[ncl-talk] Querry regarding wind shear area average plot

[Dennis Shea]

I hesitate to answer this because I do not want to end up doing the
programming.
*You must do the work.*

To get you started:

  u(nens,time,lev,lat,lon), v(nens,time,lev,lat,lon)

  pHigh   = 250
  pLow    = 850
  ushear = u(:,:,{pHigh,:,:)-u(:,:,{pLow},:,:)
  vshear = v(:,:,{pHigh},:,:)-v(:,:,{pLow},:,:)
  ushear at long_name = "USHEAR: ("+pHigh+"-"+pLow+")"
  vshear at long_name = "VSHEAR: ("+pHigh+"-"+pLow+")"
  ushear at units           = u at units
  vshear at units           = v at units
  copy_VarCoords(u(:,:,0,:,:), ushear)
  copy_VarCoords(v(:,:,0,:,:), vshear)

  printVarSummary(ushear)                          ; (nens,time,lat,lon)
  printVarSummary(vshear)

  shear = sqrt(ushear^2 + vshear^2)
  shear at long_name = "SHEAR"
  shear at units     = ushear at units
  copy_varCoords(ushear, shear)
  printVarSummary(shear)

----
Perhaps:

[1] clat(nens,ntim) and clon(nens,ntim)  ; storm center for each ensemble
member at each time.
[2] Use *gc_latlon*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/gc_latlon.shtml> to
calculate the distance from the storm center(s)
[3] Calculate areal means according to distance.

----
Another example that might be useful:
*http://www.ncl.ucar.edu/Applications/regrid.shtml*
<http://www.ncl.ucar.edu/Applications/regrid.shtml>
See Example: regrid_15.ncl

Download: *http://www.ncl.ucar.edu/Applications/Scripts/grid2geocircle.ncl*
<http://www.ncl.ucar.edu/Applications/Scripts/grid2geocircle.ncl>
**Carefully* *read the documentation



On Fri, Nov 29, 2019 at 9:44 AM Goriparthi Pavani via ncl-talk <
ncl-talk at ucar.edu> wrote:

> Hi,
> I want to plot magnitude of shear for each ensemble member by taking
> average of the difference in wind velocities between the 850 hPa and 250hPa
> levels at every grid point that is between 200 and 500km from the surface
> center for a tropical cyclone.
> Domain used is moving nest with 3km resolution.
>
> Could you please help me with the ncl script to do the area average of
> wind shear magnitude between 200 and 500km from surface center.
>
> Regards
> Pavani
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20191205/e73cd1a7/attachment.html>