<div dir="ltr">Dear gradsusr community,<div><br></div><div>I am attempting to create a zonal mean plot of a variable (Q), which has 26 levels. </div><div><br></div><div>The vertical coordinates are "hybrid sigma pressure." I have created a data descriptor file and entered the vertical coordinates in the following manner: ZDEF 26 levels L1 L2 ... L26.</div><div><br></div><div>I have reviewed the GrADS documentation, and it seems that several examples suggest that the vertical coordinates should be in pure pressure coordinates and that GrADS may not read these hybrid coordinates.</div><div><br></div><div>The relevant ncdump infomration is provided below. Just below the dimensions, you can see that the formula from which the sigma coordinates are calculated from actual pressure and surface pressure are provided.</div><div><br></div><div>Has anyone attempted to plot hybrid sigma pressure coordinates in GrADS before? If so, would someone be able to provide an explanation of how to convert the vertical coordinate into something GrADS will read?</div><div><br></div><div>Thanks so much!</div><div>Corey</div><div><br></div><div>ncdump -c <a href="http://q.corey30.001.cam.2020-01-2089-12.nc">q.corey30.001.cam.2020-01-2089-12.nc</a><br></div><div>
<p class=""><span class="">netcdf q.corey30.001.cam.2020-01-2089-12 {</span></p>
<p class=""><span class="">dimensions:</span></p>
<p class=""><span class=""><span class=""> </span>lev = 26 ;</span></p>
<p class=""><span class=""><span class=""> </span>time = UNLIMITED ; // (840 currently)</span></p>
<p class=""><span class=""><span class=""> </span>lat = 192 ;</span></p>
<p class=""><span class=""><span class=""> </span>lon = 288 ;</span></p>
<p class=""><span class=""><span class=""> </span>nbnd = 2 ;</span></p>
<p class=""><span class="">variables:</span></p>
<p class=""><span class=""><span class=""> </span>double lev(lev) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lev:long_name = "hybrid level at midpoints (1000*(A+B))" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lev:units = "level" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lev:positive = "down" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lev:standard_name = "atmosphere_hybrid_sigma_pressure_coordinate" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lev:formula_terms = "a: hyam b: hybm p0: P0 ps: PS" ;</span></p>
<p class=""><span class=""><span class=""> </span>double time(time) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>time:long_name = "time" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>time:units = "days since 2004-01-01 00:00:00" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>time:calendar = "noleap" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>time:bounds = "time_bnds" ;</span></p>
<p class=""><span class=""><span class=""> </span>double lat(lat) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lat:long_name = "latitude" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lat:units = "degrees_north" ;</span></p>
<p class=""><span class=""><span class=""> </span>double lon(lon) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lon:long_name = "longitude" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>lon:units = "degrees_east" ;</span></p>
<p class=""><span class=""><span class=""> </span>double time_bnds(time, nbnd) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>time_bnds:long_name = "time interval endpoints" ;</span></p>
<p class=""><span class=""><span class=""> </span>float Q(time, lev, lat, lon) ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>Q:mdims = 1 ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>Q:units = "kg/kg" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>Q:long_name = "Specific humidity" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>Q:cell_methods = "time: mean" ;</span></p>
<p class=""><span class=""></span><br></p>
<p class=""><span class="">// global attributes:</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:Conventions = "CF-1.0" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:source = "CAM" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:case = "corey30" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:title = "UNSET" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:logname = "cgabriel" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:host = "ys0861" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:Version = "$Name$" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:revision_Id = "$Id$" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:initial_file = "/glade/p/acd/tilmes/inputdata/init/ccmi/b.e11.TSREFC2.f19.f19.ccmi23.1deg_26L.001" ;</span></p>
<p class=""><span class=""><span class=""> </span><span class=""> </span>:topography_file = "/glade/p/cesmdata/cseg/inputdata/atm/cam/topo/<a href="http://USGS-gtopo30_0.9x1.25_remap_c051027.nc">USGS-gtopo30_0.9x1.25_remap_c051027.nc</a>"</span></p></div></div>