New regridding software coming soon in NCL

This is a heads up for anybody who is interested in regridding.

In the next release of NCL (V6.1.0, scheduled for mid-February 2012), we plan to incorporated the ESMF regridding software in NCL.

For more information about ESMF (Earth System Modeling Framework):

http://www.earthsystemmodeling.org/

This software will allow you to regrid to and from rectilinear, curvilinear and unstructured grids.

We are working on a page of examples, and are interested in adding more examples with different grids. If you have some data that you would like to regrid, send me an email offline and I will be happy to try it out. I will need access to the dataset you want to regrid, and, if applicable, the dataset that contains the grid you want to regrid to. Otherwise, you can simply regrid to rectilinear global grids, like 1x1 deg, 5x5 deg, etc.

--Mary

On Jan 12, 2012, at 10:22 AM, debasish@sca.uqam.ca wrote:

> Dear Igor,
> dsgrid2s requires same dimension of lat and lon. You can use "linint2"
> which interpolates from one rectilinear grid to another using bilinear
> interpolation.
>
> Please check
> http://www.ncl.ucar.edu/Document/Functions/Built-in/linint2.shtml
>
> Thanks
>
> Debasish
>
>
>> Dear NCL group,
>>
>> i am a "long time listener, first time caller" on the NCL talk group, been
>> using a lot of useful tips from all the members. Now it is the first time
>> i
>> had to go rogue from an eavesdropper to a participant, so i hope somebody
>> will have a clue how my hurdle can be tackled.
>>
>> The problem is to regrid/interpolate a variable written in a netcdf file,
>> to a specific grid/resolution. These are all 2D variables, and in order to
>> divide them or make a scatter plot with them - i need to have them on the
>> same grids and with identical dimensions.
>>
>> To make things to the point and to refer to them more easily, i have 3 .nc
>> files:
>>
>> radar_output.nc,
>> lid_l2a_output.nc and
>> reff_slice_rev.nc,
>>
>> and these are ncl_filedump outputs of these files:
>>
>> radar_output.nc:
>> dimensions:
>> one = 1
>> nx = 255
>> ny = 1
>> nz = 90
>> float CPR_Reflectivity ( nz, nx )
>> long_name : Reflectivity [94 GHz]
>> units : mm^6 m^-3
>> plot_title : Reflectivity [mm\U6\D/m\U3\D] [94 GHz]
>>
>> lid_l2a_output.nc:
>> dimensions:
>> nx = 51
>> ny = 1
>> nz = 139
>> one = 1
>> float Extinction_3 ( nz, nx )
>> long_name : Extinction_3
>> units : 1/m
>> plot_title : Extinction [1/m]
>>
>> and finally reff_slice_rev.nc
>> dimensions:
>> nz = 80
>> nx = 512
>> variables:
>> float R_eff ( nz, nx )
>> long_name : effective radius
>> units : microns
>> plot_title : R\deff\u [microns]
>>
>> It doesn't matter to which grid i eventually need to use for all of them,
>> as long as they are the same. Maybe it would be best to get them all to
>> lid_l2a_output.nc grid, as it is the lowest one.
>>
>> Basically, i need to make a scatter plot of CPR_Reflectivity /
>> Extinction_3
>> vs. R_eff, and
>> from what i understand they all need to have the same number of grid
>> points
>> on both x and z direction. I read in the variables
>>
>> fin =
>> addfile("/data/ECSIMv15/sessions/hr18_ecsimreff_up/dave_20111130182841/
>> radar_output.nc","r") ;satellite, hr18
>> reflectivity = fin->CPR_Reflectivity(:,:)
>> reflectivity=where(reflectivity.le.0,0.0001,reflectivity) ;this is
>> eliminating negative values of z
>> reflectivity=10.0*log10(reflectivity) ;converting mm6/m3 into dBz
>>
>> and from some on line examples have understood that i need to manually
>> create a new grid to which all the values in memory will be interpolated,
>> with something like this:
>>
>> xinc = 1.0 / (NX - 1)
>> yinc = 1.0 / (NZ - 1)
>> ii = fspan(0.0, 255.0, NX)
>> xo = xinc * ii
>> yo = yinc * ii
>>
>> and then finish with a simple writing of the regrided file, for example
>> the
>> radar_output.nc.
>>
>> ;*****Delete an existing netCDF file, if present*****
>> ncdf_filename = "regrided_radar.nc"
>> if(isfilepresent(ncdf_filename)) then
>> system("/bin/rm " + ncdf_filename)
>> end if
>> ;****************************************************
>>
>> fout=addfile("/data/ECSIMv15/sessions/hr18_ecsimreff_up/regrided_radar.nc
>> ","c")
>> fout->CPR_Reflectivity = fin->CPR_Reflectivity(xo|:, yo|:)
>>
>> It does not work as it is, and the error message i get is:
>>
>> fatal:Number of dimensions in parameter (0) of (dsgrid2s) is (2), (1)
>> dimensions were expected
>>
>>
>> Thank you very much if you have a look-see of my email,
>>
>> best,
>> //Igor
>>
>>
>>
>>
>>
>>
>> --
>> Dipl.-Met. Igor Stepanov
>>
>> Faculty of Electrical Engineering, Mathematics and Computer Sciences
>> Tel: +31(0)15 2789543
>> http://rse.ewi.tudelft.nl
>> skype: stepig
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>>
>
>
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Received on Thu Jan 12 16:31:11 2012