<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi,<div class="">given height levels you can derive pressure without temperature using an <u class="">approximation</u>. Function <a href="http://ncl.ucar.edu/Document/Functions/Crop/prsatm_z_fao56.shtml" class="">http://ncl.ucar.edu/Document/Functions/Crop/prsatm_z_fao56.shtml</a> (requires NCL 6.4.0).</div><div class=""><br class=""></div><div class="">Having pressure and theta you can easily derive temperature using the definition Theta=T*(Psfc/P)^(Rd/cp). </div><div class=""><br class=""></div><div class="">It won’t be perfect given that you are not using temperature to derive pressure but shouldn’t be far off if you are below 30km and in normal conditions. </div><div class=""><br class=""></div><div class="">Cheers </div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">Il giorno 20 apr 2017, alle ore 22:45, steve kirby <<a href="mailto:thinjogger@gmail.com" class="">thinjogger@gmail.com</a>> ha scritto:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><font face="Times New Roman" size="3" class="">
</font><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class="">Hi,</font></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""><br class=""></font></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class="">My goal is to
use:</font></div><font face="Times New Roman" size="3" class="">
</font><p style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""> </font></p><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">skewT_PlotData()</font></div><font face="Times New Roman" size="3" class="">
</font><p style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""> </font></p><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">but I only have a surface pressure and potential
temperature, and then</font></div><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">potential temperature and wind dir and wind spd at many height levels.</font></div><font face="Times New Roman" size="3" class="">
</font><p style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""> </font></p><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" class=""><font size="3" class=""><font class=""><span class=""> </span>I am wondering if
there is any way via NCL to derive temperature and/or</font></font></font></div><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">pressure with height given this information.<span class=""> I</span>t seems</font></div><font face="Times New Roman" size="3" class="">
</font><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class="">with either the hypsometric or Poisson's equation I am
lacking at least one </font><font face="Calibri" size="3" class="">parameter.<span class=""> </span></font></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""><span class=""></span></font><br class=""></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""><span class=""><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class="">Hypsometric: P = Psfc * e**(-z/H) </div><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><span class=""> </span>Have z and Psfc,
and if one uses the approximation for scale height, H =</div><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class="">29.3 *<span class=""> </span>Tvirtual,
then Tvirtual = (1 + 0.61w) * T; I have w, however I</div><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class="">don't have T.</div><font face="Times New Roman" class="">
</font><p style="margin:0in 0in 0pt" class=""> </p><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class="">Poisson's: Theta = T * (Psfc/P)**0.286</div><font face="Times New Roman" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><span class=""> </span>Have Theta (potential T) and
Psfc, but no T or P. </div><font face="Times New Roman" class="">
</font></span></font></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""><span class=""><span class=""><br class=""></span></span></font></div><div style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""><span class=""></span>But
perhaps there is a way?<span class=""> </span></font></div><font face="Times New Roman" size="3" class="">
</font><p style="margin:0in 0in 0pt" class=""><font face="Calibri" size="3" class=""> </font></p><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">TIA,</font></div><font face="Times New Roman" size="3" class="">
</font><div style="margin: 0in 0in 0pt;" class=""><font face="Calibri" size="3" class="">Steve</font></div><font face="Times New Roman" size="3" class="">
</font></div>
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