[ncl-talk] Fwd: Adding two arrays - with missing values in different rows and columns

[Rashed Mahmood]

Sorry, forgot to add ncl-talk, see below.

---------- Forwarded message ---------
From: Rashed Mahmood <rashidcomsis at gmail.com>
Date: Sat, Apr 2, 2022 at 8:38 PM
Subject: Re: [ncl-talk] Adding two arrays - with missing values in
different rows and columns
To: JETAL SUTARIYA <jetal164 at email.arizona.edu>


Hi Jetal,
I do not think that the way you are trying to get the sum is the correct
way to get your desired results.

I think you need to use dimension sum function, e.g. something as:

Assuming that you are using a loop/or some select time steps, as x=1,2,3,...

combVar=var3(0:1,:,:)  ; tric to define a variable with metadata
combVar=var3 at _FillValue ;
combVar(0,:,:)=var3(x,:,:)
combVar(1,:,:)=var4(x,:,:)

var5 = dim_sum_n_Wrap(combVar,0)  ; This will sum if both var3 and var4 are
not missing, otherwise will use values from either var3 or var4 (whichever
is not missing). It will result in missing if both values are missing.

delete(combVar)   ; delete before next iteration.

HTH
Rashed




On Sat, Apr 2, 2022 at 3:07 PM JETAL SUTARIYA via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Hi NCL user community,
>
> I am trying to add two arrays: SMAP soil moisture L3 am and pm arrays, to
> obtain total soil moisture.
> Soil moisture total(var5) is var3+var4 but when there are missing values
> in either of those arrays, then var5 is also having missing values.
> Instead, I want to use sm_pm(var4) when sm_am(var3) is having missing values
> and if sm_pm(var4) is having missing values then use sm_am(var3), and when
> both are having nonmissing values then sum them. I guess NCL does not
>
> I use below code but var5 is solved for line 3 of the code rather than
> both the line 3 and line 4, so where var4 is missing it does not use var3
> value:
>  var3 = sm_am(x,:,:) ;sm_am = soil moisture am data x = time dimension
>  var4 = sm_pm(x,:,:) ;sm_pm = soil moisture pm data x = time dimension
>  var5 = where(ismissing(var3), var4, var3+var4)
>  var5 = where(ismissing(var4), var3, var3+var4)
>
> Please suggest a way to get the correct total soil moisture array such
> that these conditions are satisfied.
>
> I appreciate your help in finding a solution.
>
> Thank you,
> Jetal
>
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