<div dir="ltr">Thanks guys,<div><br></div><div>solved it !</div><div><br></div><div><b style="font-size:12.8px">(1/p)*dTheta/d(lnp) (approximate)</b><br></div><div>
<p class=""><span style="background-color:rgb(255,255,255)"><font color="#ff0000">(0)<span class=""> </span>min=-0.0184797 max=0.00307985</font></span></p><p class=""><br></p><p class=""><b style="font-size:12.8px">dTheta/dp (direct)</b><br></p>
<p class=""><font color="#0000ff">(0)<span class=""> </span>min=-0.0149857 max=0.00320144</font></p><p class=""><font color="#0000ff"><br></font></p><p class=""><font color="#000000">They are similar! thanks</font></p><p class=""><span style="color:rgb(0,0,0)">Xi Chang</span><br></p></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 17, 2016 at 8:06 PM, Dennis Shea <span dir="ltr"><<a href="mailto:shea@ucar.edu" target="_blank">shea@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div> y = ln(p)<br></div> dy/dp = 1/p<br><br></div>so .... maybe<br><br><b>p*dTheta/d(lnp),</b><br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Wed, Aug 17, 2016 at 8:32 AM, Xi Chang <span dir="ltr"><<a href="mailto:xi.chang01@gmail.com" target="_blank">xi.chang01@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div><div><div><div><div><div>Hallo,<br><br></div>I tried to calculate dTheta/dp using center finite difference with the folllowing methods:<br><br></div>1. direct calculation of <b>dTheta/dp</b> using center finite difference<br><br></div>2. using this approximation <b> (1/p)*dTheta/d(lnp), </b>also using center finite difference.<br><br></div>BUT surprisingly this gives me different results, for instance the method 1 give ma value 100 K/Pa but the method 2 gives me much smaller values 0.0xxx K/Pa.<br><br></div>Thanks for suggestion.<span><font color="#888888"><br><br></font></span></div><span><font color="#888888">Chang<br></font></span></div>
<br></div></div>______________________________<wbr>_________________<br>
ncl-talk mailing list<br>
<a href="mailto:ncl-talk@ucar.edu" target="_blank">ncl-talk@ucar.edu</a><br>
List instructions, subscriber options, unsubscribe:<br>
<a href="http://mailman.ucar.edu/mailman/listinfo/ncl-talk" rel="noreferrer" target="_blank">http://mailman.ucar.edu/mailma<wbr>n/listinfo/ncl-talk</a><br>
<br></blockquote></div><br></div>
</blockquote></div><br></div>