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

[Xueyan Zhang]

Thanks! I'll check it out! It's just time consuming if I use loops...

Xueyan

On Thu, Oct 1, 2020 at 9:23 AM Dennis Shea <shea at ucar.edu> wrote:

> 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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