<div dir="ltr"><div><div><div>Dear Arlindo,<br></div><div><br>Thank you for your answer.<br></div><br></div>I thought there were more complicated
calculations involved in this procedure and that it would be necessary
to write an equation in GrADS, that's why I sent an email to the list.<br><br></div>Thank you,<br><br></div><div class="gmail_extra"><br clear="all"><div><div dir="ltr"><div><font color="#134f5c" face="verdana, sans-serif"><br>
</font></div><font color="#134f5c"><div style="font-family:verdana,sans-serif"><font color="#134f5c" face="verdana, sans-serif"><br></font></div><font face="times new roman, serif">Júlio B. Chiquetto,</font></font><div><span style="background-color:rgb(255,255,255)"><font color="#134f5c" face="times new roman, serif">Doutorando em Climatologia pelo Programa de Pós-Graduação em Geografia Física da Universidade de São Paulo.</font></span></div>
<div><span style="background-color:rgb(255,255,255)"><font color="#134f5c" face="times new roman, serif"><br></font></span></div><div><div><span style="background-color:rgb(255,255,255)"><font color="#134f5c" face="times new roman, serif">PhD Student in Climatology at the Post-Graduation Program in Physical Geography of the University of Sao Paulo.</font></span></div>
</div></div></div>
<br><br><div class="gmail_quote">On 21 May 2014 21:42, Arlindo da Silva <span dir="ltr"><<a href="mailto:dasilva@alum.mit.edu" target="_blank">dasilva@alum.mit.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 class="">On Wed, May 21, 2014 at 6:48 PM, Júlio Barboza Chiquetto <span dir="ltr"><<a href="mailto:julio22@gmail.com" target="_blank">julio22@gmail.com</a>></span> wrote:<br></div><div class="gmail_extra">
<div class="gmail_quote"><div class="">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><div>Hello dear users,<br></div>I have a tropospheric ozone time series in micrograms/m3, but I need to display it in ppm. I know it's a simple issue, but I don't have much experience in writing formulas in GrADS and I was wondering if other users might have already needed a script that does this unit conversion when displaying a variable.<br>
</div></div></blockquote><div><br></div></div><div>Consult the wikipedia to learn about the part-per notation:</div><div><br></div><div> <a href="http://en.wikipedia.org/wiki/Parts-per_notation" target="_blank">http://en.wikipedia.org/wiki/Parts-per_notation</a></div>
<div> </div><div>Notice that ppm (parts per million) implies mass mixing ratio (ppmv is used for volume mixing ratio). All you have to do is to divide your ozone density time series by the air density which in principle depends on pressure and temperature:</div>
<div><br></div><div> rho = p / (RT) </div><div><br></div><div>If you express the air density in micrograms/m3 as your ozone density you will have your mixing ratio in Kg/Kg. Mutiply it by 1,000,000 to have ppm. <span class="HOEnZb"><font color="#888888"><br>
</font></span></div><span class="HOEnZb"><font color="#888888"><div><br></div><div> Arlindo</div><div><br></div></font></span></div><span class="HOEnZb"><font color="#888888">-- <br><font color="#006600" size="6" face="'comic sans ms', sans-serif"><span style="font-family:Helvetica;font-size:12px"></span><span></span><span></span>Arlindo da Silva</font><br>
<font size="4"><i><a href="mailto:dasilva@alum.mit.edu" target="_blank">dasilva@alum.mit.edu</a></i></font>
</font></span></div></div>
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