[ncl-talk] Question on interpolation

[Dennis Shea]

I assume you are processing multiple GRIB2 files using *addfiles.*
This is appropriate if the same grid is applicable to all files.
*addfiles *will concatenate all the file times. You only need to use one
grid.
---
In the case of the HWRF grids (possibly) changing at each time step, you
will have to step through the files manually. This means you will have to
do some book-keeping.

  dirHWRF = "..."
  filHWRF  = "..."
  pthHWRF = dirHWRF + filHWRF
  nfil = dimsizes(filHWRF)

  SLAT =    ; one or more Sonde lat
  SLON =

  do nf=0,nfil-1
       f = addfile(pthHWRF(nf),"r")
       x = f->X
       xsonde(nf.....) =  *linint2_points*(x&lon_0, x&lat_0,
False,SLAT,SLON 0)

     end do

Good Luck

On Tue, Sep 3, 2019 at 1:19 PM Andrew Kren - NOAA Affiliate via ncl-talk <
ncl-talk at ucar.edu> wrote:

> Dear ncl-talk,
>
> I am working to interpolate a high-resolution model dataset (HWRF) to the
> time and location of a dropsonde location. In the past for other datasets,
> I have used linint1_n and linint2_points to interpolate in time and space
> to the dropsonde position.
>
> However, HWRF, which is 6-hour analysis output, has a varying grid every 6
> hours as the domain "moves" with the tropical cyclone. Hence, the lat/lon
> locations are not fixed in time. They have the same dimension sizes but the
> points vary depending on the cyclone center. This led to an error in my
> linint2_points function:
>
> fatal:linint2_points: If xi is not one-dimensional, then it must have one
> less dimension than fi
>
>
>
> I know why this is happening. I read in two HWRF files around the
> dropsonde time to do the interpolation. I used "join" to join the files and
> my lat/lon arrays are (time, lat) and (time, lon). So I get the error.
>
>
> But my question is how best to proceed? This is technically not an
> unstructured grid, but could be considered one. Should I use ESMF?
>
>
> Thanks,
>
> --
> Andrew Kren
> Assistant Scientist
> University of Miami CIMAS - NOAA/AOML
> Global Observing Systems Analysis (GOSA) Group
> NOAA/AOML Quantitative Observing System Assessment Program (QOSAP)
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