source: lmdz_wrf/branches/LMDZ_WRFmeas/tools/instrcutions.inf @ 1564

Last change on this file since 1564 was 414, checked in by lfita, 10 years ago

Removing WRFV3 folder and keeping only the essential

File size: 3.6 KB
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1# Whole text at `http://www.lmd.jussieu.fr/~lflmd/ASCIIobs_nc/index.html'
2
3I developed a kind of all-purpouse python tool to trasnform ASCII column-based data to netcDF.
4
5It works 'quite' easily:
6  The python script is called as:
7    python create_OBSnetcdf.py -c [Comchar] -d [DescFile] -e [Endchar] -f [obsFile] -g [debugFlag] -t [CFreftime],[CFunits] -k [obskind] -s [stloc]
8       [Comchar]: which characters (':', list) can be used as comment inside the observations file
9       [DescFile]: ASCII file with all the information of the observational data-set
10       [Endchar]: character of end of column
11       [obsFile]: observatinoal ASCII file with data in columns
12       [debugFlag]: boolean flag for debugging
13       [CFreftime],[CFunits]: reference and time-units to transform the date to CF convention
14       [obskind]: kind of observation, up to now:
15         'multi-points': multiple individual punctual obs (e.g., lightning strikes)
16            A new variale called 'obsmap' with the number of observations at a grid mesh of 100x100 will be added
17         'single-station': single station on a fixed position
18         'trajectory': following a trajectory
19            A new variale called 'obstrj' with the number of observations at a grid mesh of 100x100x100 will be
20              added
21       [stloc]: only with [obskind]='single-station', a ',' list of longitude,latitude,height will be used to
22          add new variables on the netCDF file with the given values ('lon','lat','height') or with 'st' header
23          if these variables already exist
24
25    Inside the [DescFile] you will find:
26      institution=Institution who creates the data
27      department=Department within the institution
28      scientists=names of the data producers
29      contact=contact of the data producers
30      description=description of the observations
31      acknowledgement=sentence of acknowlegement
32      comment=comment for the measurements
33
34      MissingValue='|' list of missing values (strings as they are in the ASCII file) within the data
35      comment=comments
36
37      varN='|' list of variable names
38      varLN='|' list of long variable names
39      varU='|' list units of the variables
40      varBUFR='|' list BUFR code of the variables
41      varTYPE='|' list of variable types ('D', 'F', 'I', 'I64', 'S')
42
43      NAMElon=name of the variable with the longitude (x position)
44      NAMElat=name of the variable with the latitude (y position)
45      NAMEheight=name of the variable with the heights (z position)
46      NAMEtime=name of the varibale with the time
47      FMTtime=format of the time (available: as in 'C'[%Y,...], 'CFtime' for already CF-like time)
48
49   * All the values before 'varN' are stored as global attributes
50   * All the content as 'var[N/LN/U/BUFR/TYPE]' is used to transform the data
51   * [MissingValue] is used during the transformation of data and then accordingly to the variable type the correspondant '_FillValue' is assigned
52   * NAME[lon/lat/height/time]: are used as reference for the netCFD file (in this version only 'NAMEtime')
53      [NAMEtime] is used to compute the CF-time axis. It can be a combination of different columns (see atached files), whereas [FMTtime] will be used to transform the correspondant time. (How ever, python can not deal with the 7th decimal of the microseconds, so anbything smalloer is lost during the conversion. For all the rest I think is fine). For times already in CF-compilant, FMTtime=CFtime
54
55As always is easier if you see and example (see atached). I called it in this case as:
56
57python create_OBSnetcdf.py -c '#' -d description.dat -e space -f ATDnet_data_121018.csv -t 19491201000000,seconds -k multi-stations
58
59Hope it is useful,
60
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