[gradsusr] use of vint for an area

See Hai Ooi axl419 at yahoo.com
Fri Aug 27 00:05:20 EDT 2010


Dear Rashed Mahmood,
 
         Thank you.
 
         I have no problem in deriving the correct unit.  But, as I told Sushant Puranik, I am not comfortable with the vint() function.  I downloaded the NCEP/NCAR Reanalysis data and used my modified script to generate similar analysis as that in the paper by Professor Krishnamurti (please see the attachment).  You can see that the two outputs are vastly different.  I believe Prof Krish's analysis should be correct (I would be very pleased to know if someone can tell me how he did it.).  This implies that the algorithm of vint() of GrADS could be defective.  Can anyone enlighten me ?
 
       Best regards.
 
Ooi
 
 


--- On Thu, 26/8/10, Rashed Mahmood <rashidcomsis at gmail.com> wrote:


From: Rashed Mahmood <rashidcomsis at gmail.com>
Subject: Re: [gradsusr] use of vint for an area
To: "GrADS Users Forum" <gradsusr at gradsusr.org>
Date: Thursday, 26 August, 2010, 10:09 PM



Hi  OOI 
 
 
I don't know exactly but your question about the units can be solved if you divide the variable 'shum' by 1000 to make it kg/kg as in NCEP data it given as grams/kg.
 
 
hope it works
 
Cheers
Rashed


 
On Wed, Aug 25, 2010 at 3:19 PM, See Hai Ooi <axl419 at yahoo.com> wrote:






Dear Sushant Puranik,
 
          Thank you !
 
          My purpose of writing a GrADS script using vint() is to obtain the vertically integrated moisture transport vector fields as shown in the paper by Professor Krishnamurti (attached).  However, by adapting your method, I notice that the magnitude of vector scale is 1000 instead of 0.2 etc (see spmtest.doc).  What is the unit of the output ? Something is missing and hope you can enlighten me.  Should I use the rotational motion fields from the streamfunctions instead of the pure wind vectors to obtain the mositure transport ?  I am also interested to have script to compute the dry and moist static energies, if available.
 
         Best regards.
 
(Mr) OOI See-hai
 


--- On Wed, 25/8/10, sushant puranik <sushantpuranik at gmail.com> wrote:


From: sushant puranik <sushantpuranik at gmail.com>
Subject: Re: [gradsusr] use of vint for an area
To: "GrADS Users Forum" <gradsusr at gradsusr.org>
Date: Wednesday, 25 August, 2010, 1:59 PM 





Hello Ooi See Hai
I am using grads on Linux (FC 8) OS. Earlier while trying VINT() i also came across the same problem.
After that i adopted following procedure

[Sushant at atmmtech1 ~]$ gradsnc

Grid Analysis and Display System (GrADS) Version 1.8SL11
Copyright (c) 1988-2001 by Brian Doty 
Center for Ocean-Land-Atmosphere Studies
Institute for Global Environment and Society 
All Rights Reserved

Config: v1.8SL11 32-bit little-endian readline sdf/xdf netcdf lats printim

Issue 'q config' command for more information.

Landscape mode? (no for portrait):  
GX Package Initialization: Size = 11 8.5 
ga-> c
ga-> sdfopen /home/Sushant/Desktop/NcepSpecifichumidity/shum.1989.nc 
Scanning self-describing file:  /home/Sushant/Desktop/NcepSpecifichumidity/shum.1989.nc
Found 1 data variables in SDF file.
Found displayable variable shum with 8 levels in SDF file.
SDF file /home/Sushant/Desktop/NcepSpecifichumidity/shum.1989.nc is open as file 1
LON set to 0 360 
LAT set to -90 90 
LEV set to 1000 1000 
Time values set: 1989:1:1:0 1989:1:1:0 
ga-> sdfopen /home/Sushant/Desktop/Ncepmeriwind/data/vwnd.1989.nc    
Scanning self-describing file:  /home/Sushant/Desktop/Ncepmeriwind/data/vwnd.1989.nc
Found 1 data variables in SDF file.
Found displayable variable vwnd with 17 levels in SDF file.
SDF file /home/Sushant/Desktop/Ncepmeriwind/data/vwnd.1989.nc is open as file 2
ga-> set gxout shaded
ga-> set lev 1000
LEV set to 1000 1000 
ga-> define a=(shum*vwnd.2)
Define memory allocation size = 42340 bytes
ga-> define b=vint(lev,a,300)
Define memory allocation size = 42340 bytes
ga-> d b
Contouring: -1500 to 1200 interval 300 

and the output of it i have attached here with this mail.

regards 

Sushant Puranik
Dept. of Atmospheric & Space Sciences,
University of Pune,
Pune-07,
India.




On Tue, Aug 24, 2010 at 11:14 AM, See Hai Ooi <axl419 at yahoo.com> wrote:






Dear Mr Arlindo,
 
            It appears to me that the vint function is only valid for a point.  When I employed it for an area, I encountered the following problem (I use window version of GrADS under VISTA OS) :-
 
C:\>grads 
Starting X server under \Resources\Xming 
Starting grads under c:\OPENGR~1\Contents\Cygwin\Versions\20A7OG~1.3\i686 ... 
  
Grid Analysis and Display System (GrADS) Version 2.0.a7.oga.3 
Copyright (c) 1988-2008 by Brian Doty and the 
Institute for Global Environment and Society (IGES) 
GrADS comes with ABSOLUTELY NO WARRANTY 
See file COPYRIGHT for more information 
  
Config: v2.0.a7.oga.3 little-endian readline printim grib2 netcdf hdf4-sds hdf5 
opendap-grids,stn athena geotiff 
Issue 'q config' command for more information. 
Loading User Defined Extensions table </bin/gex/udxt> ... ok. 
Landscape mode? ('n' for portrait): 
GX Package Initialization: Size = 11 8.5 
ga-> sdfopen i:\laptop\cdc\shum\shum.2010.nc 
Scanning self-describing file:  i:\laptop\cdc\shum\shum.2010.nc 
SDF file i:\laptop\cdc\shum\shum.2010.nc is open as file 1 
LON set to 0 360 
LAT set to -90 90 
LEV set to 1000 1000 
Time values set: 2010:1:1:0 2010:1:1:0 
E set to 1 1 
ga-> a=vint(1000,shum,500) 
Error from VINT:  Incompatible grids. 
Define memory allocation size = 84680 bytes 
      6 [main] grads 3100 _cygtls::handle_exceptions: Exception: STATUS_ACCESS_V 
IOLATION 
Exception: STATUS_ACCESS_VIOLATION at eip=610C3938 
eax=5F676E69 ebx=11A74040 ecx=00000026 edx=7373696D esi=00000069 edi=11A73E48 
ebp=00000328 esp=0022A9D0 program=C:\OpenGrADS\Contents\Cygwin\Versions\2.0.a7.o 
ga.3\i686\grads.exe, pid 3100, thread main 
cs=001B ds=0023 es=0023 fs=003B gs=0000 ss=0023 
Stack trace: 
Frame     Function  Args 
   6910 [main] grads 3100 _cygtls::handle_exceptions: Exception: STATUS_ACCESS_V 
IOLATION 
   8471 [main] grads 3100 _cygtls::handle_exceptions: Error while dumping state 
(probably corrupted stack) 

        Can you help to resolve my problem ?
 
        Thank you and best regards.
 
Sincerely,
 
Ooi See Hai


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20100826/e8a43472/attachment-0003.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: spmtest2.doc
Type: application/msword
Size: 84480 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20100826/e8a43472/attachment-0003.doc 


More information about the gradsusr mailing list