Re: linint2_Wrap Regriding

    TIME = f->time
    yyyymm = cd_calendar(time, -1)
    tStrt = ind(yyyymm.eq.200101)
    tLast = ind(yyyymm.eq.201012)

    x = f->X(iStrt:iLast,:,:,:) ; X(iStrt:iLast,:,:)

On 5/24/12 11:31 AM, Ping Yang wrote:
> Dear Adam,
>
> I have one more question, how can I extract a time period (e.g. 2001
> January to 2010 December) using NCL, I looked at a
> function calendar_decode2 which can transfer numeric time to calendar
> time, actually what I need to do is a opposite way(from calendar to
> numeric, so I can extract the time in the same script that I used for
> last discussion).
>
> Could you please give me some hints or Is here someone have the same
> experience?
>
> Best Regards,
>
> Ping
>
> On Fri, May 18, 2012 at 1:06 PM, Adam Phillips <asphilli@ucar.edu
> <mailto:asphilli@ucar.edu>> wrote:
>
> Hi Ping,
> I would think that you want the high resolution T and PSL fields
> to look like the low-resolution T and PS fields, right?
> linint2_Wrap is basically a simple linear interpolation routine,
> fine for many applications. The T and PSL T62 fields are likely
> relatively smooth, while I am guessing the T62 solar radiation
> field is not. The resulting interpolated high resolution output
> will thus likely have smoother T and PSL fields, and noisier
> solar radiation fields.
>
> Speaking to a regridding expert here, there are other
> interpolation methods that you can use, such as bi-cubic sphere
> interpolation. However, if you start out with a relatively
> smoothed field as your T62 PSL/T fields are, it's not going to
> matter whether you use a linear interpolation or a bi-cubic
> sphere interpolation routine, the results will look quite similar.
>
> Hope that helps.. Adam
>
>
> On 05/18/2012 10:02 AM, Ping Yang wrote:
>> Dear Adam,
>>
>> Thank you for the advice. Previously I was thinking to subset
>> before the interpolation which can save some computation for
>> area that not interested. It is working now.
>>
>> One more question, the interpolation function linint2_Wrap
>> seems work better with some variables like solar radiation but
>> not good for air temperature and pressure, because I found
>> that when I interpolated the air temperature and surface
>> pressure, the interpolated result is the same as the original
>> file just the region has been extracted, I think it is
>> supposed to be more intervals(which is higher resolution). but
>> for solar radiation it worked good.
>>
>> Do you (or some user here) have the same problem?
>>
>> Looking forward to hearing from you.
>>
>> Regards,
>>
>> Ping
>>
>> On Thu, May 17, 2012 at 12:45 PM, Adam Phillips
>> <asphilli@ucar.edu <mailto: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
>> <http://pres.sfc.gauss.2006.interpolated.nc>","c")
>> > ;************************************************
>> > ; read in netCDF file
>> > ;************************************************
>> > in = addfile("pres.sfc.gauss.2006.nc
>> <http://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 <tel:212-650-5769>
>> > Fax: 212-650-7064 <tel: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 <mailto:asphilli@ucar.edu>
>> NCAR/Climate and Global Dynamics Division
>> P.O. Box 3000 (303) 497-1726 <tel:%28303%29%20497-1726>
>> Boulder, CO 80307-3000
>> http://www.cgd.ucar.edu/cas/asphilli
>>
>>
>>
>>
>> --
>> 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 <tel: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 Phillipsasphilli@ucar.edu <mailto:asphilli@ucar.edu>
> NCAR/Climate and Global Dynamics Division(303) 497-1726 <tel:%28303%29%20497-1726>
> P.O. Box 3000
> Boulder, CO 80307-3000http://www.cgd.ucar.edu/cas/asphilli
>
>
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
>
>
>
> --
> 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 <tel:212-650-5769>
> Fax: 212-650-7064
>
> --
> 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
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Received on Thu May 24 16:23:17 2012