<html><head><style>body{font-family:Calibri,Arial;font-size:13px}</style></head><body style="word-wrap:break-word;line-break:after-white-space"><div id="bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><div id="bloop_customfont" style="margin:0px">Dear Ehsan,</div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">First, apologies to NCL users for the back and forth as this seems much more of an understanding into interpolation techniques than a typical NCL user problem.</div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">The statement "That is why more commonly higher resolution grids would be interpolated to lower resolution.” was not made in isolation. It has to be read in context.</div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">Let me explain further: If you want to quantitatively evaluate some datasets (as you are trying to do in your paper), one will ideally want to regrid the different grids to a common grid. </div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">In your case as you mention, 3 gridded datasets with 0.1, 0.5 and 0.75 resolution respectively. For a quantitative analysis of these datasets, one will be required to interpolate to the lowest resolution grid, i.e 0.75. However if this is not done, then one will have to explain why another approach was preferred (as mentioned in my earlier mail, certain analysis may be sensitive to interpolation and using the wrong technique may lead to misleading results). </div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">On the reviewer question, you will have to draw that conclusion from these discussions. I will however mention that you should discuss how higher resolution grids may have more information (detail) than one with lower resolution. For instance higher resolution dataset will capture certain spatial distribution of say precipitation which may not be necessarily captured in lower resolution data.</div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">I will entreat you to spend some time to read Dennis’s overview on regridding here: <a href="https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview">https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview</a></div><div id="bloop_customfont" style="margin:0px"></div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">Hope this helps.</div><div id="bloop_customfont" style="margin:0px"><br></div><div id="bloop_customfont" style="margin:0px">Cheers </div><div id="bloop_customfont" style="margin:0px">Kwesi</div></div> <br><p class="airmail_on">On 18 July 2020 at 13:11:49, Ehsan Taghizadeh via ncl-talk (<a href="mailto:ncl-talk@mailman.ucar.edu">ncl-talk@mailman.ucar.edu</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>
<title></title>
<div class="ydp1649ca5byahoo-style-wrap" style="font-family:bookman old style,new york,times,serif;font-size:16px">
<div style="font-size:16px"></div>
<div dir="ltr" style="font-size:16px">Dears
Ian and Kwesi,</div>
<div dir="ltr" style="font-size:16px">I
really appreciate for your helpful comments. I learnt much from
them. However, about Kwesi's comment, may I ask why someone wanna
interpolate higher resolution to the lower resolution, as you said
"<span><span style="color:rgb(0,0,0);font-family:Calibri,Arial">That is why
more commonly higher resolution grids would be interpolated to
lower resolution</span></span>".</div>
<div dir="ltr" style="font-size:16px">
<br></div>
<div dir="ltr" style="font-size:16px">
<br></div>
<div dir="ltr" style="font-size:16px">May I
ask more help?</div>
<div dir="ltr" style="font-size:16px">My work
included different grid data with different spatial resolution;
0.1, 0.5 and 0.75 degree. I think I should reply to the referee
related to these spatial resolution differences which included in
my work, maybe the influence of these differences in the
interpolation.</div>
<div dir="ltr" style="font-size:16px">The
referee asked: "<span style="font-family:Verdana,sans-serif;font-size:8.5pt">Please
discuss also the spatial scale resolution differences in products
and interpolation implications."</span></div>
<div dir="ltr" style="font-size:16px">
<br></div>
<div dir="ltr" style="font-size:16px">
<br></div>
<div dir="ltr" style=""><i style=""><font size="2">Sincerely,</font></i></div>
<div dir="ltr" style=""><i style=""><font size="2">Ehsan</font></i></div>
<div style="font-size:16px"><br></div>
</div>
<div id="yahoo_quoted_5201450317" class="yahoo_quoted">
<div style="font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:13px;color:#26282a">
<div>On Saturday, July 18, 2020, 12:00:41 PM GMT+4:30, Kwesi A.
Quagraine <<a href="mailto:starskykwesi@gmail.com">starskykwesi@gmail.com</a>> wrote:</div>
<div><br></div>
<div><br></div>
<div>
<div id="yiv8752248087">
<div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
Dear Ehsan,</div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
<br clear="none"></div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
Follow from Ian’s explanation; as an example, lower resolution
grids have less spatial variance than higher resolution grids and
interpolating the lower resolution to a higher resolution does not
change this. Thus taking a lower resolution grid to a higher
resolution grid does not add information. The interpolated data
will have low spatial and temporal variance.</div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
That is why more commonly higher resolution grids would be
interpolated to lower resolution. </div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
<br clear="none"></div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
This information has to be explicitly stated in your paper; because
there are some analysis that are sensitive to interpolation and
readers have to bear that in mind when comparing results.</div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
<br clear="none"></div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
Hope this helps.</div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
<br clear="none"></div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
Regards</div>
<div id="yiv8752248087bloop_customfont" style="font-family:Calibri,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px">
Kwesi</div>
<div class="yiv8752248087yqt4842173529" id="yiv8752248087yqtfd52397">
<p class="yiv8752248087airmail_on">On 17 July 2020 at 18:48:39, Ian
Harris (ENV - Staff) via ncl-talk (<a rel="nofollow" shape="rect" target="_blank" href="mailto:ncl-talk@mailman.ucar.edu">ncl-talk@mailman.ucar.edu</a>)
wrote:</p>
<blockquote class="yiv8752248087clean_bq" type="cite">
<div dir="ltr"></div>
</blockquote>
</div>
</div>
<div class="yiv8752248087yqt4842173529" id="yiv8752248087yqtfd40799"></div>
<div>
<div class="yiv8752248087yqt4842173529" id="yiv8752248087yqtfd75618">
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Hi,</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br clear="none"></div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I'd say they want you to examine the resolution of your input and
output data, in case the interpolation could be judged, er,
'optimistic'. For instance, if I had data on a 5° grid, I could
easily interpolate it onto a 0.5° grid, but there are implications
because you're not inventing new data, you're still stuck with the
5° data but on a finer grid.</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br clear="none"></div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Cheers</div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br clear="none"></div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Harry<br clear="none"></div>
<div id="yiv8752248087appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div dir="ltr" id="yiv8752248087divRplyFwdMsg"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> ncl-talk <<a rel="nofollow" shape="rect" target="_blank" href="mailto:ncl-talk-bounces@mailman.ucar.edu">ncl-talk-bounces@mailman.ucar.edu</a>>
on behalf of Ehsan Taghizadeh via ncl-talk <<a rel="nofollow" shape="rect" target="_blank" href="mailto:ncl-talk@mailman.ucar.edu">ncl-talk@mailman.ucar.edu</a>><br clear="none">
<b>Sent:</b> 17 July 2020 17:12<br clear="none">
<b>To:</b> Ncl-talk <<a rel="nofollow" shape="rect" target="_blank" href="mailto:ncl-talk@ucar.edu">ncl-talk@ucar.edu</a>><br clear="none">
<b>Subject:</b> [ncl-talk] linint2_point</font>
<div> </div>
</div>
<div>
<p style="border:4px;border-style:solid;border-color:#ff0000;padding:0.5em;text-align:center">
<b>Warning:</b> This email is from outside the UEA system. Do not
click on links or attachments unless you expect them from the
sender and know the content is safe.</p>
<div>
<div class="yiv8752248087x_yahoo-style-wrap" style="font-family:bookman old style,new york,times,serif;font-size:16px">
<div dir="ltr">Dear NCL group,<br clear="none"></div>
<div dir="ltr">I hope you're doing great.</div>
<div dir="ltr">I have a general question and I hope I could have
your help, as usual.</div>
<div dir="ltr">In one paper I wrote "<span><span lang="EN-GB" style="font-size:12.0pt;line-height:200%;font-family:New serif">The interpolation was done using the bilinear
method in NCL (NCAR Command Language)</span></span>". Actually, I
interpolated some grid precipitation products on gauged stations
using "linint2_points" from NCL.</div>
<div dir="ltr">The referee commented "<span><span style="font-size:8.5pt;line-height:107%;font-family:sans-serif;color:black">With
how many points? Please discuss also the spatial scale resolution
differences in products and interpolation
implications.</span></span>"</div>
<div dir="ltr">I wanna reply "<span><span style="font-size:11.0pt;line-height:107%;font-family:sans-serif">As
mentioned in the paper, we used NCL in the most programming. NCL
has a function named linint2_points which interpolates from a
rectilinear grid to an unstructured grid using bilinear
interpolation based on the four closest grid points to a particular
(x, y) coordinate pair.</span></span>" However, I don't know how
reply to the part of discussing about different spatial resolution.
May I ask some help about that, please?</div>
<div dir="ltr"><br clear="none"></div>
<div dir="ltr"><i><font size="2">Sincerely,</font></i></div>
<div dir="ltr"><i><font size="2">Ehsan Taghizadeh</font></i></div>
<div dir="ltr"><i><font size="2">PhD student of
Meteorology,</font></i></div>
<div dir="ltr"><i><font size="2">Institute of Geophysics,
University of Tehran, Iran</font></i></div>
</div>
</div>
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