<div dir="ltr">Hi Mohsen,<div><br></div><div style>Thank you for the help.</div><div style><br></div><div style>Could you please send me the script of you attached .jpg file so that it directs me to visualize my results?</div>
<div style><br></div><div style>Looking forwards to hearing from you.</div><div style><br></div><div style>Thank you Mohsen,</div><div style><br></div><div style>Regards,</div><div style><br></div><div style>KIshore</div>
<div style><br></div><div style><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jun 11, 2013 at 11:28 AM, Mohsen Soltani <span dir="ltr">&lt;<a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a>&gt;</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="gmail_default" style="font-family:arial,helvetica,sans-serif">Hi Kishore,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">


Use the following script to calculate moisture convergence:</div><div class="gmail_default"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">***********************************************************************</div>


<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">************************************************</div>
<div class="gmail_default"><div class="im"><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">* rh    = Relative Humidity in % </font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">



<font face="arial, helvetica, sans-serif">* t     = Temp at *set level in degrees Kelvin</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">* tc    = Temp in degrees C</font></div>


<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">
<font face="arial, helvetica, sans-serif">* td    = Dewpoint at *set level in degrees C</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">* e     = Vapor pressure<span style="white-space:pre-wrap">        </span></font></div>



<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">* mixr  = Mixing ratio</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">


<font face="arial, helvetica, sans-serif">* u     = U-wind in m/s</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">
<font face="arial, helvetica, sans-serif">* v     = V-wind in m/s</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">* mconv = moisture convergence/divergence. </font></div>


<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">
<font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">&#39;tc = (t-273.16)&#39;</font></div></div>
<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">

<font face="arial, helvetica, sans-serif">&#39;td = tc-((14.55+0.114*tc)*(1-0.01*rh) + pow((2.5+0.007*tc)*(1-0.01*rh),3) + (15.9+0.117*tc)*pow((1-0.01*rh),14))&#39;</font></div><div class="im">
<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">&#39;vapr = 6.112*exp((17.67*td)/(td+243.5))&#39;</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">


<font face="arial, helvetica, sans-serif">&#39;e = vapr*1.001+(lev-100)/900*0.0034&#39;</font></div>
<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">&#39;mixr = 0.62197*(e/(lev-e))*1000&#39;</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">


<font face="arial, helvetica, sans-serif">&#39;mconv = (1)*hdivg(u*mixr,v*mixr)*1e4&#39;</font></div>
<div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">&#39;d mconv&#39;</font></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px">


<font face="arial, helvetica, sans-serif">****************************</font></div></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><font face="arial, helvetica, sans-serif">**************************************************</font></div>


<div class="gmail_default"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif">I have to say that neither </span>vapor pressure, mixing ratio nor even <span style="font-family:arial,sans-serif">dewpoint temperature is needed! This is because, </span><span style="font-family:arial,sans-serif">equation</span><span style="font-family:arial,sans-serif"> (2) computes dewpoint temperature:</span></div>


<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif">That is:</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">


&#39;td = tc-((14.55+0.114*tc)*(1-0.01*rh)+pow((2.5+0.007*tc)*(1-0.01*rh),3)+(15.9+0.117*tc)*pow((1-0.01*rh),14))&#39;</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px"> <br></div>


<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">**************************</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">Therefore, you only need 4 variables to calculate moisture convergence:</div>


<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">Those are:</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">


1- relative humidity (%)</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">2- air temperature (K)</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">


3- u-wind component (m/s)</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">4-v-wind component (m/s)</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">


*************************************************</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px">All you have to do is to define variables based on the equations in the script. For example:</div>


<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:13px"><br></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">define u = uwnd</font><br></div><div class="gmail_default">


<span style="font-family:arial,helvetica,sans-serif">define v = vwnd</span><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">define t = air</font><br>


</div><div class="gmail_default"><font face="arial, helvetica, sans-serif">define rh = rhum</font><br></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">**********************************************************</font></div>


<div class="gmail_default"><font face="arial, helvetica, sans-serif">I&#39;m attaching a &quot;moisture convergence plot&quot; over Iran. Based on the plot, the convergence (positive) areas shown in green color and vice versa. To verify my output, I overlaid wind streams. They are quite in a good agreement with convergence and divergence regions.</font></div>


<div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">BTW, that&#39;s a surface level. And as Davide suggested, the unit of the MC will be: </font><span style="font-family:&#39;Times New Roman&#39;,serif;font-size:9pt;line-height:115%">(g/kg*s</span><sup style="font-family:&#39;Times New Roman&#39;,serif;line-height:115%">-1</sup><span style="font-family:&#39;Times New Roman&#39;,serif;font-size:9pt;line-height:115%">)</span></div>


<div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">Good luck,</font></div>


<div class="gmail_default"><font face="arial, helvetica, sans-serif">Mohsen</font></div></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:13px"><br></div></div></div></div><div class="gmail_extra">
<div class="im">

<br clear="all"><div><div dir="ltr"><span><span style="font-size:11.0pt;line-height:115%;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:#888888"></span></span><span><span dir="RTL" style="font-size:11.0pt;line-height:115%;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#888888" lang="AR-SA"><span></span></span></span>--<div>


some are weather-wise some are otherwise!</div><div>--<br>Best Wishes,                                        <br>(Mr.) Mohsen Soltani<br>Climatology Grad Student (M.Sc.),<br>Faculty of Geography, University of Tehran, Tehran, Iran<br>


Tel: <a href="tel:%28%2B98%29%209119772934" value="+989119772934" target="_blank">(+98) 9119772934</a><br>e-mail: <a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a><br></div></div></div>

<br><br></div><div><div class="h5"><div class="gmail_quote">On Mon, Jun 10, 2013 at 9:59 PM, Kishore Ragi <span dir="ltr">&lt;<a href="mailto:kishoreragi@gmail.com" target="_blank">kishoreragi@gmail.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

<div dir="ltr">Dear users,<div><br></div><div>I can understand how to calculate moisture convergence with specific humidity/mixing ratio but, I have relative humidity.</div><div><br></div><div>Could anybody please help me how to calculate moisture convergence with relative humidity?</div>



<div><br></div><div>Thank you in advance,</div><div><br></div><div>Sincerely,</div><div><br></div><div>Kishore</div></div><div><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, May 30, 2013 at 7:11 PM, Mohsen Soltani <span dir="ltr">&lt;<a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a>&gt;</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="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif;font-size:13px">Dear Davide,</span><br>



</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">

<span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif;font-size:13px">It sounds logical! Thank you very much for your kindness.</span></div>



<span><font color="#888888">

<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">





<span style="font-family:arial,sans-serif;font-size:13px">Mohsen</span></div></font></span></div><div class="gmail_extra"><div><br clear="all"><div><div dir="ltr"><span><span style="font-size:11.0pt;line-height:115%;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:#888888"></span></span><span><span dir="RTL" style="font-size:11.0pt;line-height:115%;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;;color:#888888" lang="AR-SA"><span></span></span></span>--<div>





some are weather-wise some are otherwise!</div><div>--<br>Best Wishes,                                        <br>(Mr.) Mohsen Soltani<br>Climatology Grad Student (M.Sc.),<br>Faculty of Geography, University of Tehran, Tehran, Iran<br>





Tel: <a href="tel:%28%2B98%29%209119772934" value="+989119772934" target="_blank">(+98) 9119772934</a><br>e-mail: <a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a><br></div></div></div>




<br><br></div><div><div><div class="gmail_quote">On Thu, May 30, 2013 at 2:54 AM, Davide Sacchetti <span dir="ltr">&lt;<a href="mailto:davide.sacchetti@arpal.gov.it" target="_blank">davide.sacchetti@arpal.gov.it</a>&gt;</span> wrote:<br>





<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">specific humidity is defined as ratio of water vapor mass (g) over air<br>
mass (kg) (units: g/kg)<br>
mixing ratio is almost the same: ratio of water vapor mass (g) over DRY<br>
air mass (kg) (units: g/kg)<br>
<br>
your divergence is like d(u*mixr)/dx, then has units of (m/s * g/kg)/m:<br>
units should be g/kg*s-1<br>
<br>
bye bye<br>
Davide<br>
<div><div><br>
On Thu, 2013-05-30 at 01:39 -0700, Mohsen Soltani wrote:<br>
&gt; Dear GrADS Users,<br>
&gt;<br>
&gt;<br>
&gt; I employed the following script to display the moisture convergence.<br>
&gt; But, I don&#39;t know what is the unit of the output! Please see the<br>
&gt; attached plot and let me know what&#39;s your opinion.<br>
&gt;<br>
&gt;<br>
&gt; ************************************************************************<br>
&gt; * rh    = Relative Humidity in %<br>
&gt; * t     = Temp at *set level in degrees Kelvin<br>
&gt; * tc    = Temp in degrees C<br>
&gt; * td    = Dewpoint at *set level in degrees C<br>
&gt; * e     = Vapor pressure<br>
&gt; * mixr  = Mixing ratio<br>
&gt; * u     = U-wind in m/s<br>
&gt; * v     = V-wind in m/s<br>
&gt; * mconv = moisture convergence/divergence.<br>
&gt;<br>
&gt;<br>
&gt; &#39;tc = (t-273.16)&#39;<br>
&gt; &#39;td = tc-((14.55+0.114*tc)*(1-0.01*rh) + pow((2.5<br>
&gt; +0.007*tc)*(1-0.01*rh),3) + (15.9+0.117*tc)*pow((1-0.01*rh),14))&#39;<br>
&gt; &#39;vapr = 6.112*exp((17.67*td)/(td+243.5))&#39;<br>
&gt; &#39;e = vapr*1.001+(lev-100)/900*0.0034&#39;<br>
&gt; &#39;mixr = 0.62197*(e/(lev-e))*1000&#39;<br>
&gt; &#39;mconv = (1)*hdivg(u*mixr,v*mixr)*1e4&#39;<br>
&gt; &#39;d mconv&#39;<br>
&gt; ********************************************************<br>
&gt;<br>
&gt;<br>
&gt;<br>
&gt;<br>
&gt; Thank you,<br>
&gt; Mohsen<br>
&gt;<br>
&gt;<br>
&gt; --<br>
&gt; some are weather-wise some are otherwise!<br>
&gt; --<br>
&gt; Best Wishes,<br>
&gt; (Mr.) Mohsen Soltani<br>
&gt; Climatology Grad Student (M.Sc.),<br>
&gt; Faculty of Geography, University of Tehran, Tehran, Iran<br>
&gt; Tel: <a href="tel:%28%2B98%29%209119772934" value="+989119772934" target="_blank">(+98) 9119772934</a><br>
&gt; e-mail: <a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a><br>
&gt;<br>
</div></div>&gt; _______________________________________________<br>
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<br>
--<br>
--&gt; Attenzione cambio indirizzo: <a href="mailto:davide.sacchetti@arpal.gov.it" target="_blank">davide.sacchetti@arpal.gov.it</a><br>
--<br>
Davide Sacchetti<br>
Centro Funzionale Meteo Idrologico di Protezione Civile della Regione Liguria<br>
ARPAL Unità Tecnica Complessa di livello Regionale<br>
V.le Brigare Partigiane 2 16121 Genova (I)<br>
tel: <a href="tel:%2B39%20010%206437535" value="+390106437535" target="_blank">+39 010 6437535</a>                    fax: <a href="tel:%2B39%20010%206437520" value="+390106437520" target="_blank">+39 010 6437520</a><br>




mail: <a href="mailto:davide.sacchetti@arpal.gov.it" target="_blank">davide.sacchetti@arpal.gov.it</a>     web: <a href="http://www.meteoliguria.it" target="_blank">www.meteoliguria.it</a><br>
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