Re: lat and lon information setting in Lambert Conformal Native Grid

From: Mary Haley (haley AT ucar.edu)
Date: Thu Jul 28 2005 - 15:25:43 MDT

  • Next message: Dennis Shea: "Re: lat and lon information setting in Lambert Conformal Native Grid"

    On Jul 28, 2005, at 2:59 PM, MUHTARJAN osman wrote:

    > Hello,
    > I am wondering how to set dimension information for a seconadry
    > variable in Lambert Conformal Native Grid . My program is like this:
    > ......
    >
    > gridx_221 = 277
    > gridy_221 = 349
    >
    > diri="/remote/beautemps/raid1/users/mjosman/NARR/NC/"
    >
    > f=addfile(diri+"narrmon-a_221_20031001.nc","r")
    > LAT2d = f->gridlat_221
    > LON2d = f->gridlon_221
    >
    > lon2d=LON2d(gridy_221|:,gridx_221|:)
    > lat2d=LAT2d(gridy_221|:,gridx_221|:)
    >
    > P=f->PRMSL_221_MSL_113
    > p = P(gridy_221|:,gridx_221|:)
    > delete(P)
    >
    > Q=f->PRATE_221_SFC_113
    > q = Q(gridy_221|:,gridx_221|:)
    > delete(Q)
    >
    > ccr = escorc(p(50,100),q) ;***1-pt correlation***
    >
    >
    > Now, if I want to plot "ccr", how should I set the lat and lon
    > information so that it can be plotted properly. I tried something like
    > this, but it failed:
    >
    > ccr!0="lat"
    > ccr@lat=lat2d
    > ccr!1="lon"
    > ccr@lon=lon2d
    >

    Hi Muhtarjan,

    I think what you want, instead of the above four lines, is the
    following:

       ccr@lat2d = lat2d
       ccr@lon2d = lon2d

    > I aslo have these settings before plotting:
    >
    > res@mpLimitMode = "Corners" ; choose range of map
    > res@mpLeftCornerLatF = lat2d@corners(0)
    > res@mpLeftCornerLonF = lon2d@corners(0)
    > res@mpRightCornerLatF = lat2d@corners(2)
    > res@mpRightCornerLonF = lon2d@corners(2)
    > res@mpProjection = "LambertConformal"
    > res@mpLambertParallel1F = lat2d@Latin1 ; ncl adds from grib file
    > res@mpLambertParallel2F = lat2d@Latin2 ; ncl adds from grib file
    > res@mpLambertMeridianF = lat2d@Lov ; ncl adds from grib file
    > res@pmTickMarkDisplayMode = "Always"
    >
    >
    > But when I run it, the program complains there's no lat/lon
    > information for plotting. And there are also warning messages like:
    >
    > warning:mpProjection is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpLimitMode is not a valid resource in slpMA_prcp_NARR_contour
    > at this time

    You didn't mention which plotting routine you are calling, but these
    errors look like you are calling a non-map routine, like
    gsn_csm_contour.
    This would cause you to get error messages about your map resources not
    being valid. You probably want to call something like
    gsn_csm_contour_map.

    Also, it is important to note that if your data is native to a lambert
    conformal projection, you should also set:

         res@tfDoNDCOverlay = True

    This tells NCL to *not* apply a transformation to the data to get it
    into a lambert conformal projection, since
    with native grids, the transformation has already been applied. You
    can go to:

         http://www.ncl.ucar.edu/Applications/lcnative.shtml

    to see some examples of generating contours on a lambert conformal
    projection. This page also talks
    a bit about native grids.

    --Mary

    > warning:mpLeftCornerLonF is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpRightCornerLonF is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpLeftCornerLatF is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpRightCornerLatF is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpLambertMeridianF is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpLambertParallel1F is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    > warning:mpLambertParallel2F is not a valid resource in
    > slpMA_prcp_NARR_contour at this time
    >
    >
    > By the way, the information of my data file is following:
    >
    > ~>ncdump -h narrmon-a_221_20031001.nc
    >
    > netcdf narrmon-a_221_20031001 {
    > dimensions:
    > gridx_221 = 277 ;
    > gridy_221 = 349 ;
    >
    > variables:
    > float gridlon_221(gridx_221, gridy_221) ;
    > gridlon_221:corners = -145.5f, -68.320045f,
    > -2.5698934f, 148.64182f ;
    > gridlon_221:GridType = "Lambert Conformal Secant or
    > Tangent, Conical or bipolar" ;
    > gridlon_221:units = "degrees_east" ;
    > gridlon_221:Latin2 = 50.f ;
    > gridlon_221:Latin1 = 50.f ;
    > gridlon_221:Dy = 32463.f ;
    > gridlon_221:Dx = 32463.f ;
    > gridlon_221:Lov = -107.f ;
    > gridlon_221:Lo1 = -145.5f ;
    > gridlon_221:La1 = 1.f ;
    > float gridlat_221(gridx_221, gridy_221) ;
    > gridlat_221:corners = 1.0000008f, 0.89794505f,
    > 46.354397f, 46.634327f ;
    > gridlat_221:GridType = "Lambert Conformal Secant or
    > Tangent, Conical or bipolar" ;
    > gridlat_221:units = "degrees_north" ;
    > gridlat_221:Latin2 = 50.f ;
    > gridlat_221:Latin1 = 50.f ;
    > gridlat_221:Dy = 32463.f ;
    > gridlat_221:Dx = 32463.f ;
    > gridlat_221:Lov = -107.f ;
    > gridlat_221:Lo1 = -145.5f ;
    > gridlat_221:La1 = 1.f ;
    > float PRATE_221_SFC_113(gridx_221, gridy_221) ;
    > PRATE_221_SFC_113:sub_center = "The North American
    > Regional Reanalysis (NARR) Project" ;
    > PRATE_221_SFC_113:center = "US National Weather Service
    > - NCEP (WMC)" ;
    > PRATE_221_SFC_113:long_name = "Precipitation rate" ;
    > PRATE_221_SFC_113:units = "kg/m^2/s" ;
    > PRATE_221_SFC_113:_FillValue = -999.f ;
    > PRATE_221_SFC_113:coordinates = "gridlat_221
    > gridlon_221" ;
    > PRATE_221_SFC_113:level_indicator = 1 ;
    > PRATE_221_SFC_113:grid_number = 221 ;
    > PRATE_221_SFC_113:parameter_number = 59 ;
    > PRATE_221_SFC_113:model = "North American Regional
    > Reanalysis (NARR)" ;
    > PRATE_221_SFC_113:forecast_time = 0 ;
    > PRATE_221_SFC_113:initial_time = "10/01/2003 (00:00)" ;
    > float PRMSL_221_MSL_113(gridx_221, gridy_221) ;
    > PRMSL_221_MSL_113:sub_center = "The North American
    > Regional Reanalysis (NARR) Project" ;
    > PRMSL_221_MSL_113:center = "US National Weather Service
    > - NCEP (WMC)" ;
    > PRMSL_221_MSL_113:long_name = "Pressure reduced to MSL"
    > ;
    > PRMSL_221_MSL_113:units = "Pa" ;
    > PRMSL_221_MSL_113:_FillValue = -999.f ;
    > PRMSL_221_MSL_113:coordinates = "gridlat_221
    > gridlon_221" ;
    > PRMSL_221_MSL_113:level_indicator = 102 ;
    > PRMSL_221_MSL_113:grid_number = 221 ;
    > PRMSL_221_MSL_113:parameter_number = 2 ;
    > PRMSL_221_MSL_113:model = "North American Regional
    > Reanalysis (NARR)" ;
    > PRMSL_221_MSL_113:forecast_time = 0 ;
    > PRMSL_221_MSL_113:initial_time = "10/01/2003 (00:00)" ;
    > }
    >
    >
    > Thank you.
    >
    > Regards,
    >
    > Muhtarjan Osman
    > ASGG
    > LAWR
    > UC Davis
    >
    >
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    > ncl-talk mailing list
    > ncl-talk@ucar.edu
    > http://mailman.ucar.edu/mailman/listinfo/ncl-talk

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