[ncl-talk] How to interpolate precipitation without losing much confidence?

[Dennis Shea]

 There is no builtin function, As suggested by Dave:

  **UNTESTED**  you nay have to make sure this is correct.

  nm     =  3
  nlat24  =
  mlon24 =
  prc8   = prc24(1:nlat24-2:mn,1:mlon24-2:mn)
  prc8   = prc24 at _FillValue
  printVarSummary(prc8)

  dims_prc8 = dimsizes(prc8)
  nlat8 = dims_prc8(0)
  mlon8 = dims_prc8(1)
  print(dims8_prc8)

; This does a straight arithmetic average.

  do nl=1,nlat24-2,mm
    do ml=1,mlon24-2,mn
         prc8(nl/mn,ml/mn) = (prc24(nl+1,ml-1)+prc24(nl+1, ml
)+prc24(nl+1,ml+1) \
                                          +prc24(nl   ,ml-1)+prc24(nl   ,
ml )+prc24(nl     ,ml+1)\
                                          +prc24(nl-1,ml-1)+prc24(nl-1, ml
)+prc24(nl-1,ml+1))/9.0
    end do
   end do

On Thu, Oct 1, 2020 at 9:59 AM Dave Allured - NOAA Affiliate via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> In NCL, this kind of operation falls under regridding, not interpolation.
> I recommend one of the area averaging functions, such
> as area_conserve_remap, area_hi2lores, or ESMF_regrid.
>
> None of those functions use the grid box calculation that you specified.
> If you want to perform that exact calculation over all grid boxes falling
> in a 1/8 degree box, you will need to write your own NCL code.  I suggest
> that you use the dim_avg_n function inside a double loop over all output
> points on the 1/8 degree grid.  "There is more than one way to do this."
>
>
> On Thu, Oct 1, 2020 at 8:58 AM Xueyan Zhang via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
>> Hello NCL,
>>
>> I want to interpolate precipitation data from 1/24 degree to 1/8 degree.
>> The way I wanna do it is to: calculate the average of all grid boxes
>> falling in a 1/8 degree box? Is there any function in NCL?
>>
>> Thanks!
>>
>> Xueyan
>>
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