[ncl-talk] How to change the data on a rectilinear lat/lon grid to a curvilinear grid whithout changing its original resolution

Dave Allured - NOAA Affiliate dave.allured at noaa.gov
Thu Aug 18 14:13:34 MDT 2016


If you only want to make a map, then do not regrid the data.  That is what
reduces the resolution.

Instead, plot the ORIGINAL data on a map, but use the WRF projection
parameters.  Start with example 1 "dataonmap_1.ncl" on this page:

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

Change to Lambert Conformal with this resource.  You will get a true
Lambert Conformal global map with only this single change:

   res at mpProjection = "LambertConformal"

You will probably want to change to WRF projection parameters using the
following resources and other related ones.  These control the view
location over the surface of the earth:

   res at mpLambertParallel1F
   res at mpLambertParallel2F
   res at mpLambertMeridianF
   res at mpLimitMode

Copy these settings from other WRF plot programs.  If they are values read
from WRF data files, you might have to get the actual values and hard code
them into the TRMM version of your plot program.

--Dave


On Thu, Aug 18, 2016 at 2:55 AM, 易路 <dg1225033 at smail.nju.edu.cn> wrote:

> Hi all,
>   I would like to plot the TRMM 3B42 precipitation data (0.25 degree) on a
> map with the "Lambert Comformal" projection, so as to keep the same
> projection with the WRF output data. But when I used the funtions like
> rgrid2rcm or esmf_regrid, the resolution of the TRMM data changed from the
> original 0.25 degree to the resolution of WRF output data.
>   So I doubt whether there is any other functions to change the TRMM data
> on a  rectilinear lat/lon grid to a curvilinear grid whithout changing its
> original resolution?
>
> Thanks a lot!
> Best regards!
>
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