Re: linint2_Wrap Regriding

Hi Adam,

I got a problem with the regridding using linint2_Wrap(it was working for
the daily data) with a monthly data,
the is an error showed:
fatal:Dimension sizes of left hand side and right hand side of assignment
do not match.
I ncdump -c the data file:
netcdf Global_Precipitation_CRU21_30min_mT1980 {
dimensions:
latitude = 360 ;
longitude = 720 ;
bnds = 2 ;
time = UNLIMITED ; // (12 currently)
variables:
double latitude(latitude) ;
latitude:long_name = "Latitude" ;
latitude:standard_name = "latitude_north" ;
latitude:units = "degrees_north" ;
latitude:valid_range = -90., 90. ;
latitude:actual_range = -90., 90. ;
latitude:bounds = "longitude_bnds" ;
latitude:axis = "y" ;
double longitude(longitude) ;
longitude:long_name = "Longitude" ;
longitude:standard_name = "longitude_east" ;
longitude:units = "degrees_east" ;
longitude:valid_range = -180., 180. ;
longitude:actual_range = -180., 180. ;
longitude:axis = "x" ;
double latitude_bnds(latitude, bnds) ;
double longitude_bnds(longitude, bnds) ;
int time(time) ;
time:long_name = "Time" ;
time:standard_name = "time" ;
time:units = "months since 1980-01-01 00:00" ;
time:axis = "t" ;
time:actual_range = 0, 11 ;
double minimum(time) ;
double maximum(time) ;
double average(time) ;
double stddev(time) ;
float precipitation(time, latitude, longitude) ;
precipitation:long_name = "Glo_CRU21_Precipitation_mTS1980_30min" ;
precipitation:standard_name = "Precipitation" ;
precipitation:var_desc = "Precipitation" ;
precipitation:missing_value = -999.f ;
precipitation:_FillValue = -999.f ;
precipitation:scale_factor = 1.f ;
precipitation:add_offset = 0.f ;
precipitation:actual_range = 0.f, 1832.9f ;

// global attributes:
:Conventions = "CF-1.2" ;
:title = "Glo_CRU21_Precipitation_mTS1980_30min" ;
:data_type = "continuous" ;
:domain = "Global" ;
:subject = "precipitation" ;
:references = ;
:institution = ;
:source = ;
:comments = ;
data:

 latitude = -89.75, -89.25, -88.75, -88.25, -87.75, -87.25, -86.75, -86.25,
    -85.75, -85.25, -84.75, -84.25, -83.75, -83.25, -82.75, -82.25, -81.75,
    -81.25, -80.75, -80.25, -79.75, -79.25, -78.75, -78.25, -77.75, -77.25,
    ......................
    77.25, 77.75, 78.25, 78.75, 79.25, 79.75, 80.25, 80.75, 81.25, 81.75,
    82.25, 82.75, 83.25, 83.75, 84.25, 84.75, 85.25, 85.75, 86.25, 86.75,
    87.25, 87.75, 88.25, 88.75, 89.25, 89.75 ;

 longitude = -179.75, -179.25, -178.75, -178.25, -177.75, -177.25, -176.75,
    -176.25, -175.75, -175.25, -174.75, -174.25, -173.75, -173.25, -172.75,
    ..........................
    168.75, 169.25, 169.75, 170.25, 170.75, 171.25, 171.75, 172.25, 172.75,
    173.25, 173.75, 174.25, 174.75, 175.25, 175.75, 176.25, 176.75, 177.25,
    177.75, 178.25, 178.75, 179.25, 179.75 ;

 time = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ;
}
 the longitude and latitude is increasing monotonically
and I used the following code to do the regridding:

cru1990=addfile(idCRU+"Global_Precipitation_CRU21_30min_mT1980.nc","r");

V=cru1990->precipitation(:,:,:)

newlon = fspan(-84.025,-64.875,384)

newlat = fspan(34.875,50.125,306)

;************************************************

; interpolate to new grid use linint2_Wrap function

;***********************************************

V=linint2_Wrap(V&longitude,V&latitude,V,True,newlon,newlat,0)

and there was an error:
fatal:Dimension sizes of left hand side and right hand side of assignment
do not match.

Could anyone can help me on this?(Please let me know if there is a place to
upload my sample file).

Looking forward to hearing from you.

Regards,

Ping
On Thu, May 17, 2012 at 12:45 PM, Adam Phillips <asphilli@ucar.edu> wrote:

> Hi Ping,
> I think you are on the right track, but you do not need to subset the
> input array. (I am guessing that you are getting null values around the
> perimeter of your new grid.) When it comes to regridding one needs to make
> sure that the input latitudes and longitudes and the output latitudes and
> longitudes are in the same range, and flow in the same direction. You
> state you want your grid on negative longitudes, which is fine, but that
> means your input longitudes need to span the same range as well. So, I
> would recommend reading in the input data in its' entirety, flipping the
> latitudes, then use lonFlip to convert the longitudes from 0:360 to
> -180:180:
>
> pres=in->pres(:,::-1,:) ; ::-1 = flip latitudes
> pres = lonFlip(pres)
> printVarSummary(pres) ; lats should run from S->N, and lons from -180:180
>
> newlon = fspan(-84.025,-64.875,383)
> newlat = fspan(34.875,50.125,305)
> newlat@units = "degrees_north"
> newlon@units = "degrees_east"
> newsst=linint2_Wrap(pres&lon,pres&lat,pres,True,newlon,newlat,0)
>
> That should be it. If that doesn't work or if you have further questions
> please respond to ncl-talk.
> Best regards,
> Adam
>
>
> > Dear NCL user,
> >
> > I am doing interpolation from the PSD data(daily T62 Gaussian grid
> > (192x94)
> > 88.542N - 88.542S, 0E - 358.125E) to a 3 minute*3minute lon/lat regular
> > grid, I have encountered an issue with the bilinear interpolation with
> the
> > linint2_Wrap function (Interpolates from a rectilinear grid to another
> > rectilinear grid using bilinear interpolation, and retains metadata)with
> > NCL, because I've got invalid values(some of of the value are null). I
> > used
> > this code (I used a NCEP/NCAR reanalysis data, which is available by this
> > link
> >
> ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/surface_gauss/pres.sfc.gauss.2006.nc
> )
> > :
> >
> > ;*************************************************
> > ; interpolation.ncl
> > ;
> > ; Concepts illustrated:
> > ; - Interpolating from one grid to another using bilinear interpolation
> > ; use linint2_Wrap function for the retrieving all the metadata
> > ;create a new file to include the interpolated variable
> > ;
> > ;************************************************
> > load "/usr/local/lib/ncarg/nclscripts/csm/contributed.ncl"
> > ;load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> > ;change $NCARG_ROOT to /usr/local directly.
> > ;************************************************
> > begin
> > ;open file to write variable to(a new netCDF file)
> > out=addfile("pres.sfc.gauss.2006.interpolated.nc","c")
> > ;************************************************
> > ; read in netCDF file
> > ;************************************************
> > in = addfile("pres.sfc.gauss.2006.nc","r")
> > ;************************************************
> > ; read in pres
> > ;***********************************************
> > ;Use a subscript for change the dimension of pressure and also subset the
> > variable
> > pres=in->pres(time|:,{lat|34.875:50.125},{lon|95.975:115.125})
> > ;so the newPres is with the latitude increasing
> > ;***********************************************************
> > ;newlon = fspan(-84.025,-64.875,383)
> > newlon = fspan(95.975,115.125,383);convert to a (0,360) instead of
> > (-180,+180)
> > newlat = fspan(34.875,50.125,305)
> > newlat@units = "degrees_north"
> > newlon@units = "degrees_east"
> > ;************************************************
> > ; interpolate to new grid use linint2_Wrap function
> > ;***********************************************
> > newsst=linint2_Wrap(pres&lon,pres&lat,pres,True,newlon,newlat,0)
> > ;*************output variable to new file****************
> > out->pres=newsst
> > end
> >
> > Actually I need the domain range is from lon(-84.025,-64.875,383),
> > lat(34.875,50.125,305) in the lon/lat regular grid, Can I ask you what
> > will
> > be the correct range in the Gaussian grid lon 95.975:115.125? I tried
> > several times, it seems that I am confused by the translation,
> >
> > Am I use the right function for this interpolation? I will be appreciated
> > if you can point out where is the problem ?
> >
> > Best Regards,
> >
> > Ping
> >
> > --
> > Ping Yang, Ph.D.
> > CUNY Environmental Crossroads Initiative
> > Marshak Science Building - Suite 925
> > The City College of New York - CUNY
> > 160 Convent Avenue, New York NY 10031
> > Phone: 212-650-5769
> > Fax: 212-650-7064
> > _______________________________________________
> > ncl-talk mailing list
> > List instructions, subscriber options, unsubscribe:
> > http://mailman.ucar.edu/mailman/listinfo/ncl-talk
> >
>
>
> __________________________________________________
> Adam Phillips asphilli@ucar.edu
> NCAR/Climate and Global Dynamics Division
> P.O. Box 3000 (303) 497-1726
> Boulder, CO 80307-3000
> http://www.cgd.ucar.edu/cas/asphilli
>
>

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Received on Mon Aug 13 21:28:19 2012