<div dir="ltr"><div>re: "<font face="Helvetica Neue, Helvetica, Arial, sans-serif">My problem is why stations out of WRF domain, got interpolated values?!!"</font></div><div><font face="Helvetica Neue, Helvetica, Arial, sans-serif"><br></font></div><div>I looked at the C-interface and the fortran subroutine used by NCL.</div><div><br></div><div>I see the issue. I also remember the circumstances.</div><div><br></div><div>---<br></div><div><a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/rcm2points.shtml"><b>rcm2points</b></a> was introduced a decade+ years ago. Originally, it used an inverse distance approach for interpolation. Subsequently, bilinear interpolation was introduced. For bilinear interpolation, the target grid point was <b>required to have 4 surrounding grid points</b>.</div><div><br></div><div>Subsequently, some users wanted locations "just outside" the defined grid space to be interpolated. As I recall, several iterations of assorted users requested features/options were tested. The idea was to make multiple options available to the users. For some forgotten reason(s), these were not implemented with the C-interface. <br></div><div>In fact, the original subroutine had a section appended that would accommodate the desired features. Suffice it to say, a partial implementation was distributed. <br></div><div><br></div><div>===</div><div>Currently, users will have to only<b> input </b>values within the grid boundaries</div><div>or</div><div>remove the returned points outside the grid region.</div><div><br></div><div>D<br></div><div><br></div><div> <br></div><br><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Sep 11, 2019 at 10:39 AM Ehsan Taghizadeh via ncl-talk <<a href="mailto:ncl-talk@ucar.edu" target="_blank">ncl-talk@ucar.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div class="gmail-m_-6883868943309754054gmail-m_5053647183332955242ydp851e84c5yahoo-style-wrap" style="font-size:16px"><div style="font-family:bookman old style,new york,times,serif"></div>
<div dir="ltr" style="font-family:bookman old style,new york,times,serif"><span><span style="font-family:Helvetica Neue,Helvetica,Arial,sans-serif"> td2 = </span><a shape="rect" href="https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_getvar.shtml" style="color:rgb(25,106,212);text-decoration-line:underline;font-family:Helvetica Neue,Helvetica,Arial,sans-serif" rel="nofollow" target="_blank">wrf_user_getvar</a><span style="font-family:Helvetica Neue,Helvetica,Arial,sans-serif">(fw,"td2",-1) "***works***"</span></span></div><div dir="ltr"><font face="Helvetica Neue, Helvetica, Arial, sans-serif">and</font></div><div dir="ltr"><font face="Helvetica Neue, Helvetica, Arial, sans-serif"><span><span style="font-family:Helvetica Neue,Helvetica,Arial,sans-serif"> td2=fw->td2(0,:,:) "***didn't work***"</span></span></font></div><div dir="ltr"><font face="Helvetica Neue, Helvetica, Arial, sans-serif">likely, "td2" is diagnostic and is not in the file. It should be computed via "wrf_user_getvar".</font></div><div dir="ltr"><font face="Helvetica Neue, Helvetica, Arial, sans-serif">My problem is why stations out of WRF domain, got interpolated values?!!</font></div><div dir="ltr"><div style="font-family:bookman old style,new york,times,serif" dir="ltr"><br></div><div dir="ltr"><i><font face="times new roman, new york, times, serif">Sincerely</font></i></div><div dir="ltr"><i><font face="times new roman, new york, times, serif">Ehsan</font></i></div></div>
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On Wednesday, September 11, 2019, 07:24:50 PM GMT+4:30, Dennis Shea <<a href="mailto:shea@ucar.edu" target="_blank">shea@ucar.edu</a>> wrote:
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<div><div id="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190"><div><div dir="ltr"><div> ---<br clear="none"></div><div><div> td2 = <a rel="nofollow" shape="rect" href="https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_getvar.shtml" target="_blank"><b>wrf_user_getvar</b></a>(fw,"td2",-1) ; td2=fw->td2(0,:,:) ******didn't work****</div> printVarSummary(td2)<br clear="none"> printMinMax(td2,0)</div><div>---</div><div>Likely: <br clear="none"></div><div><br clear="none"></div><div> [1] td2' is not on the file <br clear="none"></div><div> [2] one of the variables needed to derive 'td2' is not present on the file.</div><div> [3] you have an old version of 'wrf_user_getvar'</div><div><br clear="none"></div><div><b>%> </b>less WRFUserARW.ncl <=== 6.5.0<br clear="none"></div><div><br clear="none"></div><div> if( variable .eq. "td2" ) then<br clear="none"> ;; function wrf_td needs qv and pressure (Pa) on input and returns dewpoint temperature on return<br clear="none"> PSFC = _get_wrf_var(file_handle,"PSFC",time)<br clear="none"> Q2 = _get_wrf_var(file_handle,"Q2",time)<br clear="none"> td = wrf_td( PSFC , Q2 )<br clear="none"> copy_VarAtts_except(Q2,td,(/"description","units"/))<br clear="none"> td@description = "2m Dewpoint Temperature" ; Overwrite return description<br clear="none"> return(td)<br clear="none"> end if</div><br clear="none"></div><br clear="none"><div class="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190gmail_quote"><div class="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190yqt4376619820" id="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190yqt60782"><div class="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190gmail_attr" dir="ltr">On Wed, Sep 11, 2019 at 6:22 AM Ehsan Taghizadeh via ncl-talk <<a rel="nofollow" shape="rect" href="mailto:ncl-talk@ucar.edu" target="_blank">ncl-talk@ucar.edu</a>> wrote:<br clear="none"></div><blockquote class="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div class="gmail-m_-6883868943309754054gmail-m_5053647183332955242yiv7195775190gmail-m_9065354707909077185yahoo-style-wrap" style="font-family:bookman old style,new york,times,serif;font-size:16px"><div dir="ltr">Dears,</div><div dir="ltr">I forgot to attach output file from interpolation.</div><div dir="ltr">At the attachment, stations like "40899" or "40890" got "<span>9969209968386869046778552952102584320.0</span>" value. These stations don't locate in wrf domain 2. However, stations like "40745" has values, in spite of locating out of domain 2.</div><div dir="ltr"><i><font size="2"><br clear="none"></font></i></div><div dir="ltr"><i><font size="2">Sincerely</font></i></div><div dir="ltr"><i><font size="2">Ehsan</font></i></div></div></div>_______________________________________________<br clear="none">
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