[gradsusr] can't open IBTraCS nc file

Marcelino II Villafuerte mqvillafuerte at gmail.com
Tue Jan 3 23:29:30 EST 2012


Dear All,

Has anyone successfully opened IBTraCS file in GrADS? I have recently found
about this typhoon data archive combining different agencies best track in
a netcdf file format, the data is downloadable in this link:
ftp://eclipse.ncdc.noaa.gov/pub/ibtracs/v03r03/wmo/netcdf/year/

However, when I tried to open it in GrADS 2.0.1, I received this error:

*ga-> sdfopen Year.1901.ibtracs_wmo.v03r03.nc
Scanning self-describing file:  Year.1901.ibtracs_wmo.v03r03.nc
gadsdf: SDF file has no discernable X coordinate.
  To open this file with GrADS, use a descriptor file with an XDEF entry.
  Documentation is at http://iges.org/grads/gadoc/SDFdescriptorfile.html*

I tried to read the documentation given above but I still can't figure out
how to make a descriptor file for the said file. ncdump gives the following
details about the file:

dimensions:
        storm = UNLIMITED ; // (16 currently)
        time = 137 ;
        ncharsn = 13 ;
        ncharnm = 55 ;
        center = 24 ;
        ncharcn = 10 ;
variables:
        char storm_sn(storm, ncharsn) ;
                storm_sn:long_name = "Storm serial number" ;
        char name(storm, ncharnm) ;
                name:long_name = "Storm name" ;
        short numObs(storm) ;
                numObs:long_name = "Number of observations for the storm" ;
        short season(storm) ;
                season:long_name = "Year based on season" ;
                season:Note = "Following WMO,\n",
                        "NH Seasons begin 1 January and \n",
                        "SH Seasons begin 1 July the prior year" ;
        byte track_type(storm) ;
                track_type:long_name = "Track type" ;
                track_type:key = "0 = main - cyclogenesis to cyclolysis\n",
                        "1 = merge - cyclogenesis to merger\n",
                        "2 = split - split to cyclolysis\n",
                        "3 = other - split to merger" ;
        byte genesis_basin(storm) ;
                genesis_basin:long_name = "Basin of genesis" ;
                genesis_basin:units = " " ;
                genesis_basin:key = "0 = NA - North Atlantic\n",
                        "1 = SA - South Atlantic\n",
                        "2 = WP - West Pacific\n",
                        "3 = EP - East Pacific\n",
                        "4 = SP - South Pacific\n",
                        "5 = NI - North Indian\n",
                        "6 = SI - South Indian\n",
                        "7 = AS - Arabian Sea\n",
                        "8 = BB - Bay of Bengal\n",
                        "9 = EA - Eastern Australia\n",
                        "10 = WA - Western Australia\n",
                        "11 = CP - Central Pacific\n",
                        "12 = CS - Carribbean Sea\n",
                        "13 = GM - Gulf of Mexico\n",
                        "14 = MM - Missing" ;
                genesis_basin:Note = "Based on where the storm began" ;
        byte num_basins(storm) ;
                num_basins:long_name = "Number of basins through which the
storm passes" ;
                num_basins:units = " " ;
        byte basin(storm, time) ;
                basin:long_name = "Basin" ;
                basin:units = " " ;
                basin:key = "0 = NA - North Atlantic\n",
                        "1 = SA - South Atlantic\n",
                        "2 = WP - West Pacific\n",
                        "3 = EP - East Pacific\n",
                        "4 = SP - South Pacific\n",
                        "5 = NI - North Indian\n",
                        "6 = SI - South Indian\n",
                        "7 = AS - Arabian Sea\n",
                        "8 = BB - Bay of Bengal\n",
                        "9 = EA - Eastern Australia\n",
                        "10 = WA - Western Australia\n",
                        "11 = CP - Central Pacific\n",
                        "12 = CS - Carribbean Sea\n",
                        "13 = GM - Gulf of Mexico\n",
                        "14 = MM - Missing" ;
                basin:Note = "Based on present location" ;
                basin:_FillValue = -127b ;
        byte wind_avg_period(center) ;
                wind_avg_period:long_name = "Wind speed averaging period" ;
                wind_avg_period:units = "min" ;
                wind_avg_period:_FillValue = -127b ;
        char source(center, ncharcn) ;
                source:long_name = "Source name" ;
                source:Note = "This order matches the dimension in source_*
variables" ;
        double time_wmo(storm, time) ;
                time_wmo:long_name = "Modified Julian Day" ;
                time_wmo:units = "days since 1858-11-17 00:00:00" ;
                time_wmo:_FillValue = 9.96921e+36 ;
        short lat_wmo(storm, time) ;
                lat_wmo:long_name = "Storm center latitude" ;
                lat_wmo:units = "degrees_north" ;
                lat_wmo:scale_factor = 0.01f ;
                lat_wmo:_FillValue = -32767s ;
        short lon_wmo(storm, time) ;
                lon_wmo:long_name = "Storm center longitude" ;
                lon_wmo:units = "degrees_east" ;
                lon_wmo:scale_factor = 0.01f ;
                lon_wmo:_FillValue = -32767s ;
        byte alt(storm, time) ;
                alt:long_name = "Altitude" ;
                alt:units = "m" ;
                alt:_FillValue = -127b ;
                alt:note = "only included in an attempt to have THREDDS
recognize the file as a trajectory" ;
        short wind_wmo(storm, time) ;
                wind_wmo:long_name = "Maximum Sustained Wind (MSW)" ;
                wind_wmo:units = "kt" ;
                wind_wmo:scale_factor = 0.1f ;
                wind_wmo:_FillValue = -32767s ;
        short pres_wmo(storm, time) ;
                pres_wmo:long_name = "Minimum Central Pressure (MCP)" ;
                pres_wmo:units = "mb" ;
                pres_wmo:scale_factor = 0.1f ;
                pres_wmo:_FillValue = -32767s ;
        byte sub_basin(storm, time) ;
                sub_basin:long_name = "Sub-Basin" ;
                sub_basin:units = " " ;
                sub_basin:key = "0 = NA - North Atlantic\n",
                        "1 = SA - South Atlantic\n",
                        "2 = WP - West Pacific\n",
                        "3 = EP - East Pacific\n",
                        "4 = SP - South Pacific\n",
                        "5 = NI - North Indian\n",
                        "6 = SI - South Indian\n",
                        "7 = AS - Arabian Sea\n",
                        "8 = BB - Bay of Bengal\n",
                        "9 = EA - Eastern Australia\n",
                        "10 = WA - Western Australia\n",
                        "11 = CP - Central Pacific\n",
                        "12 = CS - Carribbean Sea\n",
                        "13 = GM - Gulf of Mexico\n",
                        "14 = MM - Missing" ;
                sub_basin:Note = "Based on present location" ;
                sub_basin:_FillValue = -127b ;
        byte nature_wmo(storm, time) ;
                nature_wmo:long_name = "Storm nature" ;
                nature_wmo:key = "0 = TS - Tropical\n",
                        "1 = SS - Subtropical\n",
                        "2 = ET - Extratropical\n",
                        "3 = DS - Disturbance\n",
                        "4 = MX - Mix of conflicting reports\n",
                        "5 = NR - Not Reported\n",
                        "6 = MM - Missing\n",
                        "7 =  - Missing" ;
                nature_wmo:Note = "Based on classification from original
sources" ;
                nature_wmo:_FillValue = -127b ;
        byte source_wmo(storm, time) ;
                source_wmo:long_name = "Source used as WMO agency" ;
                source_wmo:flag_values = "0 1 2 3 4 5 6 7 8 9 10 11 12 13
14 15 16 17 18 19 20 21 22 23" ;
                source_wmo:flag_meanings = "hurdat_atl td9636 reunion atcf
ds824_sh ds824_ni bom ds824_au jtwc_sh jtwc_wp ds824_wp jtwc_io cma
hurdat_epa jtwc_ep ds824_ep jtwc_cp tokyo neumann hko cphc wellington
newdelhi nadi" ;
                source_wmo:_FillValue = -127b ;

// global attributes:
                :Title = "IBTrACS-WMO: NetCDF reformat" ;
                :Version = "v03r03" ;
                :Description = "IBTrACS-WMO data reformatted to contain \n",
                        "all data in one netCDF file. Also an attempt has
been made\n",
                        "to have the data appear as trajectories in the
CDM" ;
                :cdm_datatype = "Trajectory" ;
                :trajectoryDimension = "storm" ;
                :Conventions = "CF-1.0" ;
}


Sorry for the long mail. Thanks in advance for any help..

Best regards,

Mar
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