[gradsusr] gradsusr Digest, Vol 75, Issue 29

Sun May 29 12:25:00 EDT 2016

Hi Jeff.

Thanks.  Fortunately I was able to use a couple of other tools to perform
the calculations

I did try plotting the data with an arbitrary set of vertical levels.  That
leads to an error message stating that ZDEF is now an invalid description
file record.  Even though I was able to handle this elsewhere, I would
still like to understand what I am doing wrong with GrADS.  I have copied
the dimension records from my data descriptor file below.  To the ZDEF
entries reflect what you mean by plotting the data with an arbitrary
set of vertical
levels?

XDEF lon 288 linear 0 1.25
YDEF lat 192 linear -90 0.94240837
ZDEF 26 levels 1000 970 930 850 800 700 600 500 420 370 300 270 230 200 160
140 120 100 85 70 50 40 25 15 8 4 (arbitrary z axis values)
*ZDEF 26 levels 992.556 970.554 929.648 867.160 787.702 696.796 600.524
510.455 433.895 368.817 313.501 266.481 226.513 192.539 163.662 139.115
118.250 100.514 85.439 70.059 53.114 37.230 23.944625 13.967214 7.388 3.544
(*values matching the sigma-pressure levels)*
TDEF time 840 linear 01jan2020 1mo

Thanks again!
Corey

On Sun, May 29, 2016 at 12:00 PM, <gradsusr-request at gradsusr.org> wrote:

> Send gradsusr mailing list submissions to
>         gradsusr at gradsusr.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://gradsusr.org/mailman/listinfo/gradsusr
> or, via email, send a message with subject or body 'help' to
>         gradsusr-request at gradsusr.org
>
> You can reach the person managing the list at
>         gradsusr-owner at gradsusr.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of gradsusr digest..."
>
>
> Today's Topics:
>
>    1. Re: Atmosphere_hybrid_sigma_pressure_coordinate (Jeff Duda)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 29 May 2016 00:16:50 -0500
> From: Jeff Duda <jeffduda319 at gmail.com>
> Subject: Re: [gradsusr] Atmosphere_hybrid_sigma_pressure_coordinate
> To: GrADS Users Forum <gradsusr at gradsusr.org>
> Message-ID:
>         <
> CAAig09BEnghZGYfm3kKgX-JWs9xyPSHBoFk+9P+FcsXs92he4A at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Have you actually tried just plotting the data with an arbitrary set of
> vertical levels? The values you specify for ZDEF in your control file do
> not have to exactly match the vertical levels of your data. What really
> matters is how many vertical levels there are.
>
> Now, if you want to start performing calculations such as the spatial
> average of Q at a specific level like 850 mb, that's a bit more tricky, but
> as long as you know the structure of the vertical levels, you should be
> able to calculate it.
>
> Jeff Duda
>
> On Thu, May 26, 2016 at 12:12 PM, Corey Gabriel <cjgabriel7 at gmail.com>
> wrote:
>
> > Dear gradsusr community,
> >
> > I am attempting to create a zonal mean plot of a variable (Q), which has
> > 26 levels.
> >
> > 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.
> >
> > 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.
> >
> > 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.
> >
> > 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?
> >
> > Thanks so much!
> > Corey
> >
> > ncdump -c q.corey30.001.cam.2020-01-2089-12.nc
> >
> > netcdf q.corey30.001.cam.2020-01-2089-12 {
> >
> > dimensions:
> >
> > lev = 26 ;
> >
> > time = UNLIMITED ; // (840 currently)
> >
> > lat = 192 ;
> >
> > lon = 288 ;
> >
> > nbnd = 2 ;
> >
> > variables:
> >
> > double lev(lev) ;
> >
> > lev:long_name = "hybrid level at midpoints (1000*(A+B))" ;
> >
> > lev:units = "level" ;
> >
> > lev:positive = "down" ;
> >
> > lev:standard_name = "atmosphere_hybrid_sigma_pressure_coordinate" ;
> >
> > lev:formula_terms = "a: hyam b: hybm p0: P0 ps: PS" ;
> >
> > double time(time) ;
> >
> > time:long_name = "time" ;
> >
> > time:units = "days since 2004-01-01 00:00:00" ;
> >
> > time:calendar = "noleap" ;
> >
> > time:bounds = "time_bnds" ;
> >
> > double lat(lat) ;
> >
> > lat:long_name = "latitude" ;
> >
> > lat:units = "degrees_north" ;
> >
> > double lon(lon) ;
> >
> > lon:long_name = "longitude" ;
> >
> > lon:units = "degrees_east" ;
> >
> > double time_bnds(time, nbnd) ;
> >
> > time_bnds:long_name = "time interval endpoints" ;
> >
> > float Q(time, lev, lat, lon) ;
> >
> > Q:mdims = 1 ;
> >
> > Q:units = "kg/kg" ;
> >
> > Q:long_name = "Specific humidity" ;
> >
> > Q:cell_methods = "time: mean" ;
> >
> >
> > // global attributes:
> >
> > :Conventions = "CF-1.0" ;
> >
> > :source = "CAM" ;
> >
> > :case = "corey30" ;
> >
> > :title = "UNSET" ;
> >
> > :logname = "cgabriel" ;
> >
> > :host = "ys0861" ;
> >
> > :Version = "$Name$" ;
> >
> > :revision_Id = "$Id$" ;
> >
> > :initial_file =
> >
> "/glade/p/acd/tilmes/inputdata/init/ccmi/b.e11.TSREFC2.f19.f19.ccmi23.1deg_26L.001"
> > ;
> >
> > :topography_file = "/glade/p/cesmdata/cseg/inputdata/atm/cam/topo/
> > USGS-gtopo30_0.9x1.25_remap_c051027.nc"
> >
> > _______________________________________________
> > gradsusr mailing list
> > gradsusr at gradsusr.org
> > http://gradsusr.org/mailman/listinfo/gradsusr
> >
> >
>
>
> --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> http://gradsusr.org/pipermail/gradsusr/attachments/20160529/1d67c2cb/attachment-0001.html
>
> ------------------------------
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>
> End of gradsusr Digest, Vol 75, Issue 29
> ****************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20160529/df1789ca/attachment.html 