contact: Jörg Wegner
wegner @dkrz.de
tel.: +49 40 41173 178
The afterburner
transforms and selects data from T-model GRIB or netCDF files.
The actual Version is 4.14
Find some more informations and the source code on this page.
SYNOPSIS
after [ -options ] infile resultfile < namelist
DESCRIPTION
The program "after" reads, unpacks, transforms and selects data
from T-model GRIB/netCDF files, and writes them to
SERVICE/GRIB/netCDF format for further processing (i.e. plotting).
Additionally, pressure or height interpolation is optional
(refer to parameter description of "UNITSEL").
Possible combinations of TYPE, CODE and MEAN
| TYPE = 0 : | CODE = | 130 temperature | MEAN = 0 |
| 131 u-velocity | |||
| 132 v-velocity | |||
| 133 specific humidity | |||
| 138 vorticity | |||
| 148 streamfunction | |||
| 149 velocity potentia | |||
| 152 LnPs | |||
| 155 divergence | |||
| TYPE = 10: | CODE = | (same as TYPE 0) | MEAN = 0 |
| TYPE = 11: | CODE = | (same as TYPE 0) | MEAN = 0 |
| TYPE > 11: | CODE = | (all codes) | MEAN = 0/1 |
Vorticity, divergence, streamfunction and velocity potential
need special treatment in the vertical transformation.
They are not available as types 30, 40 and 41.
If you select one of these combinations, type is automatically
switched to the equivalent types 70, 60 and 61.
NAMELIST
&SELECT
TYPE = , CODE = , LEVEL = , MULTI = , MEAN = , INTERVAL = ,
TIMESEL = , UNITSEL = , FORMAT = , PRECISION =
&END
| default -> | TYPE = 0 : | Hybrid level | spectral coefficients |
| TYPE = 10 : | Hybrid | level fourier coefficients | |
| TYPE = 11 : | Hybrid | level zonal mean sections | |
| TYPE = 20 : | Hybrid | level gauss grids | |
| TYPE = 30 : | Pressure or Height | level gauss grids | |
| TYPE = 40 : | Pressure or Height | level fourier coefficients | |
| TYPE = 41 : | Pressure or Height | level zonal mean sections | |
| TYPE = 50 : | Pressure or Height | level spectral coefficients | |
| TYPE = 60 : | Pressure or Height | level fourier coefficients | |
| TYPE = 61 : | Pressure or Height | level zonal mean sections | |
| TYPE = 70 : | Pressure or Height | level gauss grids |
| default -> | CODE = | -1 : | process all detected codes |
| CODE = | 1 - 255 : | ECMWF field codes (130=Temperature, etc.) | |
| 256 - 258 : | internal | ||
| 259 : | sqrt(u*u + v*v) | ||
| 260 : | largescale + convective rain | ||
| 261 : | total top radiation | ||
| 262 : | total bottom radiation | ||
| 263 : | net heat flu | ||
| 264 : | net water flux |
| default -> | LEVEL = -1 : | process all detected levels |
| LEVEL =: | Up to NN + 1 hybrid, pressure or height levels | |
| (depending on TYPE and UNITSEL !!!) | ||
| NN depends on model type (e.g. 19, 31 or 39) | ||
| default -> | MULTI = 0 : | Process only one input file |
| MULTI = n : | Process "n" input files - each containing | |
| one month. Put only the name of the first | ||
| input file on the command line. All subsequent | ||
| files are expected to be in the same directory. | ||
| The filenames must follow the syntax | ||
| experiment_YYMM, where YY denotes the year | ||
| and MM the month. | ||
| default -> | DAYIN = 30 : | Day step for incrementing input file names |
| DAYIN = nn : | Day step is nn days | |
| Used only in conjunction with MULTI != 0. | ||
| Since ECHAM4 output files follow the | ||
| naming convention | ||
| experiment_YYMM.DD | ||
| DAYIN is the time step in days between | ||
| subsequent input files for MULTI != 0. | ||
| default -> | MEAN = 0 : | Write out all terms |
| MEAN = 1 : | Compute and write monthly or daily mean fields | |
| !!! Only for TYPE >= 20 !!! | ||
| MEAN = 2 : | Compute and write monthly or daily deviations. | |
| !!! Only for TYPE = 20 or TYPE = 30 !!! | ||
| MEAN = 3 : | Combination of MEAN=1 and MEAN=2. | |
| Each mean field is followed by a deviation | ||
| field with an identical header record. | ||
| !!! Only for TYPE = 20 or TYPE = 30 !!! | ||
| default -> | INTERVAL = 0 : | Process data on monthly intervals |
| INTERVAL = 1 : | Process data on daily intervals | |
| e.g. To compute daily averages | ||
| set MEAN = 1 and INTERVAL = 1 | ||
| INTERVAL = 2 : | Process data over all inputfiles | |
| e.g. To compute an average over | ||
| all inputfiles | ||
| set MEAN = 1 and INTERVAL = 2 | ||
| default -> | TIMESEL = -1 : | The resultfile contains the same timesteps |
| per day as the input file. | ||
| Multiple values may be specified, i.e. | ||
| TIMESEL = 0, 12, 18 | ||
| Note that only hours existing in the input | ||
| file can be specified. | ||
| (No time interpolation or average is done) | ||
| default -> | UNITSEL = 0 : | Pressure interpolation (TYPE >= 30) |
| or hybrid level output (TYPE <= 20). | ||
| Unlike before, pressure levels less than 100 Pa | ||
| can be processed (except 0 and negative values). | ||
| UNITSEL = 1 : | Height interpolation | |
| Values specified for LEVEL are interpreted | ||
| as height-meters (TYPE >= 30). | ||
| (Maximum LEVEL: 65535 m) | ||
| UNITSEL = 2 : | Height interpolation | |
| Values specified for LEVEL are interpreted | ||
| as height-kilometers (TYPE >= 30). | ||
| (Maximum LEVEL: 65 km) | ||
| default -> | FORMAT = 0 : | SERVICE |
| FORMAT = 1 : | GRIB | |
| FORMAT = 2 : | netCDF | |
| FORMAT = 3 : | EXTRA | |
| default -> | PRECISION = 0 : | use input data precision for output |
| PRECISION = 8 : | 8 bit packed output data precison | |
| PRECISION = 16 : | 16 bit packed output data precison | |
| PRECISION = 24 : | 24 bit packed output data precison | |
| PRECISION = 32 : | 32 bit floating point output data precison | |
| PRECISION = 64 : | 64 bit floating point output data precison |
EXAMPLES
To create monthly mean over all codes and hybrid levels in GRIB format, try
after Model-file GRIB-file.avg << EOF
&SELECT TYPE=20, MEAN=1, FORMAT=1 &END
EOF
To select code 129 and 130 and interpolate to presure levels
100, 250, 500, 850, 925 and 1000 hPa, try
after Model-file GRIB-file.sel << EOF
&SELECT
TYPE=70, FORMAT=1,
CODE=129,130,
LEVEL=10000, 25000, 50000, 85000, 92500, 100000
&END
EOF
To calculate u and v velocity from vorticity and divergence on model level, try
after Model-file GRIB-file.sel << EOF
&SELECT
TYPE=20, FORMAT=1,
CODE=131,132
&END
EOF