[gradsusr] Help in showing the example of using fndlvl(), max() and maxloc()

[See Hai Ooi]

--- On Sun, 28/3/10, See Hai Ooi <axl419 at yahoo.com> wrote:


From: See Hai Ooi <axl419 at yahoo.com>
Subject: Re: [gradsusr] Help in showing the example of using fndlvl(), max() and maxloc()
To: gradsusr at gradsurs.org
Cc: sushantpuranik at gmail.com, Charles.Seman at noaa.gov, subra.kumar at gmail.com
Date: Sunday, 28 March, 2010, 11:18 PM







Hi Sushant,
 
       Sorry to inform you that the previous script happened to work (?) for 4 vertical pressure levels but it failed when the levels were reduced to three.  I just emailed you a corrected version of the script under different subject heading and it works for any number of vertical pressure levels you need.  
 
       It appears to me that you are interested to identify the low level jets over the Indian Ocean.  What is your definition of llj ?   Below is what I know about llj:-
 
· Fast moving current of air near the surface. 
· Large wind shear above and below the jet level. 
· Maximum wind speed at least 12-16 m/s (peak speeds up to 30 m/s observed) 
· Wind speed above jet 50-75% or less of the maximum. 
· Strong lateral shear on both sides. Width typically about 200-300 km.
 
     Using our corrected script for the lowest three levels (1000, 925 and 850 hPa), I obtained the following results over your defined area in January 2008 :-
 
    time index     maximum wind (m/s)     level (hPa)           location
   --------------     --------------------------     --------------           ------------
      120                20.512                             925                      30N     37.5E
      124                21.0772                           925                      17.5S   57.5E
      128                18.4618                           925                      22.5N   52.5E
      132                18.111                             850                      5N        50E
      136                19.47                               850                      7.5S      77.5E
 
       My above elaboration is meant merely to alert you to use the right script (might have been written by some other GrADS users) to attain your intended objective.  
 
       To plot the path of your llj, you can write your  results in a text file with the following format:-
 
       date    time     xgrd     ygrd     max
       ...         ....        ....         ....         .....
 
       Then write a script to read the text file with the following lines :-
      .............
       xpos = xgrd
       ypos = ygrd
       'draw mark 1 'xpos' 'ypos' .2'
      ............
      
      Hope this helps.
 
Ooi
 
 
- On Sun, 28/3/10, sushant puranik <sushantpuranik at gmail.com> wrote:

From: sushant puranik <sushantpuranik at gmail.com>
Subject: Re: [gradsusr] Help in showing the example of using fndlvl(), max() and maxloc()
To: "See Hai Ooi" <axl419 at yahoo.com>
Date: Sunday, 28 March, 2010, 7:43 PM

Hi Ooi
Thank you for the script. It works .
It gives me the maximum value of wind at particular level and also the point at which it is maximum.

Thank you for the script and also for the suggestions.

If you dont mind i would like to ask you one more question .
 How can i make a plot to see the path of a jet stream.

Any suggestions.

Thank you again 

Sushant


Get your preferred Email name! 
Now you can @ymail.com and @rocketmail.com.


      Get your preferred Email name!
Now you can @ymail.com and @rocketmail.com. 
http://mail.promotions.yahoo.com/newdomains/aa/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20100328/8d8de7e8/attachment-0003.html