NAME
LATS - parameter file
DESCRIPTION
The parameter file contains information which controls the
operation of the LATS I/O library. This file is divided into
four tables: variables, vertical dimension types, centers,
and qc marks. Each table is preceded by a `#!' comment, and
consists of single-line entries separated by `|' (vertical
bar). Comments are preceded by `#' (pound sign). The tables
can appear in any order in the parameter file. For all
fields, leading and trailing whitespace characters are
ignored.
See the GRIB manual (for example,
ftp://nic.fb4.noaa.gov/pub/nws/nmc/docs/gribed1) for a more
complete description of the GRIB-related fields.
VARIABLE TABLE
The variable table defines acceptable variable names, and
information associated with each variable name. The table is
preceded by a `#!variable' comment. Each line has the form:
name | id | title | units | datatype | level_type | decimal_scale_factor | precision | comments_1 | comments_2
where
name is the variable name.
id is the GRIB parameter number.
title is the long name, or description of the vari-
able.
units is the units of the variable.
datatype is the datatype of the variable, either
`float' for floating point, or `int' for in-
teger.
level_type is the name of a single-level vertical dimen-
sion type (see below), or blank if either the
variable is multi-level or the variable has
no associated vertical dimension.
decimal_scale_factor
is the GRIB packing decimal scale factor.
Specify the value `-999' if no decimal scal-
ing is to be performed for GRIB output. If
specified, this field overrides the value of
precision. This field is ignored for netCDF
output.
precision is the GRIB packing number of bits of preci-
sion. Specify `-999' if the bit length should
be determined on a per-level basis. This
field is ignored for netCDF output, or if de-
cimal scaling is specified.
comments_1 is a comment field, ignored by LATS
comments_2 is a comment field, ignored by LATS
VERTICAL DIMENSION TYPE TABLE
The vertical dimension type table defines the categories of
vertical dimensions which may be used with LATS. The table
is preceded by a `#!vert' comment. Each line has the form:
level_type | description | units | verticality | positive | GRIB_id | GRIB_p1 | GRIB_p2 | GRIB_p3
where
level_type is the name of the vertical dimension type.
description is the description of the vertical dimension
type.
units is the units associated with the vertical di-
mension type. This field may be left blank
for single-level dimensions, if not applica-
ble.
verticality is either `single' for single-level or sur-
face dimension, or `multi' for a dimension
type which can have more than one value.
positive is `up' if increasing values of the dimension
are oriented upward in a physical sense,
`down' otherwise. For example, pressure lev-
els would have positive value `down' , since
increasing pressure levels correspond to de-
creasing height.
GRIB_id is the GRIB level type indicator (PDS octet
10), is ignored for netCDF output.
GRIB_p1 is the GRIB PDS octet 11, typically the value
at the top of a layer, ignored for netCDF
output.
GRIB_p2 is the GRIB PDS octet 12, typically the value
at the bottom of a layer, ignored for netCDF
output.
GRIB_p3 is the GRIB combined PDS octets 11, 12, typi-
cally the value for a level (non-layer). If
specified, this value overrides GRIB_p1 and
GRIB_p2. This field is ignored for netCDF
output.
CENTER TABLE
The center table associates GRIB numerical identifiers with
the modeling center. This table is only used for GRIB out-
put. The table is preceded by a `#!center' comment. Each
table entry is of the form:
center | GRIB_process | GRIB_center | GRIB_subcenter
where
center is the name of the modeling center.
GRIB_process is the GRIB generating process ID, PDS octet
6.
GRIB_center is the GRIB center ID, PDS octet 5
GRIB_subcenter is the GRIB subcenter ID, PDS octet 26
QUALITY CONTROL TABLE
The quality control table defines the values used by the
LATS quality control routine. The table is preceded by a
`#!qc' comment. Each table entry has the form:
variable | level_type | level | mean | std | tolerance | range | rangetol
where
variable is the variable name.
level_type is the type of level, as defined in the vert-
ical dimension types table, or blank if there
is no level associated with the variable.
level is the floating-point level value, or blank
if the `level_type' field is blank.
mean is the observed mean at the specified level.
std is the observed standard deviation at the
specified level.
tolerance is the number of standard deviations about
the mean. In other words, if
abs(calculated_mean - mean) > (std * toler-
ance), generate a quality control exception.
range is the observed (maximum - minimum)
rangetol is the range tolerance, i.e., if
calculated_range > (rangetol * range), gen-
erate a quality control exception.
EXAMPLE
Here is a sample, albeit rudimentary, parameter file:
# Sample LATS parameter file
#!variable
ua | 33 | u wind | m/s | float | | 1 | -999 | comment | comment |
va | 34 | v wind | m/s | float | | 1 | -999 | comment | comment |
prc | 144 | Convective precipitation rate | kg/(m^2*s) | float | sfc | 2 | -999 | comment | comment |
#!vert
plev | Pressure level | hPa | multi | down | 100 | 0 | 0 | 0
sfc | Earth surface | | single | up | 1 | 0 | 0 | 0
#!center
pcmdi | 100 | 100 | 1
#!qc
ua | plev | 1000.0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0
ua | plev | 925.0 | 6.0 | 7.0 | 8.0 | 9.0 | 10.0
va | plev | 1000.0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0
va | plev | 925.0 | 6.0 | 7.0 | 8.0 | 9.0 | 10.0
ENVIRONMENT VARIABLES
LATS_PARMS Parameter filename. If not defined, LATS
uses an internal table.
SEE ALSO
lats(3), netcdf(3)
BUGS
NOTES