Tom Roche Wed, 21 Nov 2012 23:30:42 -0500
>>>> I'm trying to select the appropriate method(s) for regridding gas
>>>> concentrations from a global 3D grid (coordinates=longitude,
>>>> latitude, sigma) to a regional 3D grid (coordinates=col, row,
>>>> sigma) on a Lambert Conformal Conic (LCC) projection over North
>>>> America with 12-km horizontal resolution.
>>>> I suspect my difficulty is at least in part due to my uncertainty
>>>> regarding definitions of some terms as used in the NCL docs. (It
>>>> may also be due to my being totally confused :-) My global input
>>>> grid is pretty clearly spherical and curvilinear (no?)
Dennis Shea Sat, 24 Nov 2012 16:27:09 -0700
> Logically rectilinear. Any grid that can be described by a
> coordinate variable which, by definition, is a one dimensional
> monotonically {in/de}creasing numeric array [eg: lat(lat) , lon(lon) ]
> is a rectilinear array.
OK, that seems reasonable. But ...
>>>> I'm [even] less certain about the terms to use regarding my regional
>>>> output grid: Does NCL consider a 3D LCC grid "Cartesian"? [...] If
>>>> not Cartesian, I'm assuming a 3D LCC grid is at least considered
>>>> rectilinear. If a 3D LCC grid is *not* considered rectilinear, I am
>>>> very confused, and would appreciate an explanation.
Dennis Shea Fri, 23 Nov 2012 08:47:30 -0700
>>> [1] The LCC is curvilinear in NCL parlance.
Tom Roche Sat, 24 Nov 2012 12:08:38 -0500
>> I am very confused--this is the opposite of what I assumed.
> In NCL parlance, any grid where grid points are uniquely described
> by two dimensional arrays, eg, LAT(ny,ny) and LON(ny,nx) is called
> curvilinear.
But the LCC grids I'm working with are logically rectilinear, using your
description above: each coordinate variable is one-dimensional and
monotonic. Am I missing something?
>> Is LCC at least "Cartesian"? That matters to me, because I'd like to
>> do the 3D regridding with ESMF_regrid
> Once the weight file is generated,
> NCL's ESMF regridding operations will regrid any dimensional grid
but the link you cite says
http://www.ncl.ucar.edu/Document/Functions/ESMF/ESMF_regrid_with_weights.shtml
>>>>> Using the provided weight file, regrids data from one lat/lon grid
>>>>> to another.
I need to 3D-regrid from lon-lat to LCC.
TIA, Tom Roche <Tom_Roche@pobox.com>
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Received on Sun Nov 25 22:52:16 2012
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