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Subsections


Input namelist and files

The grib2v5d namelist file contains two namelists: config, which determines the conversion procedure, and names, which specifies the input and output file names. Most of the namelist variables have a default value so that they may be not included in the file, but some of them are mandatory (see section 4.3).

The namelist config

The namelist config can contain the following scalar variables:
Name Type Meaning Default
numtimes INT number of time levels in output deduced from vector tabvar
numvars INT number of variables in output deduced from vector tabfth
compressmode INT Vis5d compress mode (number of bytes per datum, 1, 2 or 4) 1
typel INT input grib vertical level type for upper air fields deduced from grib file
vctype INT input grib type of hybrid vertical coordinate deduced from grib file
redfact INT linear reduction factor for the grid 1
fixedfth INT <0 to operate in ``forecast mode'', $\geq$0 to operate in ``analysis mode'' -1
itt INT position of temperature field in variables list 0
iqq INT position of specific humidity field in variables list 0
ivu INT position of x component of wind field in variables list 0
ivv INT position of y component of wind field in variables list 0
ivw INT position of z component of wind field in variables list 0
ips INT position of surface pressure field in variables list 0
ipt INT position of top-of-atmosphere pressure field in variables list 0
ipp INT position of pressure field in variables list 0
ipd INT position of pressure departure field in variables list 0
igo INT position of surface height or geopotential field in variables list 0
ire INT position of reciprocal of sigma field in variables list 0
izh INT position of half model level height (for output) in variables list 0
izf INT position of full model level height (for output) in variables list 0

Name Type Meaning Default
ptdef REAL top-of-atmosphere pressure value if not found in grib (Pa) 10000
fill_below LOG TRUE to fill below ground the fields defined up to the ground level TRUE
noproj LOG TRUE to avoid the use of Vis5d projection and define a generic horizontal coordinate FALSE
invertl LOG TRUE to scan the vertical level list backwards while reading input file TRUE
sounding LOG TRUE to produce ASCII formatted sounding output file FALSE

The values for typel are those from grib code table 3, so 100 for pressure levels, 103 for height levels, 107/108 for sigma levels/layers, 109/110 for hybrid levels/layers or 119/120 for eta levels/layers. If the value is not provided it is taken from the first upper-air field on H points found in the grib file (see next section). When temperature and specific humidity are used for computing geopotential height in the cases of sigma/eta/hybrid cordinates, the temperature is assumed to be on layers, regardless of what is specified in the namelist (this is generally true for the usual vertical staggering schemes used in numerical models).

The types of hybrid coordinates supported are standard pressure-normalised (like Lokal Modell, vctype=2) and Simmonds-Burridge surface pressure-normalised (like ECMWF model, vctype=1). If not specified vctype is automatically guessed with an heuristic algorithm.

Set redfact to a value greater than 1 in order to produce a smaller output and a faster display at the expense of a poorer resolution.

The variables itt, ... ire indicate the position, in the vector of model variables, of some key parameters; if their value is 0 it means that the corresponding parameter is not present.

The flag noproj disables the interpretation of the geographic projection of original data, so that a generic rectangular system is used; moreover a Vis5d topography file with the model orography is generated.

The namelist config can contain the following vectors dimensioned as numvars:
Name Type Meaning Default
varname CHAR() variable names for Vis5d none
tabvar INT() grib parameter indicator none
tab2ver INT() grib table 2 version -1
nl INT() number of input vertical levels for each variable none
lowlev INT() lowest input level -1 for each variable none
nzlev INT() number of output vertical levels for each variable n. of elements in vert_args or 1 if surface field
lowzlev INT() lowest output z level -1 for each variable contents of lowlev
gridtype INT() type of C-grid point for each variable (0=H, 1=U, 2=V) 0
cumulate INT() >0 to accumulate each field from beginning of forecast, <0 to subtract each field from the previous in time 0
const LOG() TRUE for fields that are constant in time FALSE
input LOG() TRUE for fields to be read from grib, FALSE for fields to be computed TRUE
output LOG() TRUE for fields that should be output TRUE

The names of the variables defined in the vector varname can take any value, however, to make sure that Vis5d recognizes wind and thermodynamic variables for further computation, the main variable names should have a standard name as 'T', 'Q', 'U', 'V', 'W'.

The variable tab2ver can be left to its default value of -1 if a unique version of table 2 is used throughout the file (this should be usually be the case).

If the vector nzlev is not provided (i.e. all its elements are 0) then the output vertical level type and values of levels (vert_args) are assumed to be the same as those for input levels and no interpolation is made.

The variable const should be set to true for fields which are constant in time, in order to avoid reading them more than once (it is automatically set to true for the model orography field).

The namelist config can contain the following vector dimensioned as numtimes:
Name Type Meaning Default
tabfth INT() forecast times to read from grib in hours 0
tabftd INT() forecast times to read from grib in days 0

If numtimes is not specified, the number of time levels is determined from the number of elements in tabfth or tabftd vectors.

If fixedfth<0, the elements of tabfth and tabftd vectors are treated as forecast times starting from the same initial date (default); if fixedfth$\geq$0 then the elements of tabfth and tabftd vectors are considered as offsets for computing the emission date from the initial date while the forecast time searched for is +fixedfth hours (mainly useful for displaying analysis data with fixedfth=0). The emission date is determined from the first valid grib field found in the input grib file.

The namelist config can contain the following vectors dimensioned as the maximum number of input and output vertical levels respectively:
Name Type Meaning Default
tablev INT() input vertical levels coordinate values to be found in grib none
vert_args REAL() values of output vertical levels (in Km if height) none


The namelist names

The namelist names, can contain the following scalar variables:
Name Type Meaning Default
inname CHAR Name of grib input file none
outname CHAR Name of vis5d output file grib input file name with suffix .vis5d

This namelist is optional; values for the file names can be given also as command-line arguments (see section 3.1) if enabled in compilation, so that the namelist is read only if inname is not given on the command line.


Mandatory variables in the namelist

A minimal namelist file should contain at least the following variables: varname, lowlev, nl, tabfth, tablev; moreover, if the fields should be interpolated on height levels, also vert_args and igo should be specified and the grib should contain the orography field (either as height or geopotential).


The input file SOUNDSTAZ.DAT

This file will be used if the variable sounding is enabled in namelist config. It describes how many files will be produced and the coordinate for vertical profiles.


 3
 SMRER
 PMPMO
 PMPVE
 1        101   45.02775       9.666667      -1.000000     Piacenza                
 1        102   44.80000       10.33333      -1.000000     Parma                   
 1        103   44.66667       10.91667      -1.000000     Modena                  
 1      16429   37.91667       12.50000       14.00000     TRAPANI/BIRGI           
 1      16560   39.25000       9.066667       5.000000     P CAGLIARI/ELMAS        
 2          1   44.65164       10.92667    
 2          3   44.54083       10.85389    
 3          1   45.45306       12.24167    
 3          2   45.49581       12.24444    
 4          1   43.60889       10.89862    
 4          2   43.60250       11.24366    
 4          3   43.73079       11.07557    
 4          4   43.72385       11.42131    
 4          5   43.85882       10.90674    
 4          6   43.85241       11.25326

  1. the first record describes how many files wil be created
  2. the second up to the Nth are the prefixes for the name of the files
  3. all remaning records describe the virtual sounding stations
  4. the first field is the ordinal number of the file in output
  5. the second is a fictitious station number
  6. third is the latitude
  7. fourth is the longitude
  8. all the following fields are optional description field like height and name


next up previous contents
Next: Optional output files Up: GRIB2V5D USER'S GUIDE Converting Previous: Running grib2v5d   Contents
Davide
2002-04-04