[gradsusr] Vertical Integrated Moisture Transport (VIMT)

[Andrew Friedman]

HI Muhammad,

Can you calculate what the intermediate values are? That can help identify where the issue is.

Andrew

On May 9, 2014, at 1:06 PM, Muhammad Latif <latif_space at yahoo.com> wrote:

> Hi all,
> 
> I am trying to calculate Vertical Integrated Moisture Transport (VIMT) from surface to 500 hPa in units of kg/m/sec using grads function "vint(psexpr,expr,top)" only on the one time step.
> I used the following script to get VIMT:
> 
> 'sdfopen spr-daily.nc'         ;* spr is the surface pressure in Pa.
> 'set time 20jun1970'
> 'define surfpres=pres/100'     ;* /100 to convert in hPa
> 'close 1'
> 
> 'sdfopen shum-daily.nc'
> 'sdfopen uwnd-daily.nc'
> 'sdfopen vwnd-daily.nc'
> 
> 'set lat 0 45'
> 'set lon 50 100'
> 
> 'set time 20jun1970'
> 'define vintq=vint(surfpres,shum.1,500)'     ;*shum is the specific humidity in kg/kg
> 'define vintu=vint(surfpres,uwnd.2,500)'     ;*uwnd is the u component of wind in m/sec
> 'define vintv=vint(surfpres,vwnd.3,500)'     ;*vwnd is the v component of wind in m/sec
> 'define zon=(vintq*vintu)'
> 'define mer=(vintq*vintv)'
> 
> 'set gxout vector'
> 'd zon;mer'
> 
> Script runs successfully showing VIMT, but the magnitude of vector appears (4e+06) in the vector scale bar.
> I guess, this magnitude is not right. The value should lie around 20 or 40 (kg/m/sec). 
> 
> I'll be very thankful if anyone could help me to sort out the issue mentioned above.
> 
> Regards
> 
> Muhammad Latif
> PhD Scholar
> Department of Meteorology
> CIIT, Islamabad 
> 
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