329, 0.0004982083, 0.0007382179, 0.001079699,
0.001559384, 0.002224931, 0.003137386, 0.00437398, 0.006031242,
0.008228413, 0.01111112, 0.01485524, 0.01967094, 0.02580669, 0.03355326,
0.0432476, 0.05527629, 0.07007877, 0.08814984, 0.1100416, 0.1363648,
0.1677889, 0.2050414, 0.2365392, 0.2519383, 0.2533553, 0.2428749,
0.2234445, 0.1988368, 0.1724909, 0.1466555, 0.1225258, 0.1006804,
0.08133731, 0.06448983, 0.0499993, 0.03765711, 0.02722529, 0.01846184,
0.01113584, 0.005038044, 0, 0

hyam equals: 1.824436e-05, 3.882842e-05, 6.940987e-05, 0.0001141991, 0.0001792226,
0.0002747811, 0.0004149706, 0.0006182131, 0.0009089587, 0.001319542,
0.001892157, 0.002681158, 0.003755683, 0.005202611, 0.007129828,
0.009669766, 0.01298318, 0.01726309, 0.02273881, 0.02967997, 0.03840043,
0.04926194, 0.06267753, 0.0791143, 0.09909575, 0.1232032, 0.1520769,
0.1864151, 0.2207903, 0.2442388, 0.2526468, 0.2481151, 0.2331597,
0.2111406, 0.1856638, 0.1595732, 0.1345906, 0.1116031, 0.09100886,
0.07291357, 0.05724457, 0.0438282, 0.0324412, 0.02284357, 0.01479884,
0.008086944, 0.002519022, 0 ;

So I want to ask when I create the Z-axis description files, how should I create the "vct"? The numbers of "vct" requires two times level plus 2.

zaxistype = hybrid
size = 48
levels = 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 48
vctsize = 98
vct = hyai&hybi? or
hyam&hybm?


Replies (1)

RE: Create Z-axis description files for hybrid level model data - Added by Uwe Schulzweida over 10 years ago

The vertical coordinate table (vct) needs the coefficients a and b from hyai and hybi.

    (1-1/1)