Geeta,<br>The documentation on the tvrh2q function says that it will assume it is at the pressure level of the current dimension environment.� I don't see any "set lev" commands that are uncommented, so one of the reasons you are not getting the data is probably because your pressure level is not set correctly.� Nonetheless, I should think the while loop should work just fine, but you need to be careful how you set your limits.� If you want to go from low levels to upper levels, your while statement should look something like<br>
<br>i = 1 ; zlev = 1000<br>while (zlev > 100)<br>...<br>...<br>...<br>zlev = zlev - dp*i��� (where dp is your pressure change between levels...hopefully it is constant.� If it isn't there's another way to do this)<br>
i = i + 1<br>endwhile<br><br>Try that and see if it works.<br><br>Jeff Duda<br><br><div class="gmail_quote">On Mon, Oct 25, 2010 at 3:53 AM, Geeta Geeta <span dir="ltr"><<a href="mailto:geeta124@hotmail.com">geeta124@hotmail.com</a>></span> wrote:<br>
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Dear All, <br>I am trying to extract the SPECIFIC HUMIDITY for all the levels in vertical (19 Levels from 1000 to 100hPa) from the Model. <br>So I am Using tvrh2q function of Grads. Following is the ctl file. <br><br>'open test.ctl'<br>
*'set lev 1000 100'<br>'set t 1'<br>�* while (lev< 100)<br>*zlev=1000<br>'set gxout fwrite'<br>'set fwrite test.dat'<br>�zlev =1000<br>'define tvk=tk(lev='zlev')+0.61*QVAPOR(lev='zlev')*tk(lev='zlev')'<br>
'd tvrh2q(tvk(lev='zlev'),rh(lev='zlev'))'<br>************<br>�zlev =950<br>'define tvk=tk(lev='zlev')+0.61*QVAPOR(lev='zlev')*tk(lev='zlev')'<br>'d tvrh2q(tvk(lev='zlev'),rh(lev='zlev'))' <br>
*'disable fwrite'<br>*****************<br>�zlev =900<br>'define tvk=tk(lev='zlev')+0.61*QVAPOR(lev='zlev')*tk(lev='zlev')'<br>'d tvrh2q(tvk(lev='zlev'),rh(lev='zlev'))' <br>
'disable fwrite'<br>***********************<br><br>* endwhile<br><br>I am Unable to Extract the data Using the While Statement in Grads, so I am defining the Zlev separately . <br><br>Kindly Suggest. <br>geeta<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Jeff Duda<br>Iowa State University<br>Meteorology Graduate Student<br>3134 Agronomy Hall<br><a href="http://www.meteor.iastate.edu/~jdduda">www.meteor.iastate.edu/~jdduda</a><br>