[ncl-talk] wrf_user_intrp3d with rectilinear grid, dimension mismatch
Ryan Connelly
rconne01 at gmail.com
Mon May 16 16:14:05 MDT 2016
Hi Mary,
After getting side-tracked for a while, I finally came back to this and
have it working as expected. Thank you for all your help!
Ryan
On Wed, Apr 27, 2016 at 3:32 PM, Mary Haley <haley at ucar.edu> wrote:
> Ryan,
>
> You have valid complaints about the ESMF_WRF_to_rect.ncl script, which
> I've tried to address. I cleaned it up so that nlat and nlon are now
> defined, and I also added some code to draw the original WRF lat/lon grid
> and the new lat/lon grid so you can better see what's happening.
>
> I've attached the code which I ran with one of my WRF files, and included
> the two images.
>
> I see that Dennis has addressed your grad_latlon_cfd question.
>
> --Mary
>
>
> On Wed, Apr 27, 2016 at 9:37 AM, Ryan Connelly <rconne01 at gmail.com> wrote:
>
>> Hi Mary,
>>
>> Thanks for taking the time to explain the differences.
>>
>> I'm trying to follow this example script:
>> https://www.ncl.ucar.edu/Applications/Templates/ESMF_WRF_to_rect.ncl.
>> This is where I got fspan from, not that I knew why I was using it. It's a
>> bit frustrating that in this script, nlat and nlon aren't actually
>> declared, and except for suggestions on what to change, the script is
>> rather sparsely commented, leaving me to guess what to input.
>>
>> Moving wrf_user_intrp3d up ahead of the grid conversion, and with
>> switching back to the 1D nlat and mlon in fspan, has gotten that portion to
>> complete successfully, so I'll call that success.
>>
>> Next problem: I'm getting an out of bounds error when I call
>> grad_latlon_cfd that doesn't make sense, since I'm feeding it that
>> [281,353] grid as the first arg and 281 and 353 as the second and third
>> args, respectively, but it says something about an error on lon (the third
>> arg).
>>
>> Thanks,
>> Ryan
>>
>> On Tue, Apr 26, 2016 at 10:15 PM, Mary Haley <haley at ucar.edu> wrote:
>>
>>> Ryan,
>>>
>>> When you use ESMF_regrid, it's not required that the dimensions of the
>>> source and destination grids match.
>>>
>>> There are three types of grids you might encounter in regridding:
>>>
>>> 1) rectilinear
>>>
>>> You have a 2D data array dimensioned nlat x nlon, and the latitudes are
>>> represented by a 1D array of size nlat, and the longitudes are represented
>>> by a 1D array of size nlon. These are often known as coordinate arrays, and
>>> you can identify them right away in NCL because when you do a
>>> "printVarSummary" on a variable, you will see something like:
>>>
>>> Variable: ts
>>> Type: float
>>> Total Size: 414056448 bytes
>>> 103514112 values
>>> Number of Dimensions: 3
>>> Dimensions and sizes: [time | 1872] x [lat | 192] x [lon | 288]
>>> Coordinates:
>>> time: [15.5..56924.5]
>>> lat: [ -90.. 90]
>>> lon: [ 0..358.75]
>>>
>>> Note that under the "Coordinates" section it actually gives you the list
>>> of coordinate arrays associated with your variable "ts", which tells you
>>> that you have a rectilinear grid.
>>>
>>> 2) curvilinear
>>>
>>> You have a 2D data array dimensioned nlat x nlon, and the latitudes AND
>>> longitudes are represented by 2D arrays of size nlat x nlon. The WRF data
>>> you read in is a curvilinear grid, because XLAT and XLONG are both 2D
>>> arrays of the same dimensionality.
>>>
>>> 3) unstructured
>>>
>>> Here you don't have a "gridded" data array, but rather a structure like
>>> a triangular mesh or a hexagonal grid. I'm not going to go into this one
>>> since this is not what you are dealing with here.
>>>
>>> In practice, your source and destination grids can be any of these
>>> types, and hence the dimensions do not have to match. The idea behind
>>> regridding is that you are trying to get your data that is on some
>>> particular grid ("source" grid), onto a *different* grid ("destination"
>>> grid), so that you can perhaps you can do array calculations on the
>>> regridded data with some other variable on the same destination grid.
>>>
>>> In your case, your source grid (the WRF grid) is a curvilinear grid, and
>>> the script you are using is regridding it to a rectilinear grid, so it's
>>> correct that you are getting this:
>>>
>>> (0) write_grid_description: source lat dims = (281,353)
>>> (0) write_grid_description: source lon dims = (281,353)
>>> (0) write_grid_description: source grid type is 'curvilinear'
>>> (...)
>>> (0) write_grid_description: destination lat dims = (281)
>>> (0) write_grid_description: destination lon dims = (353)
>>> (0) write_grid_description: destination grid type is 'rectilinear'
>>>
>>> I believe this script is based on the same one used by ESMF_regrid_5.ncl
>>> at:
>>>
>>> http://www.ncl.ucar.edu/Applications/ESMF.shtml#ex5
>>>
>>> As a side, I'm not sure why you are doing this:
>>>
>>> dst_lat = fspan(lat_south,lat_north,src_lat)
>>> dst_lon = fspan(lon_west,lon_east,src_lon)
>>>
>>> The "fspan" function is a very basic function where you give it a start
>>> value, an end value, and the number of equally-spaced values you want to
>>> span between those two values. For example:
>>>
>>> x = fspan(1,5,4) ; 1, 2.3333, 3.666667, 5
>>>
>>> You are trying to give "fspan" an array of latitudes and longitudes for
>>> the third argument which makes no sense and simply won't work.
>>>
>>> Backing up a bit here, why are you trying to regrid your WRF "tc"
>>> variable before you call wrf_user_intrp3d? Couldn't you simply subscript
>>> tc using the lat/lon indexes you calculated, and pass this to
>>> wrf_user_intrp3d?
>>>
>>>
>>> --Mary
>>>
>>>
>>>
>>> On Tue, Apr 26, 2016 at 3:10 PM, Ryan Connelly <rconne01 at gmail.com>
>>> wrote:
>>>
>>>> Follow-up: I had my lat and lon arrays switched. Fixed that. But the
>>>> error still persists.
>>>>
>>>> It seems to be a Catch 22. Right now, I have
>>>>
>>>> locSW = wrf_user_ij_to_ll(a,1.,1.,True) ; SW corner of domain
>>>> for lat and lon minima. Func is fortran-based so 1 not 0
>>>> lon_west = locSW(0)
>>>> lat_south = locSW(1)
>>>>
>>>> ; Use any variable that spans the entire grid to get maxima of i,j
>>>> ; which will then be used to get lat, lon of upper right (NE) corner
>>>>
>>>> grid_size = dimsizes(tc) ; z is 0th index, lat
>>>> 1st, lon 2nd
>>>> jMax = grid_size(1)
>>>> iMax = grid_size(2)
>>>>
>>>> locNE = wrf_user_ij_to_ll(a,iMax,jMax,True) ; NE corner of
>>>> domain for lat and lon maxima. Func is fortran-based so max not max-1
>>>> lon_east = locNE(0)
>>>> lat_north = locNE(1)
>>>>
>>>> n = dimsizes(lat)
>>>> m = dimsizes(lon)
>>>>
>>>> nlat = n(0)
>>>> mlon = m(1)
>>>>
>>>> dst_lat = fspan(lat_south,lat_north,nlat)
>>>> dst_lon = fspan(lon_west,lon_east,mlon)
>>>>
>>>> which means that element (2) of fspan has 1 dimension. Therefore, in
>>>> the output, I see:
>>>>
>>>> (0) write_grid_description: source lat dims = (281,353)
>>>> (0) write_grid_description: source lon dims = (281,353)
>>>> (0) write_grid_description: source grid type is 'curvilinear'
>>>> (...)
>>>> (0) write_grid_description: destination lat dims = (281)
>>>> (0) write_grid_description: destination lon dims = (353)
>>>> (0) write_grid_description: destination grid type is 'rectilinear'
>>>>
>>>> which seems like it should not be. Shouldn't I want(need) the
>>>> dimensions of the source and destination grid to match?
>>>>
>>>> So then, in fspan, I switch nlat to src_lat and mlon to src_lon, making
>>>> that element two-dimensional instead of one-dimensional:
>>>>
>>>> dst_lat = fspan(lat_south,lat_north,src_lat)
>>>> dst_lon = fspan(lon_west,lon_east,src_lon)
>>>>
>>>> Yet when I run with that change, I get: fatal:Number of dimensions in
>>>> parameter (2) of (fspan) is (2), (1) dimensions were expected
>>>>
>>>> How can NCL simultaneously be expecting a one- and two-dimension
>>>> array? I'm very confused here.
>>>>
>>>> Ryan
>>>>
>>>> On Tue, Apr 26, 2016 at 2:16 PM, Ryan Connelly <rconne01 at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I'm using ESMF_WRF_to_rect.ncl to regrid (
>>>>> https://www.ncl.ucar.edu/Applications/Templates/ESMF_WRF_to_rect.ncl).
>>>>> Regridding completes fine, but then when i try to interpolate the regridded
>>>>> variable to an isobaric plane using wrf_user_intrp3d I get:
>>>>>
>>>>> fatal:Dimension size mismatch, dimension (1) of left hand side
>>>>> reference does not have the same size as the right hand side reference
>>>>> after subscripting.
>>>>>
>>>>> This is a pretty literal error message and one that I've fixed before,
>>>>> but this time it has me stumped. I haven't even declared the variable on
>>>>> the left hand side until this particular line (and I've double checked that
>>>>> by issuing a printVarSummary and having it throw a variable undefined
>>>>> error) so how can the dimension sizes not match if this is a blank new
>>>>> variable?
>>>>>
>>>>> I then decided to be extra super literal and declare a new array with
>>>>> the right dimensions before calling wrf_user_intrp3d, but the error
>>>>> persists:
>>>>>
>>>>> (...)
>>>>> tc_rect = ESMF_regrid(tc,Opt) ; Do the regridding
>>>>>
>>>>>
>>>>> ; Interpolate to isobaric planes
>>>>>
>>>>> pressure = 850.
>>>>>
>>>>> newdim = (dimsizes(tc_rect))
>>>>> print(newdim)
>>>>>
>>>>> tc_rect_plane =
>>>>> new((/newdim(0),newdim(1),newdim(2)/),typeof(tc_rect))
>>>>>
>>>>> tc_rect_plane = wrf_user_intrp3d(tc_rect,p,"h",pressure,0.,False)
>>>>> (...)
>>>>>
>>>>> I'm out of ideas here.
>>>>>
>>>>> Ryan
>>>>>
>>>>> --
>>>>> Ryan Connelly
>>>>> M.S. Student in Atmospheric Sciences, Stony Brook University
>>>>> B.S. in Meteorology with Minors in Mathematics and GIS, Valparaiso
>>>>> University
>>>>> rconne01 at gmail.com
>>>>> ryan.connelly at stonybrook.edu
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Ryan Connelly
>>>> M.S. Student in Atmospheric Sciences, Stony Brook University
>>>> B.S. in Meteorology with Minors in Mathematics and GIS, Valparaiso
>>>> University
>>>> rconne01 at gmail.com
>>>> ryan.connelly at stonybrook.edu
>>>>
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>>>>
>>>
>>
>>
>> --
>> Ryan Connelly
>> M.S. Student in Atmospheric Sciences, Stony Brook University
>> B.S. in Meteorology with Minors in Mathematics and GIS, Valparaiso
>> University
>> rconne01 at gmail.com
>> ryan.connelly at stonybrook.edu
>>
>
>
--
Ryan Connelly
M.S. Student in Atmospheric Sciences, Stony Brook University
B.S. in Meteorology with Minors in Mathematics and GIS, Valparaiso
University
rconne01 at gmail.com
ryan.connelly at stonybrook.edu
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