[gradsusr] prolems with nested global area using const and atot

[Andrew Friedman]

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On Oct 11, 2013, at 9:02 PM, Andrew Friedman <andfried at berkeley.edu> wrote:

> Hi GrADS users,
> 
> I'm getting different answers in a global area calculation combining const with atot after setting x-values. This difference seems to depend on whether I do the calculation in 1 or 2 steps.
> 
> Following example 1 from atot (http://www.iges.org/grads/gadoc/gradfuncatot.html),
> I have a SST dataset (attached) with longitude dimensions of -180 to 180.
> 
> METHOD 1: one-step calculation
> ga-> sdfopen sst_timeslice.nc
> ga-> set lon -180 180
> ga-> d atot(const(sst,1,-a),g)
> Result value = 12.5664
> 
> METHOD 2: 2-step caclulation
> ga-> sdfopen sst_timeslice.nc
> ga-> set lon -180 180
> ga-> sst1=const(sst,1,-a)
> ga-> d atot(sst1,g)
> Result value = 6.45772
> 
> Can anyone explain what is going on? Is this the intended behavior?
> 
> Thanks,
> Andrew
> 
> ---------------------------------------------------------------------
> Andrew Friedman
> Graduate student, UC Berkeley Geography
> andfried at berkeley.edu