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<p class="MsoNormal">I have been trying to use the function “wrf_user_intrp3d” and assumed it would work like the NCL documentation suggests.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Function wrf_user_intrp3d (var3d, vert, plot_type, loc, angle, logical)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am calling it as follows:<o:p></o:p></p>
<p class="MsoNormal"> rh_plane = wrf_user_intrp3d(rh,z,"v",plane,0.,opts)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">where rh is my relative humidity variable from wrfout (at time “it)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">rh = wrf_user_getvar(a,"rh",it) ; relative humidity<o:p></o:p></p>
<p class="MsoNormal">and z is my model heights<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">z = wrf_user_getvar(a, "z",it) ; grid point height<o:p></o:p></p>
<p class="MsoNormal">plane is defined as follows:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-indent:.5in">; Find the ij location for the Test Site (remains constant)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">test_lat = 35.0<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">test_lon = -85.7<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">llres = True<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">llres@ReturnInt = True ; Return integer values<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">locij = wrf_user_ll_to_ij(a, test_lon, test_lat, llres)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">locij = locij - 1 ; array pointers in NCL space<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">TestX = locij(0)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">TestY = locij(1)<o:p></o:p></p>
<p class="MsoNormal">; print("TestX (" + test_lat + "): " + TestX)<o:p></o:p></p>
<p class="MsoNormal">; print("TestY (" + test_lon + "): " + TestY)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-indent:.5in">; Find the ij location for the end point (change for different arcs)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">end_lat = 34.0<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">end_lon = -85.5<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">llres = True<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">llres@ReturnInt = True ; Return integer values<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">locij = wrf_user_ll_to_ij(a, end_lon, end_lat, llres)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">locij = locij - 1 ; array pointers in NCL space<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">EndX = locij(0)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in">EndY = locij(1)<o:p></o:p></p>
<p class="MsoNormal" style="text-indent:.5in"><o:p> </o:p></p>
<p class="MsoNormal"> plane = new(4,float)<o:p></o:p></p>
<p class="MsoNormal"> plane = (/ TestX, TestY, EndX, EndY /) ; start x;y & end x;y point<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">and, finally<o:p></o:p></p>
<p class="MsoNormal"> opts=True<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I would expect to get back rh_plane values along the radial of the defined “plane” at the heights specified in z. In this case, I defined 50 heights for WRF, so I have a nZ of 50 for the z/interpolation variable. I was baffled when I
got back 100 rh_plane values in the vertical. Looking through the source code for wrf_user_intrp3d (finally), I found that the function is just interpolating to a uniform 100 levels between the min and max Z values.<o:p></o:p></p>
<p class="MsoNormal"> z_max = max(z)<o:p></o:p></p>
<p class="MsoNormal"> z_min = 0.<o:p></o:p></p>
<p class="MsoNormal"> dz = 0.01 * z_max<o:p></o:p></p>
<p class="MsoNormal"> nlevels = tointeger( zmax/dz )<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Why doesn’t the routine use the levels that the user has input into the function?<o:p></o:p></p>
<p class="MsoNormal">Is there an improved wrf_user_intrp3d function? (Can I fix it and recompile it easily?)<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">--<o:p></o:p></p>
<p class="MsoNormal">John Trostel<o:p></o:p></p>
<p class="MsoNormal">Director – Severe Storms Research Center<o:p></o:p></p>
<p class="MsoNormal">Georgia Tech Research Institute<o:p></o:p></p>
<p class="MsoNormal">Atlanta, GA 30332-0857<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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