<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Dear <span style="font-family:arial,sans-serif;font-size:13px">Abayomi,</span></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">You're right! Thank you for your nice recommendation.</span></div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif;font-size:13px">Actually, I closely rechecked the script and found that neither </span><span style="font-size:13px">vapor pressure, mixing ratio nor even </span><span style="font-family:arial,sans-serif;font-size:13px">dewpoint temperature is needed! This is because, </span><span style="font-family:arial,sans-serif;font-size:13px">equation</span><span style="font-family:arial,sans-serif;font-size:13px"> (2) computes dewpoint temperature:</span></div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif;font-size:13px">That is:</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<span style="font-size:13px">'td = tc-((14.55+0.114*tc)*(1-0.01*</span><span style="font-size:13px">rh)+pow((2.5+0.007*tc)*(1-0.01*rh)</span><span style="font-size:13px">,3)+(15.9+0.117*tc)*pow((1-0.01*</span><span style="font-size:13px">rh),14))'</span><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-size:13px"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">As you see, dewpoint temperature is computed using "temperature+relative humidity" </span><span style="font-size:13px">in the above equation</span><span style="font-size:13px">.</span></div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">**************************************************************</span></div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">Therefore, 4 variables are needed to display moisture convergence:</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<span style="font-size:13px">Those are:</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">1- relative humidity (%)</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<span style="font-size:13px">2- air temperature (K)</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">3- u-wind component (m/s)</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<span style="font-size:13px">4-v-wind component (m/s)</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-size:13px">***********************************</span></div><div class="gmail_default">
<font face="arial, helvetica, sans-serif">The attached map is just as an example of "moisture convergence" over Iran. I chose a heavy storm (rainfall) over the country to display moisture convergence for that event. As it can be seen from the map, it clearly shows the convergence</font><span style="font-family:arial,helvetica,sans-serif">-positive</span><span style="font-family:arial,helvetica,sans-serif"> areas (light green to dark green) and divergence</span><span style="font-family:arial,helvetica,sans-serif">-negative</span><span style="font-family:arial,helvetica,sans-serif"> areas (light pink to dark rose</span><span style="font-family:arial,helvetica,sans-serif">).</span></div>
<div class="gmail_default" style><font face="arial, helvetica, sans-serif">In order to verify the output, I overlaid wind streams on the map for the same time. It's in a good agreement with the convergence and divergence regions.</font></div>
<div class="gmail_default" style><font face="arial, helvetica, sans-serif"><br></font></div><div class="gmail_default" style><font face="arial, helvetica, sans-serif">****************************************************************</font></div>
<div class="gmail_default" style><font face="arial, helvetica, sans-serif">By the way, I also found that there is a BUG in the script! </font></div><div class="gmail_default" style><font face="arial, helvetica, sans-serif">That is:</font></div>
<div class="gmail_default" style><span style="font-family:arial,helvetica,sans-serif;font-size:13px">'mconv = (<font color="#ff0000">-</font>1)*hdivg(u*mixr,v*mixr)*1e4'</span><font face="arial, helvetica, sans-serif"><br>
</font></div><div class="gmail_default" style><span style="font-family:arial,helvetica,sans-serif;font-size:13px"><br></span></div><div class="gmail_default" style><span style="font-family:arial,helvetica,sans-serif;font-size:13px">The <font color="#ff0000">minus sign </font>(-) </span><font face="arial, helvetica, sans-serif">reverses the convergence (positive areas) with divergence (negative areas)! What I mean is that, the regions that should be positive and convergence are displayed in a negative form! and vice versa. Therefore, the (<font color="#ff0000">-</font>) should be removed from the equation.</font></div>
<div class="gmail_default" style><font face="arial, helvetica, sans-serif">**********************************</font></div><div class="gmail_default" style><b><font face="arial, helvetica, sans-serif">Now, I wond</font>er what the unit of the moisture convergence is? Who knows? </b><b>Please see the enclosed file and</b><b> let me know ...</b><br>
<br><br>Thank you!<br>Mohsen</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div></div><div class="gmail_extra"><br clear="all"><div><div dir="ltr"><span><span style="font-size:11.0pt;line-height:115%;font-family:"Calibri","sans-serif";color:#888888"></span></span><span><span dir="RTL" style="font-size:11.0pt;line-height:115%;font-family:"Arial","sans-serif";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: (+98) 9119772934<br>e-mail: <a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a><br></div></div></div>
<br><br><div class="gmail_quote">On Sun, May 26, 2013 at 9:40 AM, Abatan Abayomi <span dir="ltr"><<a href="mailto:yomiabatan69@gmail.com" target="_blank">yomiabatan69@gmail.com</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>Hey Mohsen,</div><div> </div><div>You don't need to look for these data again. Equation (3) above will compute vapor pressure for you once you have Dew point temperature, likewise you get mixing ratio from equation (5).</div>
<div> </div><div>Hope that help you?</div><div> </div><div>Abayomi</div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On Sun, May 26, 2013 at 3:07 AM, Mohsen Soltani <span dir="ltr"><<a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@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 class="gmail_default" style="font-family:arial,helvetica,sans-serif">
Hi,</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">
I'm trying to display "Moisture Convergence" using the following script, which written by Michael Maxwell: </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">
************************************************************************</div><div class="gmail_default"><div class="gmail_default"><font face="arial, helvetica, sans-serif">* rh = Relative Humidity in % </font></div>
<div class="gmail_default">
<font face="arial, helvetica, sans-serif">* t = Temp at *set level in degrees Kelvin</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">* tc = Temp in degrees C</font></div><div class="gmail_default">
<font face="arial, helvetica, sans-serif">* td = Dewpoint at *set level in degrees C</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">* e = Vapor pressure<span style="white-space:pre-wrap"> </span></font></div>
<div class="gmail_default"><font face="arial, helvetica, sans-serif">* mixr = Mixing ratio</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">* u = U-wind in m/s</font></div><div class="gmail_default">
<font face="arial, helvetica, sans-serif">* v = V-wind in m/s</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">* mconv = moisture convergence/divergence. </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">'tc = (t-273.16)'</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">'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))'</font></div>
<div class="gmail_default"><font face="arial, helvetica, sans-serif">'vapr = 6.112*exp((17.67*td)/(td+243.5))'</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">'e = vapr*1.001+(lev-100)/900*0.0034'</font></div>
<div class="gmail_default"><font face="arial, helvetica, sans-serif">'mixr = 0.62197*(e/(lev-e))*1000'</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">'mconv = (-1)*hdivg(u*mixr,v*mixr)*1e4'</font></div>
<div class="gmail_default"><font face="arial, helvetica, sans-serif">'d mconv'</font></div><div class="gmail_default"><font face="arial, helvetica, sans-serif">********************************************************</font></div>
<div class="gmail_default"><font face="arial, helvetica, sans-serif"><br></font></div></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I've got all the required data to display MC, except for "vapor pressure and mixing ratio". Do you possibly know where I can get those data? Would you share the link(s) with me, please?</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"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
Thank you,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Mohsen</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div><div dir="ltr"><span><span style="color:rgb(136,136,136);line-height:115%;font-family:Calibri,sans-serif;font-size:11pt"></span></span><span><span lang="AR-SA" style="color:rgb(136,136,136);line-height:115%;font-family:Arial,sans-serif;font-size:11pt" dir="RTL"><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: (+98) 9119772934<br>e-mail: <a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a><br></div></div></div>
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