## afterburner.txt

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NAME |
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after - transforms and selects data from T-model GRIB or netCDF files |

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SYNOPSIS |

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after [ -options ] infiles resultfile < namelist |

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DESCRIPTION |

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The program "after" reads, unpacks, transforms and selects data |

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from T-model GRIB/netCDF files, and writes them to |

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SERVICE/GRIB/netCDF format for further processing (i.e. plotting). |

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Additionally, pressure or height interpolation is optional |

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(refer to parameter description of "UNITSEL"). |

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Possible combinations of TYPE, CODE and MEAN |

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TYPE = 0 : CODE = 130 temperature MEAN = 0 |

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131 u-velocity |

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132 v-velocity |

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133 specific humidity |

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138 vorticity |

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148 streamfunction |

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149 velocity potential |

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152 LnPs |

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155 divergence |

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TYPE = 10: CODE = (same as TYPE 0) MEAN = 0 |

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TYPE = 11: CODE = (same as TYPE 0) MEAN = 0 |

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TYPE > 11: CODE = (all codes) MEAN = 0/1 |

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Vorticity, divergence, streamfunction and velocity potential |

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need special treatment in the vertical transformation. |

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They are not available as types 30, 40 and 41. |

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If you select one of these combinations, type is automatically |

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switched to the equivalent types 70, 60 and 61. The type of all |

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other variables will be switched too, because the type is a |

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global parameter. |

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OPTIONS |

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-P <nthreads> : Set number of OpenMP threads |

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-c : Print available codes and names |

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-d : Debug mode |

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NAMELIST |

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&SELECT |

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TYPE = , CODE = , LEVEL = , MULTI = , MEAN = , INTERVAL = , |

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TIMESEL = , UNITSEL = , FORMAT = , PRECISION = , SZIP = |

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&END |

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default -> TYPE = 0 : Hybrid level spectral coefficients |

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TYPE = 10 : Hybrid level fourier coefficients |

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TYPE = 11 : Hybrid level zonal mean sections |

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TYPE = 20 : Hybrid level gauss grids |

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TYPE = 30 : Pressure or Height level gauss grids |

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TYPE = 40 : Pressure or Height level fourier coefficients |

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TYPE = 41 : Pressure or Height level zonal mean sections |

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TYPE = 50 : Pressure or Height level spectral coefficients |

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TYPE = 60 : Pressure or Height level fourier coefficients |

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TYPE = 61 : Pressure or Height level zonal mean sections |

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TYPE = 70 : Pressure or Height level gauss grids |

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default -> CODE = -1 : process all detected codes |

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CODE = 1 - 255 ECMWF field codes (130=Temperature, etc.) |

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256 - 258 : internal |

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259 : sqrt(u*u + v*v) |

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260 : largescale + convective rain |

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261 : total top radiation |

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262 : total bottom radiation |

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263 : net heat flux |

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264 : net water flux |

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default -> LEVEL = -1 : process all detected levels |

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LEVEL =: Up to NN + 1 hybrid, pressure or height levels |

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(depending on TYPE and UNITSEL !!!) |

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NN depends on model type (e.g. 19, 31 or 39) |

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default -> MULTI = 0 : Process only one input file |

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MULTI = n : Process "n" input files - each containing |

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one month. Put only the name of the first |

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input file on the command line. All subsequent |

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files are expected to be in the same directory. |

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The filenames must follow the syntax |

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experiment_YYMM, where YY denotes the year |

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and MM the month. |

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default -> DAYIN = 30 : Day step for incrementing input file names |

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DAYIN = nn : Day step is nn days |

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Used only in conjunction with MULTI != 0. |

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Since ECHAM4 output files follow the |

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naming convention |

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experiment_YYMM.DD |

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DAYIN is the time step in days between |

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subsequent input files for MULTI != 0. |

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default -> MEAN = 0 : Write out all terms |

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MEAN = 1 : Compute and write monthly or daily mean fields |

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!!! Only for TYPE >= 20 !!! |

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MEAN = 2 : Compute and write monthly or daily deviations. |

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!!! Only for TYPE = 20 or TYPE = 30 !!! |

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MEAN = 3 : Combination of MEAN=1 and MEAN=2. |

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Each mean field is followed by a deviation |

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field with an identical header record. |

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!!! Only for TYPE = 20 or TYPE = 30 !!! |

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default -> INTERVAL = 0 : Process data on monthly intervals |

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INTERVAL = 1 : Process data on daily intervals |

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e.g. To compute daily averages |

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set MEAN = 1 and INTERVAL = 1 |

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INTERVAL = 2 : Process data over all inputfiles |

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e.g. To compute an average over |

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all inputfiles |

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set MEAN = 1 and INTERVAL = 2 |

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default ->TIMESEL = -1 : The resultfile contains the same timesteps |

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per day as the input file. |

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Multiple values may be specified, i.e. |

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TIMESEL = 0, 12, 18 |

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Note that only hours existing in the input |

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file can be specified. |

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(No time interpolation or average is done) |

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default ->UNITSEL = 0 : Pressure interpolation (TYPE >= 30) |

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or hybrid level output (TYPE <= 20). |

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Unlike before, pressure levels less than 100 Pa |

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can be processed (except 0 and negative values). |

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UNITSEL = 1 : Height interpolation |

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Values specified for LEVEL are interpreted |

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as height-meters (TYPE >= 30). |

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(Maximum LEVEL: 65535 m) |

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UNITSEL = 2 : Height interpolation |

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Values specified for LEVEL are interpreted |

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as height-kilometers (TYPE >= 30). |

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(Maximum LEVEL: 65 km) |

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default -> FORMAT = 0 : SERVICE |

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FORMAT = 1 : GRIB |

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FORMAT = 2 : netCDF |

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FORMAT = 3 : EXTRA |

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FORMAT = 4 : netCDF version 2 |

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FORMAT = 6 : netCDF version 4 |

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default -> PRECISION = 0 : use input data precision for output |

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PRECISION = 8 : 8 bit packed output data precision |

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PRECISION = 16 : 16 bit packed output data precision |

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PRECISION = 24 : 24 bit packed output data precision |

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PRECISION = 32 : 32 bit floating point output data precision |

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PRECISION = 64 : 64 bit floating point output data precision |

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default -> SZIP = 0 : No SZIP compression of GRIB records |

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SZIP = 1 : SZIP compression of GRIB records |

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EXTRAPOLATE = 0 : No extrapolation of missing values during the |

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interpolation from model to pressure or height level |

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(only available with MEAN = 0 and TYPE = 30) |

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default -> EXTRAPOLATE = 1 : Extrapolate missing values |

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EXAMPLES |

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To create monthly mean over all codes and hybrid levels in GRIB |

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format, try |

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after Model-file GRIB-file.avg << EOF |

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&SELECT TYPE=20, MEAN=1, FORMAT=1 &END |

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EOF |

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To select code 129 and 130 and interpolate to pressure levels |

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100, 250, 500, 850, 925 and 1000 hPa, try |

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after Model-file GRIB-file.sel << EOF |

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&SELECT |

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TYPE=70, FORMAT=1, |

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CODE=129,130, |

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LEVEL=10000, 25000, 50000, 85000, 92500, 100000 |

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&END |

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EOF |

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To calculate u and v velocity from vorticity and divergence |

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on model level, try |

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after Model-file GRIB-file.sel << EOF |

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&SELECT |

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TYPE=20, FORMAT=1, |

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CODE=131,132 |

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&END |

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EOF |

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