to display NARCCAP data - repost
Juan Matias Mendez Perez
matias at TROPOSFERA.ATMOSFCU.UNAM.MX
Thu Jun 12 11:14:42 EDT 2008
Sara,
Thank you very much. I'll try to construct a data descriptor file
according your suggestions.
Best regards,
Matias
El jue, 12-06-2008 a las 11:11 +0200, Rauscher Sara A escribió:
> Dear Matías,
>
> You can use a data descriptor file to read in the data file. The dump of
> the header tells you most of what you need to know (see the
> "Lambert_conformal" variable).
> Since it's a lambert conformal project use the LCC or LCCR option for pdef.
>
> *PDEF /isize jsize/ LCCR /latref lonref iref jref Struelat Ntruelat slon
> dx dy
> /PDEF /isize jsize/ LCC /latref lonref iref jref Struelat Ntruelat slon
> dx dy// /*
> pdef 134 109 lcc 47.5 -97. 67. 54. 30.00 60.00 -97. 25000.
> 25000.
>
> /isize/ The size of the native grid in the x direction: 134
> /jsize/ The size of the native grid in the y direction: 109
> /latref/ reference latitude: 45.7
> /lonref/ reference longitude (in degrees, E is positive, W is negative)
> -97.
> /iref/ i of ref point (I guessed here by cutting the number of points
> in half)
> /jref/ j of ref point
> /Struelat/ S true lat: 30
> /Ntruelat/ N true lat: 60
> /slon/ standard longitude: -97
> /dx/ grid X increment in meters: I guessed 25000 meters, I am not sure
> what the NARCAAP grid is, there should be documentation somewhere about
> that.
> /dy/ grid Y increment in meters: ""
>
>
>
> So maybe the finished DDF could look something like this:
> DSET ^uas_WRFP_2001010103.nc
> dtype netcdf
> undef 1.e+20
> pdef 134 109 lcc 47.5 -97. 67. 54. 30.00 60.00 -97. 25000.
> 25000.
> xdef 175 linear -9.61 0.2703
> ydef 78 linear 34.70 0.2703
> zdef 1 levels 1008.43
> tdef 11440 linear 00Z01JAN1961 1dy
> vars 1
> uas=>uas 0 t,y,x surface wind speed
> endvars
>
> I am sure there are some mistakes here, but you can see now how to get
> the information from the header information and then play around with
> it. Maybe someone else can refine this further. You will need to change
> xdef and xydef, I just grabbed those from another file. There is more
> information at
> http://grads.iges.org/grads/gadoc/pdef.html
>
> good luck
> sara
> > This is my netcdf file header:
> >
> > netcdf uas_WRFP_2001010103 {
> > dimensions:
> > time = UNLIMITED ; // (11440 currently)
> > yc = 109 ;
> > xc = 134 ;
> > variables:
> > char Lambert_Conformal ;
> > Lambert_Conformal:grid_mapping_name =
> > "lambert_conformal_conic" ;
> > Lambert_Conformal:standard_parallel = 30.f, 60.f ;
> > Lambert_Conformal:longitude_of_central_meridian =
> > -97.f ;
> > Lambert_Conformal:latitude_of_projection_origin =
> > 47.5f ;
> > double yc(yc) ;
> > yc:long_name = "y-coordinate in Cartesian system" ;
> > yc:standard_name = "projection_y_coordinate" ;
> > yc:axis = "Y" ;
> > yc:units = "m" ;
> > double xc(xc) ;
> > xc:long_name = "x-coordinate in Cartesian system" ;
> > xc:standard_name = "projection_x_coordinate" ;
> > xc:axis = "X" ;
> > xc:units = "m" ;
> > double lon(yc, xc) ;
> > lon:long_name = "longitude" ;
> > lon:standard_name = "longitude" ;
> > lon:units = "degrees_east" ;
> > lon:axis = "X" ;
> > double lat(yc, xc) ;
> > lat:long_name = "latitude" ;
> > lat:standard_name = "latitude" ;
> > lat:units = "degrees_north" ;
> > lat:axis = "Y" ;
> > double time(time) ;
> > time:long_name = "time" ;
> > time:standard_name = "time" ;
> > time:units = "days since 1979-09-01 00:00:0.0" ;
> > time:axis = "T" ;
> > time:calendar = "gregorian" ;
> > float uas(time, yc, xc) ;
> > uas:long_name = "Zonal Surface Wind Speed" ;
> > uas:standard_name = "eastward_wind" ;
> > uas:units = "m s-1" ;
> > uas:_FillValue = 1.e+20f ;
> > uas:missing_values = 1.e+20f ;
> > uas:coordinates = "lon lat" ;
> > uas:grid_mapping = "Lambert_Conformal" ;
> > uas:original_name = "U10 (U at 10 M) in wrfout" ;
> > uas:original_units = "m s-1" ;
> >
> > // global attributes:
> > :institution = "PNNL (Pacific Northwest National
> > Laboratory, Richland, WA, USA)" ;
> > :source = "PNNL/NCAR WRF(2006): atmosphere:WRF; sst/sea
> > ice:AMIP2; Land:Noah;; Convcetion:KF; WSM5; CAM Radiation" ;
> > :project_id = "NARCCAP" ;
> > :table_id = "Table 2" ;
> > :realization = 1 ;
> > :experiment_id = "present-day climate using NCEP/DOE
> > Reanalysis " ;
> > :contact = "L. Ruby Leung (Ruby.Leung at pnl.gov)" ;
> > :history = "Thu Jan 31 09:41:37 2008: ncrcat uas_2001.nc
> > uas_2002.nc uas_2003.nc uas_2004.nc uas_WRFP_2000010103.nc\n",
> > "Wed Jan 30 14:12:36 2008: ncrcat
> > uas_WRFP_2001a.nc uas_WRFP_2001b.nc uas_2001.nc\n",
> > "Wed Jan 30 14:12:34 2008: ncrcat
> > uas_WRFP_2001010103.nc uas_WRFP_2001020103.nc uas_WRFP_2001030103.nc
> > uas_WRFP_2001040103.nc uas_WRFP_2001050103.nc uas_WRFP_2001060103.nc
> > uas_WRFP_2001070103.nc uas_WRFP_2001080103.nc uas_WRFP_2001090103.nc
> > uas_WRFP_2001a.nc\n",
> > "subsetted from raw WRF output using
> > pullwrf_rain.f90" ;
> > :title = "PNNL model output prepared for NARCCAP
> > present-day climate using NCEP/DOE Reanalysis" ;
> > :nco_openmp_thread_number = 2 ;
> > :Conventions = "CF-1.0" ;
> >
>
> --
>
> Dr. Sara A. Rauscher
> Earth System Physics Section
> The Abdus Salam International Centre for Theoretical Physics
> Strada Costiera 11
> 34014 Trieste ITALY
> ph: +39 040 2240 225 fax: +39 040 2240 449
> email: srausche at ictp.it
>
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