[gradsusr] vertically integrated moisture flux

[Jennifer M Adams]

Hi, Pablo — 
Grads shouldn’t be dumping core on you, but at least you got a clue before it crashed. The grids of your shum.1 and uwnd.2 files apparently don’t match. Try using the lterp() function to interpolate in the lat/lon dimenions, something like this:

ga-> d vint(1000,shum.1*lterp(uwnd.2,shum.1),600)

In the script lines you posted, I noticed that the syntax here is incorrect:
> qu=vint(1000,shu,.1*uwnd.2,300)
> qv=vint(1000,shu,.1*vwnd.3,300)

change "shu,.1" to "shum.1"

If the problem is that the vertical levels are different in your data files, then you need to fix that. There’s a script in the library that may be helpful —ftp://cola.gmu.edu/grads/scripts/zinterp.gs.  I believe the vint() function is a bit fussy about the Z axis. The lterp() function does not do vertical interpolation. Please read the vint() function Usage Notes carefully (http://cola.gmu.edu/grads/gadoc/gradfuncvint.html) to make sure you’ve got everything right. If you’re still having trouble, please also include the output from "ncdump -c” on your data files, the version of GrADS you are using, and the shortest possible script that illustrates the error. 
—Jennifer


On May 30, 2017, at 2:18 PM, Pablo Camarena <jcamarena006 at gmail.com> wrote:

> Hi,
> 
> I want to calculate Vertically integarted moisture flux convergence (VIMFC)
> 
> 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
> 
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--
Jennifer Miletta Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
George Mason University