NAME
copygb - copies GRIB files
SYNOPSIS
copygb [-g "grid [kgds]"] [-i "ip [ipopts]"]
[-k "kpds"] [-v "uparms"] [-X]
[-B mapgrib [-b mapindex] [-A "<> mapthreshold"] [-K
"mapkpds"]]
[-M "mask"] [-a]
then either:
grib1 index1 grib2
or:
-x grib1 grib2
DESCRIPTION
The command copygb copies all or part of one GRIB file to another
GRIB file, interpolating if necessary. Unless otherwise directed
(-x option), the GRIB index file is also used to speed the reading.
The fields are interpolated to an output grid if specified (-g
option).
The interpolation type defaults to bilinear but may be specified
directly
(-i option). The copying may be limited to specific fields (-k
option).
It may also be limited to a specified subgrid of the output grid
or to a subrange of the input fields (-B and -b, -A, and -K
options).
Fields can be identified as scalars or vectors (-v option), which
are
interpolated differently. The invalid data in the output field can
be
filled with mask values or merged with a merge field (-M and -m
options).
The output GRIB message can also be appended to a file (-a option).
If grib2 is specified as '-', then the output GRIB file is written
to standard output.
Options
-a
Appends rather than overwrites the output GRIB
file.
-A "<> mapthreshold"
Inequality and threshold used in determining
where on the map the data will be copied.
The data are copied only where the given
map field is on the correct side of the
threshold.
The mapthreshold defaults to '>-1.e30'; in this
case,
only the map field's bitmap will limit the
domain.
-b mapindex
Optional index file used to get the map field.
-B mapgrib
GRIB file used to get the map field.
The map
field
is read from the GRIB file and compared to the
map threshold to determine for which region on
the map
the data will be copied.
The mapgrib can be
the name
of an actual GRIB file (in which case the index
file may be specified with the -b option) or it
can
be '-1'.
If mapgrib is '-1', then the input
GRIB file
(first positional argument) is used.
The -K option specifies which field to read
from
the mapgrib GRIB file.
If mapgrib is an actual
file,
then the first field is taken if -K is not
specified.
On the other hand, if mapgrib is '-1', then if
the
if -K is not specified, the current field is
taken
as the map field.
A special exception is if -K
'-1'
is specified, in which case the current field
is
taken as the map field and it is applied before
any
interpolation; otherwise the map field is
always
applied after interpolation.
-g "grid [kgds]"
Output grid identification.
If grid=-1 (the
default),
then the output grid is the same as the input
grid.
If grid=-4, then the grid is that of the map
field.
If grid=-5, then the grid is that of the merge
field.
If 0<grid<255, then grid designates an NCEP
grid.
If grid=255, then the grid must be specified by
the
full set of kgds parameters determining a GRIB
GDS
(grid description section) in the W3FI63
format.
-i "ip [ipopts]"
Interpolation options. The default is bilinear
interpolation (ip=0). Other interpolation
options
are bicubic (ip=1), neighbor (ip=2), budget
(ip=3),
and spectral (ip=4).
Spectral interpolation is
forced
even if the input and output grids are the
same.
See the documentation for iplib for further
details.
-k "kpds"
Full set of kpds parameters determing a GRIB
PDS
(product definition section) in the W3FI63
format
determining the field(s) to be copied.
Note
that
kpds(5) is the parameter indicator (PDS octet
9).
A wildcard is specified by -1 (the defaults).
If "kpds" is equal to "w", then the requested
record
numbers are read in from standard input
instead,
one record per line and possibly delimited by a
colon
(so that wgrib could pipe requests to copygb).
If the -k is not specified, then copygb will
attempt
to copy every field in the input GRIB file.
-K "mapkpds"
Full set of kpds parameters determing a GRIB
PDS
(product definition section) in the W3FI63
format
determining the map field to be used to
determine
where on the map the data will be copied.
A wildcard is specified by -1 (the defaults).
-m mergeindex
Optional index file used to get the merge
field.
-M "mask"/mergegrib
Mask used to fill out bitmapped areas of the
map.
If specified, there will be no bitmap in the
output.
The mask must be in the format '#value' where
value
is the real number used to fill out the field.
Otherwise, the argument is interpreted as a
merge
GRIB file. Then for each GRIB message copied,
a merge field is found in the merge GRIB file
with the same parameter and level indicators
as the copied field. This merge field is
interpolated
to the output grid and used to fill out the
bitmapped
areas of the map, at least where the merge
field
is not bitmapped.
No merging is done if no
merge
field is found.
-N namelist
Namelist file to override default output
options.
The namelist must start with &NLCOPYGB and end
with /.
Namelist variables are:
IDS(255)
Output decimal scaling by
parameter
IBS(255)
Output binary scaling by
NBS(255)
Output number of bits by
parameter
parameter
-v "uparms"
Parameter indicator(s) for the u-component of
vectors.
The parameter indicator for the v-component is
assumed
to be one more than that of the u-component.
If the -v option is not specified, then the
wind
components (parameters 33 and 34) are the only
fields
assumed to be vector components in the GRIB
file.
-x
Turns off the use of an index file.
The index
records
are then extracted from the GRIB file, which
will increase the time taken by copygb.
-X
Turns on verbose printout. This option is
incompatible with GRIB output to standard
output.
EXAMPLES
(1) Interpolate an entire GRIB file to the 2.5 x 2.5 global grid.
day=960716
g1=/com/fnl/PROD/fnl.$day/gdas1.T00Z.PGrbF00
x1=/com/fnl/PROD/fnl.$day/gdas1.T00Z.PGrbiF00
copygb -g2 $g1 $x1 gribout1
(2) Copy precipitation using budget interpolation to the AWIPS 212
grid.
day=960716
g1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbF24
x1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbiF24
copygb -g212 -i3 -k'4*-1 61' $g1 $x1 gribout2
(3) Copy precipitation, interpolating rain and no-rain domains
separately.
day=960716
g1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbF24
x1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbiF24
copygb -g212 -i3 -k'4*-1 61' -B-1 -K-1 -A\>0 -M\#0 $g1 $x1
gribout3
(4) Copy precipitation again, but with no index file and only over
land.
day=960716
g1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbF24
copygb -xg212 -i3 -k'4*-1 61' -B-1 -K'4*-1 81' -A\>0.5 $g1
gribout4
(5) Copy momentum flux as a vector to a user-defined grid,
specifically
a 0.1 x 0.1 degree grid from 25N to 45N and from 90W to 70W.
day=960716
g1=/com/avn/PROD/avn.$day/gblav.T00Z.PGrbF24
grid='255 0 201 201 25000 270000 128 45000 290000 100 100 64'
copygb -g"$grid" -i3 -k'4*-1 124' -v124 $g1 $x1 gribout5
(6) Interpolate 250 mb height from staggered eta grid to AWIPS 212
grid.
day=960716
g1=/com/eta/PROD/meso.$day/meso.T12Z.EGRD3D09.tm00
copygb -xg212 -k'4*-1 7 100 250' $g1 gribout6
(7) Verbosely extract 500 mb height from ECMWF file.
day=960716
g1=/scom/mrf/prod/ecmwf.$day/ecmgrb25.T12Z
x1=/scom/mrf/prod/ecmwf.$day/ecmgrbi25.T12Z
copygb -X -k'4*-1,7,100,500' $g1 $x1 gribout7
(8) Use wgrib to extract 1000 and 500 mb heights to grid 2
and append output to the pre-existing file gribarch8.
day=19991005
g1=/com/fnl/prod/fnl.$day/gdas1.t00z.pgrbf00
wgrib $g1|grep :HGT:|grep -E ':1000 mb:|:500 mb:'|\
copygb -xg2 -kw -a $g1 gribarch8
(9) Use wgrib to merge two WAFS files onto grid 212.
copygb -xg212 -M wafs39 wafs40 wafs212
(10) Force vertical velocity to have a decimal scaling of 3.
day=20000119
g1=/com/eta/prod/eta.$day/eta.t12z.awip3224.tm00
echo ' &NLCOPYGB IDS(039)=3, /' >tmpnlcopygb
copygb -N tmpnlcopygb -g3 -x $g1 gribout10
rm tmpnlcopygb
AUTHOR
Mark Iredell
Global Modeling Branch
Environmental Modeling Center
National Centers for Environmental Prediction
National Weather Service
National Oceanographic and Atmospheric Administration
Department of Commerce
Man page last modified on January 19,
2000.