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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;font-family:"Arial",sans-serif;
color:black">Dear Sir,<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;font-family:"Arial",sans-serif;
color:black"> I have a problem to interpolate potential vorticity to isentropic levels. All
the data is derived from NCEP-DOE Reanalysis 2.<span style="color: rgb(68, 68, 68); font-family: Helvetica, Verdana, sans-serif; font-size: 15.2152px;"> </span>The potential vorticity is obtained via the function "pot_vort_isobaric", and so as to the potential
temperature. And the interpolation is done by the function "int2p_n". However, plenty of undefined grids appear in the the potential vorticity field at an isentropic level, see 350K. And the undefined grids, which locate at the same position for all time, are
not coherent with the <span>topography. </span>I have no idea that how does those undefined grids appear and how to deal with it? Thank you for your attention to this matter.<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;font-family:"Arial",sans-serif;
color:black">The version of NCL I used is 6.4. And my system is Ubuntu 16.0 on windows 10. My
script is as following and the image is attached.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black">;==========================================================================<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> begin<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> f1 = addfile("/mnt/e/NCEP/NCEP-R2/Daily/pv/<a href="http://pv.2010.nc" target="_blank" id="LPlnk284853" class="OWAAutoLink" previewremoved="true">pv.2010.nc</a>","r")<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> f2 = addfile("/mnt/e/NCEP/NCEP-R2/Daily/pt/<a href="http://pt.2010.nc" target="_blank" id="LPlnk162122" class="OWAAutoLink" previewremoved="true">pt.2010.nc</a>","r")<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> <span style="font-family: Arial, sans-serif; font-size: 16px;"> </span></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p><span style="font-family: Arial, sans-serif; font-size: 16px;"> pv = f1->pv</span></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> time = f1->time<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> theta = f2->pt<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><br>
</span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> ; lvl = ispan(270,400,10)*1.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> lvl = (/ 300, 350, 400/) ; user specified inentropic levels<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> lvl@description = "isentropic level" ; add meta data<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> lvl@units = theta@units<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> lvl!0 = "lvl"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> lvl&lvl = lvl<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><br>
</p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> ; pv2 = int2p(theta(time|:,lat|:,lon|:,level|:), \<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> ; pv(time|:,lat|:,lon|:,level|:), lvl, 1)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2 = int2p_n(theta, pv, lvl, 1, 1)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2!0 = "time" ; name dimensions<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2!2 = "lat"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2!3 = "lon"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2!1 = "lvl"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2&time = time ; assign coordinates<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2&lvl = lvl ; isentropic levels<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2&lat = pv&lat<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2&lon = pv&lon<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2@long_name = pv@long_name ; attributes<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> pv2@units = pv@units<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> ;------output <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> fNameo = "/mnt/e/NCEP/NCEP-R2/Daily/pv_pt/<a href="http://pv.2010.nc" target="_blank" id="LPlnk490240" class="OWAAutoLink" previewremoved="true">pv.2010.nc</a>"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> system("/bin/rm -f " + fNameo)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> fout = addfile(fNameo,"c")<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> fout@title = " potential vorticity"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> fout@creation_date = systemfunc("date")<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> filedimdef(fout,"time",-1,True)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"> fout->pv = pv2<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black">end<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black">;==========================================================================<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black">Yours,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-size:10.5pt;
font-family:"Arial",sans-serif;color:black">Nanshui<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US" style="font-size:12.0pt;font-family:SimSun;mso-fareast-font-family:DengXian;
mso-fareast-theme-font:minor-fareast;mso-bidi-font-family:SimSun"><o:p> </o:p></span></p>
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