<div dir="ltr"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Dear All,</div><div><br></div><div>I am trying to compute the meridional gradient of of potential temperature (925hPa). </div><div>Then create a latitude-time plot.</div><div>I am getting very small magnitudes of the gradient which is not consistent with the literature that I am following (<a href="http://wwwoa.ees.hokudai.ac.jp/people/yamazaki/D/Dthesis_yOkada.pdf">http://wwwoa.ees.hokudai.ac.jp/people/yamazaki/D/Dthesis_yOkada.pdf</a>).</div><div><br></div><div>Here's the script that I am using:</div><div><div>'sdfopen /mnt/dat/wind/vwind/10m/<a href="http://pentad_ensmean_vwnd_surf_1981-2010.nc">pentad_ensmean_vwnd_surf_1981-2010.nc</a>'</div><div><br></div><div>'set display color white'</div><div>'c'</div><div>'set gxout shaded'</div><div>'set mpdset hires'</div><div>'set grid off'</div><div>'set grads off'</div><div>'set parea 0.5 8 2 10.5'</div><div>'set font 1'</div><div>'set lat -90 90'</div><div>'set lon 0 360'</div><div>'set dfile 1'</div><div>'set t 1 73'</div><div>'define t=pottmp'</div><div>'set dfile 2'</div><div>'set t 1 73'</div><div>'define u=uwnd'</div><div>'set dfile 3'</div></div><div><div>'set t 1 73'</div><div>'define v=vwnd'</div><div><br></div><div><b>'define dty = cdiff(t,y)'</b></div><div><b>'define Re = 6.37e6'</b></div><div><b>'define dy = Re*cdiff(lat,y)*(3.1416/180)'</b></div><div><b>'define mergrad = -1*v*dty/dy'</b></div><div><br></div><div>'set t 1 73'</div><div>'set lat 15 45'</div><div>'set x 1'</div><div>'set xyrev on'</div><div>'set xaxis 1 73'</div><div>'define a = ave(mergrad,lon=110,lon=120)'</div><div>'d a'</div><div>'cbarn'</div><div>'printim test.png'</div><div>'quit'</div></div><div><br></div><div>Attached is the output image. In the literature,the unit is between -3 and 3, while in my case its x10-5.</div><div><br></div><div><br></div><div>Any suggestions on how I can do this correctly?</div><div><br></div><div><br></div><div>Lyndz</div><div><br></div></div></div></div></div></div></div></div></div>
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