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

[易路]

Dear Dave,
 
Thanks a lot for your detail and professinal reply. Setting the resources of mpProjection,  mpLambertParallel1F, mpLambertParallel2F, mpLambertMeridianF mpLimitMode and other related resources perfectly resolved my problem. Now I can plot the TRMM data on a  map which having the same projection of WRF output data, and don't need to regrid them. Deeply appreciations for your reply!
 
Best regards!
 
Yi Lu
 
 
 






易路

南大邮件系统/学生/博士生/12级博士生

南京市汉口路22号 




 
 
 
------------------ Original ------------------
From:  "Dave Allured - NOAA Affiliate"<dave.allured at noaa.gov>;
Date:  Fri, Aug 19, 2016 04:13 AM
To:  "易路"<dg1225033 at smail.nju.edu.cn>; 
Cc:  "ncl-talk"<ncl-talk at ucar.edu>; 
Subject:  Re: [ncl-talk] How to change the data on a rectilinear lat/lon gridto a curvilinear grid whithout changing its original resolution

 
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!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20160820/21c12cc4/attachment.html