# [ncl-talk] Calculating Barotropic streamfunction and AMOC using data with missing values?

Michael Hemming michael.hemming at mpimet.mpg.de
Tue Sep 2 05:16:05 MDT 2014

```Hello,

I have been struggling to calculate Barotropic streamfunction and AMOC
using online examples and function but I have recently been told it is
due to the fact that the data I use contains missing values, therefore
all values are set to the missing value.

How can I somehow ignore the missing values during calculation?

Here is my code for the bartropic streamfunction:

----------------------------------------------------------------------------------------------------------------------------------------------------

begin

;##########################################################################
;##########################################################################
;-------------------------Barotropic Plots---------------------------------
;--------------------------------------------------------------------------
;##########################################################################
;##########################################################################

;ICON

u             = noshupw->u_vint_acc
u&lon            = u&lon-360     ; Fix the longitudes to be < 360
lat             = noshupw->lat

v             = noshupw->v_acc

printVarSummary(u)
printVarSummary(v)

dimUV= dimsizes(barai)

klev = 20 ; number of levels in total

sf = v(:,{klev},:,:)
vp = v(:,{klev},:,:)
sf at long_name = "stream function"
vp at long_name = "velocity potential"
sf at units = "m^2/s"
vp at units = "m^2/s"

printVarSummary(sf)
printVarSummary(vp)

uv2sfvpg(u,v,sf,vp)

----------------------------------------------------------------------------------------------------------------------------------------------------

and my AMOC code is largely based on the online example moc_1.ncl

thanks,
Michael

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