Jose,<br>I do not have a script that will use the omega equation, but the kinematic method uses vertically integrated divergence, which is very simple to implement:<br><br>'define omega = vint(psfc,hdivg(u,v),500)'<br>
<br>The above example assumes <br>1) you have data on pressure surfaces<br>2) the variable representing surface pressure is psfc<br>3) the variables representing the horizontal wind components are u and v<br>4) you want to find omega at 500 mb<br>
5) you have no vertical velocity at the surface<br><br>Given the simplicity of this method, it can give errant results, but the general pattern should be represented. To make the kinematic method a better approximation, you can use the methods in <a href="http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2008/pdfNwIUpObZBI.pdf">O'Brien (1970).</a><br>
<br>Hope this helps.<br><br>Jeff Duda<br><br><div class="gmail_quote">On Wed, Aug 31, 2011 at 4:08 PM, veiga <span dir="ltr"><<a href="mailto:veiga.uea@gmail.com">veiga.uea@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div style="word-wrap:break-word"><div>Dear GrAds users,</div><div><br></div><div>Is there someone who knows where I can find a GrAds script which computes the vertical velocity through the omega equation? </div><div>Other methods like kinematic, adiabatic and quase-geostrophic relative vorticity, are welcome as well. </div>
<div><br></div><div>Any hint will be very appreciated.</div><div><br></div><div>Cheers,</div><br><div>
<div style="word-wrap:break-word"><div><span style="font-family:arial;font-size:small"><div><span style="font-family:arial, sans-serif;font-size:13px;border-collapse:collapse"><font color="#333333"><span style="background-color:rgb(255, 255, 255)">José Augusto P. Veiga, </span><br>
<br>======================================<br>Universidade do Estado do Amazonas <br>Departamento de Meteorologia<br><span style="border-collapse:separate;font-family:arial;font-size:small">Escola Superior de Tecnologia (EST)</span><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><a href="http://www.meteor.iastate.edu/%7Ejdduda" target="_blank">www.meteor.iastate.edu/~jdduda</a><br>