On Sun, Jun 26, 2011 at 2:43 AM, Shing <span dir="ltr"><<a href="mailto:midicarcas@gmail.com">midicarcas@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
hi <div><br></div><div>i want to take vertical derivative of humidity in the isobaric coordinates. i used the function cdiff:</div><div><br></div><div><br></div><div>define dq=cdiff(q,z)</div><div><br></div><div>but got error message saying </div>
<div>error from cdiff: specific dimension non varying</div><div>operation error: error from cdiff function</div><div>error occurred at column 1</div><div>define error: invalid expression</div><div><br></div><div>it works fine when i take horizontal derivatives, such as dq=cdiff(q,x) and dq=cdiff(q,y)</div>
<div><br></div><div>is it not the way to do vertical derivative in grads?</div><div><br></div><div>thank you very much!</div><div><br></div></blockquote><div><br></div><div>The opengrads extensions, libbjt (<span class="block"><font class="Apple-style-span" face="arial, helvetica, sans-serif">Ben-Jei Tsuang's library), contains a number of both horizontal and vertical advection functions:</font></span></div>
<div><br></div><div><a href="http://opengrads.org/doc/udxt/libbjt/libbjt.html#advection_functions">ADVECTION FUNCTIONS</a></div><div><br></div><div>By setting the wind to "1" you you be able to get the desired gradient.</div>
<div><br></div><div> Good Luck,</div><div><br></div><div> Arlindo</div><div><br></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div></div><font color="#888888"><div>shing</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Arlindo da Silva<br><a href="mailto:dasilva@alum.mit.edu">dasilva@alum.mit.edu</a><br>