<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Hi Jeff, </div><div><br></div><div>I appreciated your help, mainly cause you gave a important hint into the computation of vertical velocity via kinematic method. It seems to be a nice way to follow. You're right! However, as this method is very simple, we should worry about errors implicated in. This is the cause I should compute the vertical velocity (or pressure velocity in units of mb/s) using the omega equation. Furthermore, I need to calculate it in a 3-D spatial domain instead of in one single level. </div><div><br></div><div>Thank you very much Jeff.</div><div><br></div><div> I'll keep waiting for other hints and help. </div><div><br></div><div>Cheers,</div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-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>-----------------------------------------------------------------------------</font></span></div><div><span style="font-family: arial, sans-serif; font-size: 13px; border-collapse: collapse; "><span style="border-collapse: separate; font-family: arial; font-size: small; "><font color="#333333">Av. Darcy Vargas, 1200, Manaus-AM Brasil<br>Work phone: (92) 3878 4333<br>Cell phone : (92) 8196 7122<br>Skype:<span style="background-color: rgb(255, 255, 255); "> veiga_j.a.p.</span><br></font></span></span></div><div><font color="#333333"><span style="font-family: arial, sans-serif; font-size: 13px; border-collapse: collapse; ">-----------------------------------------------------------------------------</span><br>CV: <a href="http://lattes.cnpq.br/4027612512091565" target="_blank"><font color="#333333" style="background-color: rgb(255, 255, 255); ">http://lattes.cnpq.br/4027612512091565</font></a><br>URL:<a href="http://scientificmet.wordpress.com/" target="_blank"><font style="background-color: rgb(255, 255, 0); ">http://scientificmet.wordpress.com/</font></a><br><span style="font-family: arial, sans-serif; font-size: 13px; border-collapse: collapse; ">-----------------------------------------------------------------------------</span></font></div></span></div></div></span></span>
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<br><div><div>On Aug 31, 2011, at 5:22 PM, Jeffrey Duda wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">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>
-----------------------------------------------------------------------------</font></span></div><div><span style="font-family:arial, sans-serif;font-size:13px;border-collapse:collapse"><span style="border-collapse:separate;font-family:arial;font-size:small"><font color="#333333">Av. Darcy Vargas, 1200, Manaus-AM Brasil<br>
Work phone: (92) 3878 4333<br>Cell phone : (92) 8196 7122<br>Skype:<span style="background-color:rgb(255, 255, 255)"> veiga_j.a.p.</span><br></font></span></span></div><div><font color="#333333"><span style="font-family:arial, sans-serif;font-size:13px;border-collapse:collapse">-----------------------------------------------------------------------------</span><br>
CV: <a href="http://lattes.cnpq.br/4027612512091565" target="_blank"><font style="background-color:rgb(255, 255, 255)" color="#333333">http://lattes.cnpq.br/4027612512091565</font></a><br>URL:<a href="http://scientificmet.wordpress.com/" target="_blank"><font style="background-color:rgb(255, 255, 0)">http://scientificmet.wordpress.com/</font></a><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>
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