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I want to calculate vertically integrated moisture flux convergence (VIMFC) in GrADS.

But when I give the following instruction it marks me errors:

sdfopen shum.mon.mean.nc
sdfopen uwind.mon.mean.nc
sdfopen vwind.mon.mean.nc

set lon 180 320
set lat 0 60
set t 763 766
set lev 1000 300

qu=vint(1000,shu,.1*uwnd.2,300)
qv=vint(1000,shu,.1*vwnd.3,300)

vimf=-hdivg(qu,qv)
d vimf

ga-> qu=vint(1000, shum.1*uwnd.2,600)

Error from VINT: 

Incompatible grids.
*** glibc detected *** grads: double free or corruption (!prev): 0x0000000003707c40 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.

6(+0x7e846)[0x7f898ac4c846]
grads(gree+0x2bb)[0x4fab92]
grads(gadef+0x126b)[0x518144]
grads(gacmd+0x16c)[0x52af24]
grads(main+0xa7a)[0x4975ab]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f898abef76d]
grads[0x4960a9]
======= Memory map: ========
00400000-00bcb000 r-xp 00000000 08:05 1573111
7f898bdc2000-7f898bdc3000 r--p 00017000 08:05 1572886                    /lib/x86_64-linux-gnu/libpthread-2.15.soAborted (core dumped)

Does anyone know how to fix it?

Best, Pablo Camarena

f.thorpe
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Pablo Camarena
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    have you checked the grids of your input files to see if they match? It does say "Incompatible grids." – f.thorpe May 31 '17 at 03:01
  • That'd be my first guess too. I remember GrADS being annoyingly uninformative during errors like yours – JeopardyTempest May 31 '17 at 06:02
  • I have come across the same problem. Some time ago, I have started using Matlab and R. Things have become more transparent. For some starting reference, I suggest taking a look at this topic: https://earthscience.stackexchange.com/a/10667/8396 – ouranos Jun 28 '17 at 13:53

1 Answers1

1

you can use this: this define integrated vapor transport(IVT) or Moisture Flux:

 'define qu=vint(const(lon,1000,-a),shum.1*uwind.2,300)'  
 'define qv=vint(const(lon,1000,-a),shum.1*vwind.3,300)'  
 'define VIMFC=mag(qu,qv)'
 'd VIMFC'

best regards

JeopardyTempest
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Aminollah Ghahramani
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