<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Dear Friends,</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 have produced "Temperature Advection" using <span style="font-size:medium;color:rgb(0,0,0);font-family:monospace">cdiff</span> function, which is available at "GrADS Documentation Index":</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
<a href="http://www.iges.org/grads/gadoc/gadocindex.html" style="font-family:arial">http://www.iges.org/grads/gadoc/gadocindex.html</a></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">The full command is like this:</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium">
<code>define dtx = cdiff(t,x)</code></dd><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium"><code>define dty = cdiff(t,y)</code></dd><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium">
<code>define dx = cdiff(lon,x)*3.1416/180</code></dd><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium"><code>define dy = cdiff(lat,y)*3.1416/180</code></dd><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium">
<code>display -1*( (u*dtx)/(cos(lat*3.1416/180)*dx) + v*dty/dy )/6.37e6</code></dd><dd style="color:rgb(0,0,0);font-family:'Times New Roman';font-size:medium"><code><br></code></dd></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">
where,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">the variable t is temperature, u and v are the U and V components of the wind, respectively.</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">In fact, <span style="font-family:arial">I am working on an advective cooling event (frost) over
Iran. The frost event was occurred as a result of an extra-ordinary extension
of the Polar Vortex toward the lower latitudes. </span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">The attached are the outputs that I made, which the first one indicates the start of the frost event, and the second one shows the end of the event over the country. I have to say that, they are in a very good agreement with the synoptic charts as well as outputs from HYSPLIT trajectory model.<span style="font-family:arial"><br>
</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><p class="">Briefly speaking, is it really a temperature advection map? If
so, do you know what the unit of the temp advection is? And how it should be explained? </p><p class=""><br></p><p class="" style>Thank you!</p></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="font-size:11pt;line-height:115%;font-family:Calibri,sans-serif;color:rgb(136,136,136)"></span></span><span><span dir="RTL" style="font-size:11pt;line-height:115%;font-family:Arial,sans-serif;color:rgb(136,136,136)" 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>
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