<html><head></head><body><div class="ydp8fbf20dyahoo-style-wrap" style="font-family:bookman old style, new york, times, serif;font-size:16px;"><div><div><div dir="ltr" data-setdir="false">Dear NCL group,</div><div dir="ltr" data-setdir="false">I'm not sure if this question belongs to the WRF forum or the NCL forum, but I would appreciate any help on this. I want to plot a variable (TOT_DUST in my case) on the surface level from a WRF-Chem output. I used an NCL script and found that the wrf_user_interp_level function in this language can interpolate a horizontal slice from a three-dimensional WRF-ARW field at the given vertical level(s). I'm not sure how to use this function (or maybe another function) to plot a 4D variable on the surface level.</div><div>I look forward to hearing from you.</div></div><br></div><div><br></div><div class="ydp8fbf20dsignature"><div dir="ltr" style="font-family:old times, serif;font-size:16px;"><div><div dir="ltr" style="color:rgb(0, 0, 0);font-family:old times, serif;font-size:16px;"><i><font size="2">-----------------------------------------------------------------------------</font></i></div><div dir="ltr" style="color:rgb(0, 0, 0);font-family:old times, serif;font-size:16px;"><i><font size="2">Sincerely,</font></i></div><div dir="ltr" style="color:rgb(0, 0, 0);font-family:old times, serif;font-size:16px;"><i><font size="2">Ehsan Taghizade<br></font></i></div></div><br></div></div></div></body></html>