[ncl-talk] How to get second partial derivative of a variable

[Lyndz]

Dear NCL-experts,

*Details:*
I have mean sea level pressure data from NCEP-DOE reanalysis with the
following dimensions and sizes.

Dimensions and sizes: [time | 124] x [lat | 73] x [lon | 144]


*Problems*:
(a) I would like to get the second partial derivative of the mslp
separately for the lon and lat.
I would like to get their products later and save as a variable such as the
below image:
[image: image.png]

a gradient of a gradient or components of a laplacian?

*What I have so far:*

I have the following initial script but only for getting the first partial
derivative using CFD.

   diri = "."

   fp   = addfile ("mslp_jan_2017.nc", "r")

   p = fp->mslp(:,:,:)

;****************************************

; calculate pressure gradients via CFD

;****************************************


  p_gradLatLon  = grad_latlon_cfd (p, p&lat, p&lon, True, False)

  dpdY  = u_gradLatLon[0]

  dpdX  = u_gradLatLon[1]

  delete(p_gradLatLon)


  dpdX at long_name = "longitudinal gradient of MSLP"

  dpdX at units     = "P/m"                                         ;(Pa)*(1/m)
= Pa/m

  dpdY at long_name = "latitudinal gradient of MSLP"

  dpdY at units     = "Pa/m"

  printVarSummary(dpdX)

  printMinMax(dpdX,0)

  print("-------------")

  printVarSummary(dpdY)

  printMinMax(dpdY,0)

  print("-------------")



I'll appreciate any help on this.

Sincerely,

Lyndz
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